Is fever a disease or not?

Is fever a disease or not?

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I have seen this question where the author is asking why people take drugs for fever. So my question is: Is fever is a disease or not?

I know pretty much nothing in medicine!

Fever is an abnormally high body temperature. Fever is a symptom and not a disease per se. Different medical conditions (incl. various infectious diseases) causes a patient to have fever.

Note that fever might be in some/most situations an adaptive response to a disease. In other words, for infectious disease causing fever, fever might be good for the host and not for the parasite. However this issue remains controversial (see the post linked in the OP's question for more info).

As GoodGravy said in the comments, many people get confused and consider fever as a disease instead of what it really is; a symptom. One likely reason for this confusion is that when one has fever, (s)he very often treat fever directly (taking drugs like Aspirin for example) rather than treating the underlying cause (the virus for example) of the fever.

Any malfunctioning in the body is the result of either external pathogens, environmental changes or it can be manifested by the body itself. Based on which we can call it a disease or a disorder.

Some can be viewed with the help of its underlying symptoms. Fever is a natural response of the human body to any kind of imbalance, for example, temperature fluctuations, infections, etc., and that is why we can get fever by any number of reasons. What is important is that it shows us of some other underlying reason of change. Therefore I think it's more of a symptom than a disease.

1.4: Theories in Science

  • Contributed by Suzanne Wakim & Mandeep Grewal
  • Professors (Cell Molecular Biology & Plant Science) at Butte College

An individual in this sketch is holding his nose to avoid breathing in the miasma. Miasma refers to a toxic vapor that people believed for centuries was a cause of many diseases, including cholera and plague. The idea that miasma causes diseases was first proposed in the second century B.C.E. by a prominent Greek physician named Galen. They believed that miasma, which is identifiable by its foul smell, emanates from rotting organic matter and sickens people who live close enough to inhale it. Miasma was the predominant explanation for disease transmission from the time of Galen until the germ theory of disease became widely accepted in the late 1800s.

Figure (PageIndex<1>): A man holding his nose to avoid breathing in a miasma

How is a fever diagnosed?

  • Digital thermometer (oral, rectal, or under the armpit)
  • Tympanic (ear) thermometer (not recommended in babies younger than 6 months of age)
  • Temporal artery (temperature taken across the forehead area)

Taking a temperature rectally is the most accurate method in children under 3 years of age. In older children and adults, take the temperature under the armpit or in the mouth. Talk with your healthcare provider about the best way to take your temperature.

Most thermometers today are digital, but there are some glass thermometers containing mercury still in use. Mercury is toxic substance and is dangerous to humans and the environment. Because glass thermometers can break, they should be disposed of properly in accordance with local, state, and federal laws. For information on how to safely dispose of a mercury thermometer, contact your local health department, waste disposal authority, or fire department.

Why fever can be your friend in times of illness

Fevers are more than just a symptom of illness or infection, claim researchers elevated body temperature sets in motion a series of mechanisms that regulate our immune system, they found.

Share on Pinterest Does elevated body temperature actually help to boost our immune response?

When we are healthy, our body temperature tends to gravitate around a constant 37°C (98.6°F).

But when our bodies are faced with an infection or virus, body temperature often goes up and we experience fever.

A slight fever is characterized by a minor rise in body temperature to about 38°C (100.4°F), with larger increases to around 39.5°C (103.1°F) counting as “high fever.”

When we have the flu, for instance, we may come down with a mild and somewhat uncomfortable fever, driving many of us to seek natural or over-the-counter remedies against it.

Fevers aren’t always a bad sign you may even have heard that mild fevers are a good indication that your immune system is doing its job. But fevers aren’t just a byproduct of our immune response.

In fact, it’s the other way around: an elevated body temperature triggers cellular mechanisms that ensure the immune system takes appropriate action against the offending virus or bacteria.

So say researchers hailing from two academic institutions in the United Kingdom: the University of Warwick in Coventry and the University of Manchester.

Senior researchers Profs. David Rand and Mike White led teams of mathematicians and biologists to understand what happens at cellular level when fever takes hold.

Their findings, which have recently been published in PNAS, reveal that higher body temperatures drive the activity of certain proteins that, in turn, switch genes responsible for the body’s immune response on and off, as required.

A signaling pathway called Nuclear Factor kappa B (NF-κB) plays an important role in the body’s inflammation response in the context of infection or disease.

NF-κB are proteins that help to regulate gene expression and the production of certain immune cells.

These proteins respond to the presence of viral or bacterial molecules in the system, and that is when they start switching relevant genes related to the immune response on and off at cellular level.

Dysregulated NF-κB activity has been linked with the presence of autoimmune diseases such as psoriasis, Crohn’s disease, and arthritis.

The researchers note that NF-κB activity tends to slow down the lower the body temperature. But when the body temperature is elevated over the usual 37°C (98.6°F), it tends to become more intense.

Why does this happen? The answer, they hypothesized, might be found by looking at a protein known as A20, encoded by the gene with the same name.

A20 is sometimes hailed as the “ gatekeeper ” of inflammatory responses, and the protein has a complex relationship with the NF-κB signaling pathway.

NF-κB switches on the gene that produces A20 protein, but the protein, in turn, regulates NF-κB activity, so that it is appropriately slow or intensive.

The researchers involved in the new study wondered whether blocking the expression of the A20 gene would affect the way in which NF-κB functioned.

And, sure enough, they found that in the absence of the A20 protein, NF-κB activity no longer reacted to changes in body temperature, and its activity therefore no longer increased in case of a fever.

These findings might also be relevant to the normal fluctuations in temperature that our bodies undergo every day, and how these may affect our response to pathogens.

As Prof. Rand explains, our body clock regulates our internal temperature and determines mild fluctuations — of about 1.5°C (34.7°F) at a time — during wakefulness and sleep.

So, he says, “[T]he lower body temperature during sleep might provide a fascinating explanation into how shift work, jet lag, or sleep disorders cause increased inflammatory disease.”

Although many genes whose expression is regulated by NF-κB were not temperature-sensitive, the researchers found that certain genes — which played a key role in the regulation of inflammation and which impacted cell communication — did, in fact, respond differently to different temperatures.

Together, the findings suggest that developing drugs to target temperature-sensitive mechanisms at cellular level could help us to alter the body’s inflammatory response when needed.

“ We have known for some time that influenza and cold epidemics tend to be worse in the winter when temperatures are cooler. Also, mice living at higher temperatures suffer less from inflammation and cancer. These changes may now be explained by altered immune responses at different temperatures.”

Prof. Mike White

Non-Specific Defense Mechanism in Human Body (With Diagram) | Biology

Non-specific defenses are the body’s first line of defense against diseases. They are not directed against a particular pathogen. Non-specific defenses guard against all infections, regardless of their cause. It is also called as innate immunity (Fig. 2).

Plants and many lower animals rely only on innate immunity and do not possess the second category of specific defense mechanisms. Non­specific defense mechanisms work against a wide variety of invaders. Innate immunity consists of various types of barriers that prevent entry of pathogens into the body.

Barriers in Human Body:

Anatomic barriers or physical barriers are barriers that prevent the entry of pathogens into the body.

a. The body’s most important anatomic barrier is the skin. The skin is a passive barrier to infectious agents such as bacteria and viruses. The organisms living on the skin surface are unable to penetrate the layers of dead skin at the surface.

Skin glands like the oil and sweat glands secrete acids that retard the growth of bacteria at the surface of the skin. The acidic environment can kill bacteria and other microorganisms. Sweat, saliva and tears also contain lysozyme that can attack the cell wall of bacteria.

b. Pathogens can also enter the body through the mouth and nose. However, non-specific defenses protect these openings. Mucous membranes lining the respiratory, digestive, urinary, and reproductive tracts secrete mucus that forms an effective barrier. Mucous, which is a sticky fluid traps pathogens. The mucous, cilia and hairs in the nose and throat trap viruses and bacteria.

ii. Physiological Barriers:

A number of physiological barriers protect the body against pathogens.

a. Acid secretion, i.e. HCI in the stomach destroys organisms that may enter the digestive system.

b. Lysozyme, an enzyme found in tears, saliva, sweat and tissue fluid attacks bacteria by dissolving the cell walls of many bacteria.

c. Ear wax or cerumen traps dust particles and kills bacteria and insects.

d. Complement complex is a group of 20 proteins which destroys bacteria in various ways.

e. Basic polypeptides in the blood can inactivate certain specific types of gram +ve bacteria.

f. Certain cells when infected with a virus release interferons, a class of glycoproteins. The interferons protect the surrounding uninfected cells. This is also referred to as cytokine barrier.

g. Fever occurs in the body as a response to an infection. It is not a disease and serves to inhibit the growth of disease causing microorganisms since microorganisms can only survive within a narrow range of temperature. Therefore fever often slows down or stops growth of microorganisms.

Antipyretic drugs such as paracetamol help in lowering the set point of the thermostat and provide relief from symptoms of fever. It is advisable to take the drug only in case of extremely high temperature to avoid irreversible damage to the brain.

iii. Phagocytic or Cellular Barriers:

Phagocytosis means ‘cellular ingestion of the invading agent’. Phagocytic cells include macrophages and neutrophil granulocytes that are capable of attacking and engulfing bacteria, viruses and other invading agents that enter the blood and tissues. These cells are formed in the bone marrow and are released into the blood as need arises. These cells can move through the pores of the blood vessels by diapedesis. The macrophages together with the neutrophils form the body’s reticulo­ endothelial system.

Neutrophils are mature cells that can attack and destroy bacteria in circulating blood while the macrophages are formed from monocytes. The macrophages are capable of destroying intra-tissue disease agents. Macrophages are found distributed throughout the body.

Inflammatory Response:

Despite the various barriers of the human body, pathogens sometimes enter the body and cause tissue injury. Chemicals, heat, trauma etc. may also cause tissue injury. The injured cells release chemicals like histamine, serotonin, prostaglandin, reaction products of complement system, bradykinin and lymphokines (released by a type of special cell T-cells). These chemicals starts a series of changes called the inflammatory response. The inflammatory response is a non-specific defense reaction of the body to tissue damage.

Inflammation is characterised by the following changes:

a. The local blood vessels dilate considerably and cause increase in capillary blood flow into the affected area and raises the temperature locally. The heat makes the environment unfavourable for microbes, promotes healing, raises mobility of white blood cells, and increases the metabolic rate of nearby cells.

b. The permeability of the capillary wall increases. This increases the leakage of fluid into the interstitial spaces.

c. The increased leakage causes the infected/ injured area to swell. This is called Oedema.

d. Clotting factors trigger formation of many small blood clots due to excessive amount of fibrinogen and other proteins. Interferons are also released by the macrophages and other white blood cells when viral infection occurs. The interferons make the uninfected cells resistant to infection.

e. Large number of granulocytes and monocytes migrate into the tissues. These cells clean up dead microbes, cells and debris. After the onset of severe inflammation, the number of neutrophils increases from a normal 4000-5000 to about 15000-25000 per microlitre. This increase in neutrophils is called neutrophilia.

f. The macrophages and the neutrophils destroys the pathogens by phagocytosis. The inflammatory response is often strong enough to stop the spread of disease-causing agents such as viruses, bacteria and fungi to the adjoining areas. The response begins with the release of chemical signals and ends with cleanup by monocytes. If this is not enough to stop the invaders, the complement system and the specific defense mechanisms act.

After several days of inflammation in the injured tissues, varying portions of dead neutrophils and macrophages, necrotic tissue and tissue fluid accumulate. This is called pus.

Complement System:

The complement system includes a group of about 20 protective proteins that are produced in the liver. Many of them are enzyme precursors. They are found in the plasma as well as the tissue spaces. They are designated C1 through C9, B and D protein. These are normally inactive and can be activated when the need arises.

Complement proteins become active in a sequence. This is referred to as cascade mechanism, i.e. C1 activates C2, etc. The final five proteins form a membrane attack complex (MAC) that embeds itself into the plasma membrane of the attacker.

Salts enter the invader, facilitating water to cross the membrane, swelling and bursting the microbe. Complement proteins also work along with the immune response by tagging to the outer surface of invaders for attack by phagocytes and complements the actions of the immune system.

Interferons and Natural Killer Cells – Defense Against Viruses:

Two components of the immune system fight only viruses, interferons and natural killer cells. Since these components attack many types of viruses, they are considered as non-specific defenses.

a. Interferon is a protein that interferes with the replication of viruses. Interferons are species-specific chemicals produced by cells that are attacked by virus. It alerts the neighbouring uninfected cells to resist attack by the virus (Fig. 3). It slows down the progress of infection and often gives the specific defenses of the immune system time to respond. Interferon and natural killer cells also help to fight against cancer cells.

b. Natural Killer cells or NK cells are large white blood cells that, unlike phagocytes, attack cells that have been infected by pathogens, not the pathogen themselves. These cells attack body cells that have been infected by viruses. Since viruses can only replicate in a host cell, killing the host cell also destroys the virus.

Natural killer cells are particularly effective in killing cancer cells and cells infected with viruses. A natural killer cell punctures the cell membrane of its target cell, allowing water to rush into the cell, causing the cell to burst. This is called cytolysis. The NK cells also secrete cytokines that are antiviral and inflammatory in nature.

Keeping Diseases Away Text Book Questions and Answers

Hss Live Biology Chapter 4 Keeping Diseases Away Question 1.
What are the reasons forthe spread of diseases and list out practical suggestions to avoid such situations?

Keeping Diseases Away Question 2.
Expand the list by including pathogenic microorganisms?

Keeping Diseases Away Question 3.
How are pathogens transmitted from one person to another?

Communicable diseases:
Communicable diseases are caused by the invasion of pathogens into the body and are transmitted from one person to another.

Rat fever is a bacterial disease. Bacteria is a prokaryote. They enter the body and multiply through binary fission. The toxins produced by them destroy cells and cause disease.

Hss Live Biology Chapter 4 Keeping Diseases Away Question 4.
What are the measures to be taken to prevent the transmission of rat fever?
For controlling diseases like rat fever, eliminate the vectors and take preventive medicines as per the directions of experts. Disease affected persons must undergo diagnostic tests to confirm their illness and should take proper medicines. Ensure personal hygiene and environmental hygiene.


Analyse the information and figure related to diphtheria and prepare a table

Pathogen Corynebacterium diphtheriae
Body parts affected Mucus membranes of the nose and the throat
Symptoms Fever, throat pain and inflammation the lymp glands of the throat
Transmission of Diseases Cough, sneezing or directly from the infected person to another person

Pathogen Mycobacterium tuberculosis.
Major Symptoms Loss of body weight, fatigue, persistent cough
Transmission of Disease When the patient speaks, coughs or sneezes, the pathogens spread into the air and thereby to others.
Organs/Body parts Affected Tuberculosis mainly affects the lungs. But kidneys, bones, joints, brain etc. are also affected
Treatment Vaccine By administering antibiotics BCG is used as preventive vaccine against tuberculosis.

10th Biology Question 5.
Mode of transmission of other bacterial diseases

Diseases Mode of infection of Pathogenic bacteria
Cholera, Typhoid Through contaminated water
Tetanus Through wounds
Tuberculosis Thorugh air
Anthrax Through contact with animals
Botulism Through stale food
Gonorrhoea, Syphilis Through sexual contact

Virus has the simple structure with a DNA or RNA molecule within a protein coat. Virus has no cell organelles as seen in normal cells. Hence virus multiplies by taking control over the genetic mechanism of the host cells. Viruses infect not only human beings but also plants, other animals and even bacteria.

Nipah Virus And Transmission Of The Disease:

Virus has the simple structure with a DNA or RNA molecule within a protein coat. Virus has no cell organelles as seen in normal cells. Hence virus multiplies by taking control over the genetic mechanism of host cells. Viruses infect human beings, plants, animals and bacteria

AIDS (Acquired Immuno Deficiency Syndrome) is a condition of gradual decrease of immunity by the destruction of lymphocytes by the infection of HIV. HIV enters the body and multiplies using the genetic mechanism of lymphocytes. Hence the number of lymphocytes decreases considerably and reduces the immunity of the body. Various other pathogens which enter the bod^ in such a situation make the condition of AIDS even more fatal

Question 6.
What are the ways by which HIV spreads Write your inferences in science diary by analysing illustration?

Question 7.
How AIDS does not spread

  • By touch, shaking hands, coughing sneezing etc
  • through insects like mosquitoes, house flies etc.
  • by staying together and sharing food.
  • Through the reception of blood and organs contaminated with HIV

Question 8.
Do we need to fear AIDS patients? What should be our attitude towards them Discuss?
Unlike other diseases, AIDS can be completely prevented by taking right precautions. AIDS is not a communicable disease. Therefore AIDS virus will not be transferred through social contacts such as touching or sharing food, and water. It is transmitted by sexual contact transfusion of blood, using unsterilized needle and syringe, use of blade and the razor in the barbershops and mother to foetus. So show positive attitude towards AIDS patients. To provide adequate care and attention to AIDS patients and make their relatives and.the public aware of it.

Hepatitis is a liver diseases it is also caused by vims. Inflammation of the liver is its major symptom. When the flow of the bile secreted by the liver is blocked, an increase in the level of bile pigment, bilirubin in blood is noticed. This imparts dark yellow colour to the mucous membrane, white portion of the eyes and the nails. This is the external symptom of diseases.

Mode of transmission:
Disease gets transmitted through contaminated food and water blood components and excreta of the patient.

Kerala Syllabus 10th Standard BiologyQuestion 9.
Complete the table of viral diseases and its modes of transmission

a) Through body fluids
b) Chickenpox, Dengue fever
c) Chikungunya, Dengue fever.
d) Rabies

Fungi are of various types. Some fungi are pathogenic. The toxins produced by the fungi cause diseases. Ringworm, Athletes’ foot are fungal diseases.
Given below is the table showing fungal diseases, symptoms and mode of infection

Diseases Caused By Protozoa

Protozoans are unicellular eukaryotes. Malaria is an. example for diseases caused by protozoa.

Question 10.
Prepare a note by analysing illustration and information on malaria.

Malaria is caused by the protozoan, plasmodium. Malaria is spread by female Anopheles mosquito. High fever with shivering and profuse sweating are the major symptoms of malaria. Other symptoms include headache, vomiting diarrhoea, anaemia etc. Hoste is man. Symptoms repeat intermittently

Filariasis is caused by filarial worms that are spread by Culex mosquito. The worms stay in the lymph ducts and obstruct the flow of lymph by blocking the ducts. This causes swelling in the lymph ducts in the legs.

Question 11.
What are the preventive measures to be taken against communicable diseases? What is the significance of observing “Dry Day” in schools and at home? Discuss.
Keep the surroundings clean

  • Personal hygiene
  • Community hygiene
  • Eradication of mosquitoes
  • Awareness programme – Poster, Rally.

Our carelessness and unclean surroundings are the main reason for the spreading of these types of contagious diseases. Contaminated surroundings promote the multiplication of pathogens and vectors. So it is necessary to avoid situations that lead to communicable diseases. So observing dry day is most effective remedial measure.

Question 12.
Are diseases caused only by pathogens?
Are they caused by other factors too?
No, the diseases are not caused only by pathogens. Many diseases are caused by other factors too. The other factors are

Question 13.
Observe the illustration. Give example of diseases for each category.


Lifestyle diseases Cancer, Diabetes, Stroke
Genetic diseases Haemophilia, Sickle cell, anaemia
Deficiency of nutrients Anaemia, Goiter, Marasmus
Occupational diseases Pneumoconiosis, Silicosis, Asbestosis.

Genes regulate cellular activities. The defects in genes also bring about diseases. Such diseases are called genetic diseases. Haemophilia, sickle cell anaemia etc., are examples of genetic diseases.

Haemophilia is the condition that excess blood is lost even through minorwoundsdueto synthesis of protein fails when the genes that control protein synthesis become defective. As haemophilia is a genetic disease a complete cure is not possible. Temporary relief is brought in by injecting the deficient protein identified through clinical diagnosis.

Some social organisations are working for haemophlilia patients who need special care and attention. These organisations volunteerto provide adequate care to haemophilia patients and make their relatives and the public aware of it.

Sickle cell Anaemia:
The defects of genes may also cause deformities in the sequencing of amino acids which are the building blocks of haemoglobin. As a result of this, the structure of haemoglobin changes and this in turn decreases its oxygen carrying capacity.

Question 14.
Why do haemophilia patients loose blood excessively, through minor wounds?
Bloods clots with the help of some proteins present in blood plasma. The synthesis of proteins fails when the genes that control protein synthesis become defective. Hence excess blood is lost even through minor wounds.

Question 15.
How does the deformity of red blood cells in sickle cell anaemia patients affect their body?
The changes occur in the structure of haemoglobin in red blood cells is cause of these diseases. The blood cells bend like sickle. Decreases the oxygen-carrying capacity of red blood cells. The RBCs in the shape of sickle aggregate and block the flow of blood through the blood vessels.

Cancer is caused by the uncontrolled division of cells and their spread to other tissues. The normal cell gets transformed into cancerous cells when the control system of cell division fails. Various reasons such as environmental factors, smoking, radiations, virus, hereditary facts and alternations in genetic material lead to the transformation of normal cells into cancerous cells.

Question 16.
Early identification of cancer helps the treatment easy. What are the treatments for cancer patients?
Surgery, chemotherapy, radiation therapy etc. are used in the treatment of cancer.

Question 17.
Many voluntary organisations are involved in our society to offer better care to cancer patients. What are the importance of such activities?
These organisations offer better care to cancer patients. Give love and care to the patients. Give nutritious food, clothes, medicine and proper care. This helps make awareness about people.

Lifestyle diseases are caused by unhealthy living style. The changes in food habits, lack of physical exercise, stress, bad habits like consumption of alcohol, drug abuse, smoking etc. lead to various lifestyle diseases

Question 18.
Prepare a table showing lifestyle disease and their causes.

Diabetes Deficiency of insulin or its malfunctioning
Fatty Liver Deposition of excess fat in the liver
Stroke Rupture of blood vessels in brain, block of blood flow
Hypertension Decrease in the diameter of arteries due to deposition of fat
Heart Attack Block of blood flow due to deposition of fat in coronary arteries.

Question 19.
Observe the following illustration on some of the health problems associated with smoking

Prepare a poster showing slogans against the habit of smoking.

  • Cigarette smoking is injurious to health.
  • Smoking is a social crime.
  • Quit smoking, it kill you

Question 20.
Collect more information on the bad effects of smoking and write it in your science diary.
Cigarette smoke contains poisonous substances. They badly harm the respiratory system. Carcinogens present in the smoke cause cancer in respiratory system. Bronchitis and Emphysema are diseases prevalent in smokers. Tobacco smoke injures every part of the respiratory system. It injures the lining of the nose, throat, trachea and lungs. Tobacco smokers, therefore , face a higher risk of lung cancer that non-smokers.

Question 21.
Prepare table showing animal diseases and their pathogen.

Disease Pathogen
Anthrax, Inflammation of udder (Mastitis) Bacteria
Foot and mouth diseases Virus

Keeping Diseases Away Let Us Assess

Question 1.
Which among the following is not a bacterial disease?
a) Tuberculosis
b) Nipah
c) Diphtheria
d) Anthrax
b) Nipah

Question 2.
“Food safety will be adversely affected with the spread of plant diseases”.
a) Do you agree with this statement? Why?
b) Give two examples of plant diseases?
a) Yes, I agree with this statement. We cannot make agriculture profitable by the maximum utilisation of farmland. The main reason for decreasing food production is only the plant diseases.
b) (1) Blight diseases
(2) Bunchy top of banana

Question 3.
Prepare a pamphlet including the major measures to be taken to prevent rat fever.
For controlling diseases like rat fever, eliminate the vectors and take preventive medicines as per the directions of experts. Disease affected persons must undergo diagnostic tests to confirm their illness and should take proper medicines. Ensure personal hygiene and environmental hygiene.

Question 4.
What is the importance of vaccination in preventing diphtheria?
Antitoxins which act against the toxins produced by Corynebacterium diphtheria are used to protect the uninfected cells. But if the disease becomes severe the patient cannot be recovered through medication. So vaccination is the best preventive method.

Question 5.
What health habits should be adopted to prevent lifestyle diseases?

  • Avoid the use of food containing higher level of fat and salt.
  • Control diabetes and high blood pressure time to time
  • Take steps to minimize mental pressure.
  • Avoid smoking and alcohol consumption.
  • Have regular exercise.

Keeping Diseases Away Extended Activities

Question 1.
Prepare a checklist and collect information on various lifestyle diseases. Find out the lifestyle diseases that are seen commonly. (Hints: Preparing a questionnaire, data collection and analysis)

Question 2.
Prepare and exhibit posters highlighting the fact that social hygiene is as important as personal hygiene.

Keeping Diseases Away More Questions and Answers

Question 1.
Complete the table


Disease Pathogens Vector of the pathogen
Dengue gever Dengue virus Aedes mosquitoes
Chikungunya CHIKV Aedes mosquitoes
Malaria Protozoa Anopheles mosquitoes
Filariasis Filarial worms Culex mosquitoes

Question 2.
List the diseases spread by the mosquitoes? Point out the preventive measure.
Malaria, Dengue fever, Filariasis, Chikungunya, Yellow fever, Japanese encephalitis, Zika fever etc. are the diseases spread by mosquitoes.
Preventive measures

  • Avoid the circumstances leading to spread of mosquitoes
  • Observe “Dry Day” once in two weeks.
  • Keep our surroundings clean.
  • Practice use of measures like mosquito nets.
  • Avoid the habit of littering.
  • Do not throw garbage’s in the water bodies.

Question 3.
Suppose cholera is being spread in a particular locality. Suggest the precautionary measures to be adopted in the locality?
The bacteria causing cholera spread through water or housefly in the dirty atmosphere. Therefore the first and foremost requirement is to keep the surroundings neat and clean Facilitates of clean atmosphere, personal hygiene and pure drinking water should be made available in the cholera affected locality.

Question 4.
Expansion of DOTS is …………..
Directly observed treatment short course.

Question 5.
Complete the table given below.

Disease Symptom Mode of infection
a) ring Worm …………… …………..
b) ………….. ………….. …………….

a) Ringworm round red blisters on the skin spread through contact
b) Athletes foot appearance of reddish scaly on the sole of the foot and between the toes Contact with contaminated water and soil

Question 6.
During rainy season Athletes’ foot is common’. Give reason?
Athlete’s foot is a skin disease caused by certain types of fungi. Pathogens enterthroughthe toes when they come in contact with contaminated water and soil. That is why in rainy season it is very common

Keeping Away Question 7.
Given below is the graph showing the result of a health survey conducted by students in a locality. Analyse the graph and answerthe following questions.

a) Identify the most common disease in that locality?
b) What are the symptoms of that disease?
c) Name the pathogen of each category of the disease.
a) Tuberculosis
b) Loss of body weight, fatigue, persistence cough
c) Dengue fever, chikungunya-virus Tuberculosis, cholera – Bacteria

Kerala Syllabus 10th Standard Biology Question 8. Compare Haemophilia and Sickle cell anaemia?

10th Standard Biology Question 9. What does the following picture indicate?

Sickle cell Anaemia. Red blood cells bend like a sickle so the oxygen carrying capacity of red blood cells decreases.

Question 10.
Indications about a disease are given in the box. Identify the disease
1. Defects of genes cause deformities in the sequencing of amino acids which are the building blocks of Haemoglobin.
2. Red blood cells bend like a sickle.
3. Decreases the oxygen-carrying capacity of red blood cells.
Sickle cell Anaemia.

Question 11.
Smokers and tobacco users are not only subjected to cancer but also many other defects. Evaluate the statement?
The statement is correct. There is possibility of diseases like stroke, bronchitis, hypertension etc. apart from cancer in case of frequent users of tobacco products.

Question 12.
Point out some lifestyle habits to prevent heart diseases.

  • Avoid the use of food containing higher level of fat and salt.
  • Control diabetes and high blood pressure time to time
  • Take steps to minimize mental pressure.
  • Avoid smoking and alcohol consumption.
  • Have regular exercise.

Question 13.
“In smokers the ability of blood to receive oxygen is low”.
a) What is the reason for this?
b) Name any two toxic substances present in tobacco? (Model 2015)
a) A stable compound, ‘carboxyhaemoglobin’, forms in blood and therefore the transport of oxygen reduces.
b) Nicotine, CO, benzopyrin, Carcinogens (any two)

Question 14.
Analyse the graph showing the diseases that affected the crops in John’s-field and answer the following questions.

a) Identify the most affected crop based on the inference on most prevalent disease.
b) Name the causative agents of the diseases A and C.
c) Which type of insects spread the disease B and D. (Model 2015)
a) Paddy
b) Quickwilt- Fungus, Blight disease – Bacteria
c) Aphids

Question 15.
Match the column B and C with column A.


Question 16.
Diseases are caused not only by micro organisms. Many of the diseases are caused by bad habits”.
a) Give two suitable examples for the statement given.
b) Substantiate the statement based on the topic habits and diseases. (March 2014)
a) Smoking, use of drugs, use of alcohol (any two)
b) Side Effects (three each)

Question 17.
Observe the part of an awareness notice given below:

1. Avoid unprotected sexual relationship
2. Avoid unsterilized injection needles
a) Identify the disease.
b) How unsterilized injection needles transmit this disease? (March 2014)
b) Unsterilized needles used by an AIDS patient contain blood in which HIV present. Transmission through body fluid.

Question 18.
Given below is a graphical representation of the data of individuals who came for treatment on July 2013 in a Government Hospital, Kerala. Analyse the graph and answer the following questions.

a) Which disease is common in this locality?
b) Write a major symptom of this disease.
c) Prepare two posters to be exhibited in an awareness programme against this disease. (March 2014)
a) Dengue Fever
b) Blood platelet count decreases internal bleeding and red rashes on the chest or face.
c) Two posters

Question 19.
The blood test of a patient appeared the red blood cells as shown in the figure

a) Identify the affected disease.
b) What are the reasons for this disease?
c) Write a symptom of this disease.
d) How does this disease affect our body? (Model 2013)
a) Sickle cell anaemia.
b) Structural deformity in the haemoglobin molecules of the red blood cells due to genetic disorder
c) RBC become sickle-shaped cells.
d) Anaemia due to decreased level of oxygen in the blood and therefore difficulty in doing hard work.

Question 20.
Observe carefully the graph illustrating the data of a survey conducted in certain towns by the Health Department. Analyse the graph and answer to the following questions.

a) Which type of mosquito is dominated in town A?
b) Identify the disease which is likely to be spread in town B. Name the pathogen which causes that disease.
c) Write an important symptom of that disease. (Model 2013)
a) Culex mosquitoes
b) Malaria, Protozoa.
c) Severe fever recurring at interval and severe headache.

Question 21.
Name any two bacterial diseases. (March 2012)
Any two, For example- Cholera, Typhoid, Rat fever, Leprosy.

Question 22.
Given below are symptoms of a disease.
i) RBC undergo change in shape and transform into sickle-shaped cells.
ii) Oxygen transport to the tissue is reduced.
a) Identify the disease
b) What is the reason for this disease? (March 2012)
Sickle cell anaemia, a genetic disorder which deforms the RBC and they become crescent shaped and content of haemoglobin in them is highly reduced.

Keeping Diseases Away Questions and Answers

Question 1.
What do you mean by disease?
A disease is a particular abnormal condition, a deviation from the normal functioning of the body systems.

Question 2.
Qn. 2
The causal’Study of disease is called ……………

Question 3.
Name some pathogens?
Virus, bacterim,fungus, protozoa and worms.

Question 4.
Name some communicable diseases?
Dengue fever, chikungunya, chickenpox, cholera, Anthrax etc.

Question 5.
Write 2 slogans for the poster in association with mosquitoes day on August 20.

Question 6.
Prepare a flow chart showing the mode of infection of dengue fever.

Question 7.
Given belowthe picture of aedes mosquito name two diseases caused by this mosquito.

Denque fever, chikungunya

Question 8.
What is the structure of a virus?
Virus has the simple structure with a DNA or RNA molecule within a protein coat.

Qn. 9
Name some viral diseases?
Dengue fever, chikungunya, Ebola, chickenpox, SAARS, AIDS, Rabies.

Qn. 10
How does vims multiply?
Virus multiplies by taking control over the genetic mechanism of host cells. During this process, the cell gets damaged leading to disease.

Qn. 11
“Virus requires a host cell to get multiplied” Give reason?
Virus has no cell organelles as seen in normal cells It has the simple structure with a DNA or RNA molecule within a protein coat.

Question 12.
Identify the picture.

HIV virus (Human Immuno Deficiency Virus)

Question 13.
Expansion of AIDS?
Acquired Immuno Deficiency Syndrome

Question 14.
Expansion of HIV?
Human Immuno Deficiency vims

Question 15.
What is AIDS?
AIDS (Acquired Immuno Deficiency Syndrome) is a * condition of gradual decrease of immunity by the destruction of lymphocytes by the infection of HIV (Human Immuno Deficiency Virus). HIV enters the body multiplies using the genetic mechanism of lymphocytes.

Question 16.
Read this newspaper cutting
“AIDS-affected children were denied admission in School”
What is your opinion about the decision of the school authorities? Is AIDS a communicable disease?
The decision taken by the school authority to refuse admission for AIDS-affected children is totally wrong. This is because AIDS is not a communicable disease. Therefore AIDS vims will not be transferred through touching or sharing food, water, air etc.

Question 17.
Do you think that AIDS will spread through mosquitoes and houseflies?

Question 18.
The following red ribbon is the international symbol to represent a disease identify the disease?

Question 19.
What are the precautions that can be taken to prevent the spread of virus causing AIDS?
Take precaution before receiving blood. Do not use syringe and needles already used. Have safety in sexual relationship.

Question 20.
Though bacteria are generally helpful, some of them are harmful. How?
Bacteria multiply through binary fission immediately after entering the body. The toxins produced by these bacteria damage living cells and thereby bring
about diseases.

Question 21.
Name certain bacterial diseases?
Cholera, Typhoid, Tetanus, Tuberculosis, Anthrax, Botulism, Gonorrhoea and Syphilis.

Question 22.
Complete the table of bacterial disease

a) Cholera, Typhoid
b) Through wounds
c) Tuberculosis
d) Anthrax
e) Botulism
f) Through sexual contact

Question 23.
AIDS is a viral disease caused through sexual relations. Give examples of two bacterial diseases that are caused by similar manner?
Gonorrhoea, Syphilis

Question 24.
Name a bacterial disease spread through air?

Question 25.
……………… is a bacterial disease that affected the lungs.

Question 26.
Identify the bacteria which causes Tuberculosis?
Mycobacterium tuberculosis.

Question 27.
………….. treatment is recommended for tuberculosis by World Health Organisation.

Question 28.
What are the major symptoms of Tuberculosis?
Loss of body weight, fatigue, persistent cough are the major symptoms of tuberculosis.

Question 29.
Tuberculosis affects the lungs only’. Do you agree with this statement? Substantiate your answer?
Tuberculosis mainly affects the lungs. It also affects kidneys, bones, joints, brain etc by this disease.

Question 30.
…………… is the vaccine used against tuberculosis across the world
BCG vaccine

Question 31.
DOTS treatment is given to which category of patients?
Patients suffering from Tuberculosis.

Question 32.
Write slogans to give awareness for controlling tuberculosis?

  • Test your sputum if you have prolonged cough fora couple of weeks.
  • Take BCG vaccination immediately after the birth of children.

Question 33.
Name a bacterial disease which can be spread through castles?

Question 34.
What is Botulism?
Food poisoning caused by the growth of bacteria in improperly sterilized tinned meats and other preserved foods.

Question 35.
Give examples of fungal diseases?
Ringworm. Athletes’ foot

Question 36.
How does fungal diseases spread?
Fungal diseases spread through contact.

Question 37.
How does fungi cause diseases?
The toxins produced by the pathogenic fungi cause diseases.

Question 38.
Malaria is caused by
The protozoa plasmodium

Question 39.
Vector of malaria disease?
Female Anopheles mosquitoes.

Question 40.
Mention the symptoms of malaria?
High fiver with shivering and profuse sweating are the major symptoms of malaria. Other symptoms include headache, vomiting, diarrhoea, anaemia etc.

Question 41.
Filariasis is spread by mosquitoes.
Culex mosquitoes

Question 42.
Filariasis is caused by worms.
Filarial worms

Question 43.
Observe the figure and answer the following questions.
a) Name the disease?
b) Pathogen?
c) Vector?
d) How to prevent the disease?

a) Filariasis
b) Filarial worms
c) Culux mosquitoes
d) Mosquito Control

Question 44.
Find the odd one out
a) Dengue fever, malaria, rabies, filariasis
b) Dengue fever, Rabies, chikungunya, Malaria,
a) Rabis – rabies spread through animals, others spread through mosquitoes,
b) Malaria – Malaria is caused by protozoa, others are caused by virus.

Question 45.
Compare Malaria and filariasis with the help of the following indicators.
1. Pathogen
2. Vector
3. Symptoms

Malaria Filariasis.
Pathogen Protozoa plasmodium Filarial worms
Vector Anopheles mosquito Culex mosquito
Symptoms High fever with shivering headache, vomiting diarrhoea sweating obstruct the flow of lymph by blocking the lymph ducts and that causes swelling in the lymph ducts in the legs

Question 46.
Give reasons “The legs of Filariasis patients’ swell?
Because the filarial worms stay in the lymph ducts and obstruct the flow of lymph by blocking the ducts. This causes swelling in the lymph ducts in the legs.

Question 47.
Give example for a few diseases which are not communicable to person to person?
Haemophilia, Sickle cell Anaemia, Cancer, Diabetes, Stroke.

Question 48.
Complete the word relation.
Diabetes: Lifestyle disease
Haemophilia: …………….
Genetic disease

Question 49.
Differnciate Anaemia and Sickle cell Anaemia.
Anaemia is a condition that develops when your blood lacks enough oxygen content due to the lack of iron content in the red blood cells. On the other hand, sickle cell anaemia is a serious inherited blood disorder where the red blood cells which carry oxygen around the body, develop abnormally. In cause of sickle cell anaemia changes occurs in the structure of haemoglobin in red blood cells. Red blood cell bend like a sickle and hence it is called sickle cell anaemia.

Question 50.
The condition that excess blood is lost even through minor wounds is known as ……………

Question 51.
World Haemophilia Day is observed in ……………….
April 17

Question 52.
What do you mean by Haemophilia? What causes it? Is it curable by treatment?
Haemophilia is the condition that excess blood is lost even through minor wounds due to synthesis of protein fails when the genes that control protein synthesis become defective. As haemophilia is a genetic disease a complete cure is not possible. Temporary relief is brought in by injecting the deficient protein identified through clinical diagnosis.

Question 53.
Why is sickle cell anaemia called a “Sickle disease”?
In case of sickle cell, anaemia changes occur in the structure of haemoglobin in red blood cells. Red blood celsl bend like a sickle and hence it is called sickle cell anaemia.

Question 55.
Compare a patient of sickle cell anaemia with a healthy person?
Compared to a healthy person, of a person having sickle cell anaemia decreases the oxygen carring capacity.

Question 56.
How does smoking affect the following organs? (Brian, Lungs and Heart)

Question 57.
Identify the health issues caused by alcohol consumption?
1) Causes kidney disease, ulcers, liver cancer, fatty liver etc.
2) Contributes to high blood pressure and stroke
3) Increases blood sugar levels which makes diabetes worse.

Question 58.
Give examples for diseases caused by unhealthy lifestyle?
Diabetes, fatty liver, high blood pressure, stroke, heart attack.

Question 59.
‘India – world capital of Diabetes’ – Explain this news headline?
Due to unhealthy food and lifestyle habits, the number of diabetic patients sharply increased in India. Apart from over consumption of food, absents of adequate exercise also contribute to diabetes.

Question 60.
‘Diabetes and high blood pressure are silent killers’ Why?
Diabetes and hypertension can damage the kidneys. It increases the risk of blindness and dementia. Untreated hypertension increases the risk of heart disease and stroke. Due to these reasons, diabetes and hypertension are called silent killers.

Question 61.
Name some disease that affects the cattle?
Anthrax, Foot and mouth disease, Inflammation of udder.

Question 62.
………………….. is the pathogen of Anthrax
Bacillus Anthracis (Bacteria)

Question 63.
Complete the table of diseases that affect the domestic animals.

a) Virus – High fever, Blisters in the mouth and on feet, Drop in milk production, weight loss
b) Sudden fever, diarrhoea, mouth sores, nausea and vomiting
c) Inflammation of udder – Bacteria – swelling of udder, drop in milk production.

Question 64.
Complete the word relation?
Cattle : Antrax: Bacteria
Cattle: Foot and mouth diseases: ………………

Question 65.
Prepare a table showing important plant diseases and their pathogen?

Blight disease of paddy, Wilt disease of brinjal Bacteria
Mosaic disease in peas and tapioca, bunchy of banana Virus
Quickwilt in pepar Budrot of coconut Fungus

Question 66.
Complete the word relation
Paddy: Blight: Bacteria
Coconut : Budrot:………..

Question 67.
………………. is a viral disease which spreads from wild animals to human beings.

Question 68.
Where and when did Ebola was first idientified?
Central Africa in March 2014.

Question 69.
Point out the symptoms of Ebola?

  • Severe fever
  • Muscle pain
  • Vomiting
  • Diarrhoea
  • Internal and external bleeding

Keeping Diseases Away SCERT Questions and Answers

Question 1.
Polluted surroundings and stagnation of water lead to the multiplication of mosquitoes. Mosquitoes carry many diseases to man. One such disease results in the considerable decrease in the number of platelets.
a) Name the disease.
b) Which microbe causes this disease? (Question Pool 2017)
a) Dengue
b) Dengue virus

Question 2.
Rearrange columns B & C suiting the pictures in column A. (Question Pool 2017)

i- b, R
ii – c, P
iii – a, Q

Question 3.
Choose the statements related to virus from those given below.
a) Multiplies by binary fission.
b) Has a simple structure with a DNA or RNA molecule within a protein coat.
c) Toxins produced by them damage living cells.
d) Multiplies by taking control over the genetic mechanism of host cells. (Question Pool 2017)
b, d

Question 4.

Shown above is one of the presentation slides prepared by Pradeep, as part of the International year of Microbes.
a) Which is the microbe mentioned in the slide?
b) Which disease is caused by this microbe?
c) How does this affect the immunity of the body?
b) – AIDS
c) 1. Multiplies using the genetic mechanism of lymphocytes.
2. Considerable decrease in the number of lymphocytes.
3. Disrupts immunity.

Question 5.
Analyse the statements related to the spread of AIDS and classify them suitably.
a) Through mosquitoes & houseflies.
b) Through body fluids.
c) Through extramarital sexual contact.
d) By touch, shaking hands, coughing etc.
e) From HIV infected mother to foetus.
f) When you sit near an HIV infected friend in the school.


Situations where HIV spreads Situations where HIV does not spread
(b) (a)
(c) (d)
(e) (f)

Question 6.
Complete the illustration of bacterial diseases given below. (Question Pool 2017)

A – Tuberculosis
B – Contaminated water/food
C – Tetanus

Question 7.
An interview with the doctor of the Primary Health Centre regarding tuberculosis, organised by the Health Club is given below. What is your explanation for the questions asked by the children?
a) Which bacteria causes this disease.
b) Write two symptoms of this disease.
c) Name the vaccine used to prevent tuberculosis. (Question Pool 2017)
a) Mycobacterium tuberculosis
b) Loss of body weight, Fatigue, Persistent cough.
c) BCG

Question 8.
a) What is common between the diseases given in the box?
b) Pick out the odd one. Justify. (Question Pool 2017)
a) Diseases spread through air
b) Tuberculosis is a bacterial disease and rest all virus diseases

Question 9.
The result of a survey conducted by the Health Department on mosquito-borne diseases is shown in the graph. Analyse the graph and answer the questions.

a) Which disease affects more number of people?
b) Write symptoms of the disease B.
c) Suggest suitable measures to prevent the spread of the diseases shown in the graph. (Question Pool 2017)
a) Filarial worm
b) High fever with shivering, profuse sweating, headache, vomiting, diarrhoea, anaemia etc.
c) Dengue fever, Malaria, Filariasis are the diseases spread by mosquitoes. So avoid the circumstances leading to spread of mosquitoes. Observe ‘Dry Day’ once in two weeks, keep our surroundings clean, practise use of measures like mosquito nets.

Question 10.
Make suitable pairs using the information given in the box.
Deficiency of nutrients,
Genetic. (Question Pool 2017)

Question 11.
Anjanagets wounded on her foot while playing with her friends. Due to continuous bleeding, her parents take her to the hospital. The doctor’s diagnosis after thorough investigation is given below.
“This has happened as the blood is not clotting. This is a genetic disease.”
a) What is Anjana’s disease?
b) How can temporary relief be brought about for the disease? (Question Pool 2017)
a) Haemophilia
b) Injecting the deficient protein helps in blood clotting.

Question 12.
Change in the shape of RBC due to genetic disease is shown in the figure.

a) Name the disease shown in the figure.
b) How does the deformity of RBC affect the body?
a) Sickle-cell anaemia
b) 1. Decreases the oxygen-carrying capacity of red blood cells.
2. Sickle-shaped RBC aggregate and block the blood flow through blood vessels.

Question 13.
Identify the given symptoms and tabulate them with the name of the disease as headings.
a) The deformity in the sequencing of amino acids of haemoglobin due to the defect of genes.
b) The defect in the production of protein for blood clotting.
c) Excess loss of blood even though a minor wound.
d) The oxygen-carrying capacity of red blood cells decreases. (Question Pool 2017)

Haemophilia Sickle cell anaemia
b a
c d

Question 14.
You are invited to prepare a presentation slide for the Cancer awareness class, conducted by the Health Club. What explanation will you give to the ideas given below?
a) The disease cancer
b) Reasons for cancer
c) Treatment for cancer (Question Pool – 2017)
a) Cells undergo uncontrolled division and spread to other tissues.
b) Environmental factors, smoking, radiations, virus, hereditary factors alteration of genetic materials, chemical substances.
c) Chemotherapy, surgery, radiation therapy

Question 15.
An early diagnosis of the disease is crucial in the treatment of cancer. Why? (Question Pool 2017)
It is difficult for the patients to recover if the disease becomes severe.

Question 16.
Choose the ones related to lifestyle diseases from those given below.
a) Hereditary factors
b) Lack of exercise
c) Mental stress
d) Environmental factors ‘
e) Change in food habits
f) Alcoholism, smoking
b, C, e, f

Question 17.
Arrange the indicators given in column B suitable to column A.

Disease Cause
A. Stroke i. deficiency of insulin or its malfunctioning.
B. Diabetes ii. deposition of excess fat in the liver.
C. Fatty liver iii. blockage of blood flow in the brain.
iv. decrease in the diameter of the artery due to deposition of fat.

Question 18.
Some health issues due to smoking are given below. Name the affected organ. (Question Pool 2017)

A – brain
B – lungs
C – any organ

Question 19.
Make a poster to provide awareness about the health issues due to smoking. (Question Pool 2017)
Smoking is injurious to health

Question 20.
Classify the diseases given below into animal diseases and plant diseases. (Question Pool 2017)
Blight disease,
Quick wilt,
Foot and
mouth disease,
Inflammation of udder

Animal diseases Plant diseases
Anthrax Blight disease
Foot and mouth disease Quick wilt
Inflammation of the udder Bunchy top of banana

Question 21.
A study of the Agriculture Department on plant diseases in a panchayath is given below as a graph. Analyse this and answer the questions. (Question Pool 2017)

a) Which is the mostly affected crop?
b) Name the disease that affects pepper.
c) What are the fungal diseases that affected the plants of that area?
a) Paddy
b) Quick wilt
c) Bud rot quick wilt

Question 22.
Analyse the slogan given in the placard and answer the questions

a) What is health?
b) What should be our attitude to patients? (Question Pool 2017)
a) The complete physical, mental and social wellbeing of a person.
b) Compassion, mercy, sympathy, empathy, pity, service mindedness and helping mentality etc.

Question 23.
Given below is a doubt raised by Asna when she notices that lungs are mentioned in an advertisement against smoking.
“Does smoking affect only the lungs?”
As a science student, what explanation will you give for this question? (Question Pool 2017)

Question 24.
Nandu: Smoking causes cancer.
Mahesh: Smoking causes lifestyle diseases. Analyse the possibilities of these two statements and write your interpretation. (Question Pool 2017)
The statements of both of them are correct. Smoking causes cancer and lifestyle diseases like stroke and hypertension.

Question 25.
Choose the correct statement.
a) Malaria, Filariasis, Cholera etc. are spread by mosquitoes.
b) Anthrax & Rabies are transmitted from animal to man.
c) Tuberculosis, SARS and chickenpox spread through air.
d) Syphilis, Gonorrhoea and Botulism spread (Question Pool 2017)
b, c

Question 26.
Analyse the diseases given below and arrange them suitably in the boxes provided,
a. Blight
b. Botulism
c. Ebola
d. Inflammation
e. Quick wilt
f. Foot and of udder mouth disease

Question 27.
Classify the diseases given in the box suitably,
a. Anthrax
c. Bud rot
d. Foot and mouth
e. Athletes foot
f. Tetanus disease
Bacteria – (a), (f)
Virus – (b), (d)
Fungus – (c), (e)

Question 28.
Classify the diseases given below based on the mode of transmission. (Question Pool 2017)
2. Chikungunya,
3. AIDS,
4. Gonorrhoea,
5. Malaria,
6. Dengue,
7. Syphilis,
8. Chickenpox,
9. Tuberculosis

Through air Through sexual contact Through Mosquitoes
1. SAARS 1. Syphilis 1. Dengue fever
2. Chickenpox 2. Gonorrhoea 2. Malaria
3. Tuberculosis 3. AIDS 3. Chikungunya

i. Blight a. Virus P. Pepper
ii. disease b. Bacteria Q. Paddy
ii. Quick wilt c. Fungus R. Banana

Question 30.
A few characteristic features of microorganisms are given below. Analyse them and complete the illustration. (Question Pool 2017)

A – (iii)
B – (ii)
C – (iv)

Question 31.
Cause of all diseases are microorganisms. All microorganisms are pathogens. Evaluate this statement and justify your answer giving suitable examples. (Question Pool 2017)

  • Do not agree with this statement.
  • Diseases occur without pathogens also, etc. diabetes/stroke/ cancer etc.
  • All micro organises are not pathogens. There are useful microorganisms also.

eg: Bacteria seen in the intestine and skin.

Question 32.
Read the statements and answer the questions given below.

a) Identify the disease?
b) Identify the pathogen?
c) Give scientific explanation against the tendency of isolating these persons from the society?
b) HIV (Human Immunodeficiency Virus)
c) This tendency is wrong. HIV spreads only through body fluids, but not by touching, biting, kissing, sneezing, cough, drinking or eating food.

Question 33.
“Unhealthy lifestyle invites diseases”. Justify the statement with examples. (Orukkam 2017)
Unhealthy lifestyle may cause diseases like diabetes, fatty liver, hypertension, stroke and heart attack. Smoking may cause lung cancer, bronchitis, emphysema and decrease in the ability of heart.

Question 34.
The extent of the disease affected crops in Rajesh’s farm is represented graphically. Analyse the graph and answer the given questions. (Orukkam – 2017)

a) Identify the most affected crop.
b) Identify the least affected crop.
c) Pair the pathogen and diseases of affected crops,
a) Banana
b) Pepper
c) 1. Blight – Bacteria
2. Wilt – Bacteria
3. Bunch top – virus
4. Quick wilt – Fungus

Question 35.
a) What is cancer?
b) How normal cells get transformed into cancerous cells?
c) What are the methods adopted in cancer treatment? (Orukkam 2017)
a) Cancer is the condition by which uncontrolled division of cells and their spread to other tissues
b) Environmental factors, smoking, radiations, viruses, hereditary factors and alteration in genetic materials.

Question 36.
The symptoms of a communicable disease are given below.
Loss of body weight, fatigue, persistent cough
a) Name the disease?
b) Identify the pathogen?
c) How this disease is transmitted? (Orukkam 2017)
a) Tuberculosis
b) Mycobacterium tuberculosis (Bacteria)
c) Through air

Treatment of Fever in Adults

Because fever helps the body defend against infection and because fever itself is not dangerous (unless it is higher than about 106° F [41.1° C]), there is some debate as to whether fever should be routinely treated. However, people with a high fever generally feel much better when the fever is treated. Plus, people with a heart or lung disorder and those with dementia are considered to be at particular risk of dangerous complications, so when they have a fever, it should be treated.

Drugs used to lower body temperature are called antipyretics.

The most effective and widely used antipyretics are acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin , ibuprofen , and naproxen .

Typically, people may take one of the following:

650 milligrams of acetaminophen every 6 hours (not to exceed 4,000 milligrams in 1 day)

200 to 400 milligrams of ibuprofen every 6 hours

Because many over-the-counter cold or flu preparations contain acetaminophen , people must be careful not to take acetaminophen and one or more of these preparations at the same time.

Other cooling measures (such as cooling with a tepid water mist and using cooling blankets) are needed only if the temperature is about 106° F (41.1° C) or higher. Sponging with alcohol is avoided because alcohol can be absorbed through the skin and may have harmful effects.

People who have a blood infection or who have abnormal vital signs (such as low blood pressure and a rapid pulse and breathing rate) are admitted to the hospital.

Rare Disease Database

NORD gratefully acknowledges Elena Kovacova, PhD, Department of Animal Physiology & Ethology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic, for assistance in the preparation of this report.

Synonyms of Q fever

Subdivisions of Q fever

General Discussion

Q fever is an infectious disease that is spread by the inhalation or ingestion of a bacterium known as Coxiella burnetii, which belongs to the order of Legionellales. C. burnetii is spread mainly by breathing contaminated air or eating or drinking a contaminated food. Farm workers, especially those who work with animals, people who work in slaughterhouses and veterinarians are especially vulnerable to this disease. Because infection can occur as a result of airborne transmission and the agent is very resistant to environmental conditions, it was included on the list of possible bacteriological weapons. Q fever causes highly variable diseases ranging from acute (often self-limited) infection to fatal chronic infection. Infections that do not cause outward symptoms (subclinical) or no symptoms (asymptomatic) are also common.

Signs & Symptoms

The symptoms of Q fever can vary dramatically from one person to another. Infection can result in no apparent symptoms (asymptomatic) an acute form of disease characterized by a flu-like illness that may go away on its own (self-limited) or can cause other more serious symptoms or a chronic, long-lasting form that can be associated with serious complications. Researchers believe that a variety of factors may influence the severity of Q fever including age, gender, and a person’s general health, including the existence of previous medical conditions (e.g., heart disease).

The acute form of Q fever usually starts approximately two to three weeks after exposure to the bacterium. Acute Q fever is usually characterized by flu-like symptoms such as high fevers, chills, muscle pain (myalgia), and headaches. In some cases, fevers do not occur. Additional nonspecific symptoms can potentially occur including a cough, chest pain, sore throat, a skin rash or gastrointestinal symptoms.

Two other conditions are commonly associated with acute Q fever to varying degrees – pneumonia and inflammation of the liver (hepatitis). Pneumonia is often mild, but potentially can progress to cause acute respiratory distress syndrome (ARDS). Hepatitis may cause abnormal enlargement of the liver (hepatomegaly). More rarely, it can cause yellowing of the skin and the whites of the eyes (jaundice).

Cases of acute Q fever are usually self-limited. However, other symptoms can occur in some affected individuals including inflammation of the muscular wall of the heart (myocarditis), inflammation of the sac-like membrane that surrounds the heart (pericarditis), and the development of a purple skin rash caused by bleeding (hemorrhaging) from tiny blood vessels just below the surface of the skin.

Sometimes acute Q fever presents as neurological disease such as inflammation of the thin membrane covering the brain and spinal cord and the brain itself (meningoencephalitis). In some individuals, acute Q fever can affect the kidneys, thyroids or genitals.

Chronic Q fever may occur months to years after acute disease or may occur without a previous history of acute Q fever. Most cases of chronic Q fever occur in individuals with predisposing conditions such as existing heart valve or blood vessel (vascular) abnormalities or a compromised immune system.

The most common manifestation of chronic Q fever is inflammation the thin membrane lining the inside of the heart and heart valves (infective endocarditis), potentially damaging the heart valves or heart tissue. Affected individuals can develop congestive heart failure, a serious complication in which a limited ability to circulate blood to the lungs and the rest of the body results in fluid buildup in the heart, lungs and various body tissues.

Less commonly, chronic Q fever can present as infection of the bones and joints (osteoarticular infection) such as osteomyelitis or osteoarthritis, vascular infections, chronic hepatitis or chronic pulmonary disease. Osteoarticular infection can cause bone and joint pain. Chronic hepatitis can cause enlargement of the liver or jaundice. Chronic pulmonary disease can cause difficulty breathing (dyspnea) and other respiratory abnormalities.

Individuals with chronic Q fever may also experience a variety of nonspecific symptoms including prolonged fevers (although fevers are often absent), joint pain (arthralgia), muscle pain (myalgia), night sweats, chills, fatigue, and unintended weight loss.

Some individuals with Q fever develop long-term complications (long-term sequelae) such as chronic, persistent fatigue. Some researchers believe that infection with Q fever increases an individual’s risk of developing cardiovascular disease later in life.


Q fever is caused by inhalation or ingestion of the bacterium Coxiella burnetii. People are most often exposed to the bacterium from the milk, urine and feces of infected animals (for example, by inhaling contaminated air in a barnyard). Also, when an infected animal gives birth, the bacteria may be present in high numbers in the amniotic fluid and placenta. Q fever bacterium primarily infects farm animals such as cattle sheep and goats. However, it has been reported in a wide variety of animals including domesticated animals such as dogs and cats.

The C. burnetii bacterium is highly infectious and only a tiny amount is needed to cause disease. The bacterium can survive in the environment for lengthy periods of time because it is resistant to environmental conditions such heat and pressure. It is also resistant to many common disinfectants.

Less common modes of transmission to humans include working in a slaughterhouse, drinking unpasteurized milk, and hunting, slaughtering or dressing infected animals. According to the medical literature, in extremely rare cases, human-to-human transmission has been reported.

The mode of transmission in wild and domestic animals is different from the mode of transmission in humans. Animals become infected with C. burnetii from infected ticks. Originally, Q fever was classified as a rickettsial disease, a group of infectious diseases most often spread to humans from ticks. However, based on DNA-DNA hybridization studies and genome sequencing C. burnetii was placed to the order of Legionellales, which also contains Legionella pneumophila, the bacterium that causes Legionnaire’s disease.

Q fever is a zoonosis, a disease that can be transmitted from animals to humans. C. burnetii is a small, obligate intracellular gram-negative bacterium that can only reproduce within the living cells though the recent findings indicate the possibility of growing C. burnetii also in axenic media. Gimenez staining is very sensitive procedure and often used for visualization of Coxiella and Rickettsia.

Affected Populations

Q fever first became a reportable disease in the United States in 1999. In the ensuing five years, the mean annual incidence of reported cases in the United States was approximately 50. In recent years, cases have been reported in U.S. military personnel serving in Iraq and Afghanistan.

Q fever occurs worldwide and can affect individuals of every racial and ethnic background. The incidence of Q fever is unknown because in many countries it is not a reportable disease. Researchers believe that the infection is underreported. Certain countries have higher incidence rates than other countries, e.g. infections involving hundreds to thousands of human cases occurred recently in the Netherlands.

Q fever has occurred more often in men than women, although researchers attribute this to the fact that more men work in occupations where exposure to C. burnetii bacterium is more likely to occur. Q fever can affect individuals of any age. Although children with Q fever are rarely reported, the diagnosis is probably often missed and the actual incidence of Q fever in children is unknown. Some researchers have speculated that children develop symptoms less often than adults and generally have more mild disease than adults when symptoms do develop.

Q fever was first reported in the medical literature in 1937 by Edward Derrick who named the infection Query Fever.

Related Disorders

Symptoms of the following disorders can be similar to those of Q fever. Comparisons may be useful for a differential diagnosis.

Q fever must be differentiated from other, more common causes of fever, chronic fatigue, weakness, other nonspecific flu-like symptoms and endocarditis. Q fever must also be differentiated from other atypical pneumonias. Atypical pneumonias are a group of diseases in which pneumonia is caused by infection with certain bacteria. This group includes chlamydiosis, bartonellosis, the rickettsial diseases, Legionnaire’s disease, brucellosis, tularemia, and other diseases, namely some viral infections.

The rickettsial diseases are a group of infectious disorder caused by exposure to bacteria belonging to the Rickettsiaceae family. The most common rickettsial disease is Rocky Mountain spotted fever (RMSF), caused by the bacterium Rickettsia rickettsii (R. rickettsii). In most cases, the bacteria responsible for these diseases are though to be carried and transmitted by certain ticks. The severity of the rickettsial diseases varies greatly. Some affected individuals develop usually cause mild symptoms, while others may potentially lead to life-threatening complications. Associated symptoms may include headache, fever, chills, muscle aches (myalgia), joint pain (arthralgia), extreme exhaustion (prostration), and/or a characteristic skin rash. In some cases, additional symptoms may include nausea, vomiting, abdominal pain, and/or other abnormalities. In some severe forms of spotted fever, damage to endothelial cells lining blood vessels may result in tissue injury of the heart, lungs, central nervous system, kidneys, liver, and/or other organs, leading to potentially life-threatening complications. (For more information on this disorder, choose “Rocky Mountain spotted fever” as your search term in the Rare Disease Database).

Legionnaires’ disease is a rare infectious disease that is caused by the bacterium Legionella pneumophila. It got its name from the fact that the first known outbreak occurred at a hotel that was hosting a meeting of the American Legion organization in Pennsylvania in 1976. In that outbreak, it was found that water in the hotel’s air conditioning system was contaminated with the bacteria. Legionnaires’ disease is most often contracted by inhaling contaminated water from sources such as showers and whirlpool baths. Legionnaires’ disease causes severe pneumonia, chills, fevers, cough and a sharp pain in the side of the chest. There is no evidence of human-to-human transmission. (For more information on this disorder, choose “Legionnaires'” as your search term in the Rare Disease Database).

Brucellosis is an infectious disease that affects livestock and may be transmitted to humans. It is rare in the United States (100 to 200 cases occur each year), but occurs more frequently in other parts of the world. The disorder is caused by one of four different species of bacteria that belong to the genus Brucella. Initial symptoms of infection may be nonspecific including fevers, muscle pain, headache, loss of appetite, profuse sweating, and physical weakness. In some cases, the symptoms occur suddenly (acute), whereas, in others, symptoms may develop over the course of a few months. If brucellosis is not treated, the disease may take months to resolve once appropriate therapy is begun. Brucellosis may be confined to a certain area of the body (local) or have serious widespread complications that affect various organ systems of the body including the central nervous system. Brucellosis may be prevented if people drink only pasteurized cow and goat’s milk. However, farmers and people exposed to butchered meat may also be affected by brucellosis. (For more information on this disorder, choose “brucellosis” as your search term in the Rare Disease Database).

Tularemia is found worldwide but this infectious disease is rare in the U.S. (approximately 120 cases are reported annually). It most often affects small mammals such as rabbits, rodents and hares. It is highly infectious and is most often transmitted to humans by handling an infected animal or being bit by an infected tick or fly. People have not been known to transmit the infection to others. The disease is caused by the bacterium Francisella tularensis. The severity of tularemia varies greatly. Some cases are mild and self-limiting others may have serious complications, and a small percentage (about 2 percent) can even become life-threatening. (For more information on this disorder, choose “tularemia” as your search term in the Rare Disease Database).


The signs and symptoms of Q fever are nonspecific and can be associated with a wide variety of diseases. A diagnosis of Q fever usually requires serological examination, which measures and characterizes antibodies. Q fever has two antibody-producing (antigenic) phases called phase I and phase II. These phases can help confirm a diagnosis and can help distinguish acute Q fever infection from chronic Q fever infection. Infected individuals develop specific antibodies against Q fever including immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM). Measuring the levels of these classes of antibodies can help confirm a diagnosis of Q fever. During the acute phase of Q fever, IgG and IgM antibodies may be detected. In chronic Q fever, IgG or IgA levels may be detected.

In acute Q fever, the levels of antibodies to phase II antigen of C. burnetii are higher than those to the phase I antigen and, in general, the formers are first detected during the second week of the illness.

In chronic Q fever, a high level of phase I antibodies with a constant or falling level of phase II antibodies together with other signs of inflammatory disease are common.

The three most common serological tests for Q fever are indirect immunofluorescence, complement fixation and enzyme-linked immunosorbent assay (ELISA). Indirect immunofluorescence is a test that enables physicians to detect the presence of specific antibodies in the blood or other fluids. The antibodies are tagged with a substance that causes them to glow when exposed to ultraviolet light. Complement fixation and ELISA tests can also detect the presence of specific antibodies or antigens.

Isolation of the infectious agent in cell cultures, embryonated hens eggs and laboratory animals is also possible, but required special laboratory with biosafety level three (BSL3).

A newer test that has been used to aid in the diagnosis of Q fever in some cases is a polymerase chain reaction (PCR) test. A PCR test is a highly sensitive test that amplifies a specific segment or sample of DNA, creating billions of copies that particular segment. This amplified segment can then be studied to detect the presence of C. burnetii infection. It has been employed successfully to detect C. burnetii DNA in cell cultures and biological samples.

The first nucleic acid amplification in vitro diagnostic (IVD) test by Idaho Technology, Inc. (ITI) was approved by the FDA in 2011 to detect Coxiella burnetii, the bacteria that causes Q fever. It will be used to test military personnel suspected of contracting the disease and run on the Joint Biological Agent Identification and Diagnostics System (JBAIDS), utilized across all branches of the military for diagnostic testing. Use of the test is limited to designated Department of Defense laboratories equipped with the JBAIDS.

Standard Therapies

Antibiotic therapy is used to treat individuals with Q fever. Some mild cases of Q fever may improve without treatment, although antibiotic therapy usually reduces the duration of the infection. Physicians recommend that all individuals in whom Q fever is detected receive antibiotic therapy, even those with no recognizable clinical findings (subclinical disease).

Doxycycline is currently the most commonly used antibiotic therapy for the treatment of individuals with Q fever and is most effective when started within three days of infection. Anti-inflammatory drugs may be used if individuals do not respond to antibiotics. Hydroxychloroquine, which is often used to treat malaria, has also been used to treat Q fever.

Chronic Q fever is more difficult to treat. Endocarditis may require prolonged antibiotic treatment which usually involves treatment with multiple drugs such as a combination of doxycycline and hydroxychloroquine whic. drastically reduces lethality. The optimal duration of therapy is unknown and may vary from one person to another.

In some individuals with damage to the heart valves or evidence of heart failure, surgery may be necessary. Decisions concerning the use of particular interventions such as surgery should be made by physicians (e.g., cardiologist, infectious disease specialist) and other members of the healthcare team in careful consultation with the patient, based upon the specifics of his or her case a thorough discussion of the potential benefits and risks patient preference and other appropriate factors.

There is no vaccine approved by the U.S. Food and Drug Administration (FDA) for Q fever. However, other countries have developed vaccines. In 1989, Australia licensed a vaccine against Q fever.

Investigational Therapies

Fluoroquinolones, which are antibiotics that kill bacteria or prevent their growth (antimicrobials), have also been used to treat individuals with Q fever. These drugs include ofloxacin, pefloxacin, and ciprofloxacin. Additional antibiotics that have been used to treat individuals with Q fever include chloramphenicol, co-trimoxazole and rifampin. More research is necessary to determine the long-term safety and effectiveness of these potential therapies.

Macrolides are a class of antibiotics that have been used to treat individuals with Q fever. A common macrolide is erythromycin. However, macrolides have generally been unreliable. Newer macrolides such as clarithromycin, azithromycin and roxithromycin have shown greater promise as potential therapies for Q fever. More research is necessary to determine the long-term safety and effectiveness of newer macrolides as potential treatments for individuals with Q fever.

The treatment of women who are pregnant has proven difficult because most standard therapies are unsafe for use during pregnancy. Pregnant women with Q fever are usually treated with a drug called co-trimoxazole until delivery because it lowers the risk of pregnancy complications. However, the drug is usually not curative and women may experience a new outbreak of infection following a disease-free or inactive period (recrudescence). After giving birth, a woman with Q fever infection can be treated as discussed above in standard therapies.

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    Kovacova E, Kazar J. Q Fever. In: NORD Guide to Rare Disorders. Lippincott Williams &Wilkins. Philadelphia, PA. 2003:293.

    Roest HJI, Tilburg JJHC, Van der Hoek W, Vellema P, et al. The Q fever epidemic in The Netherlands: history, onset, response and reflection. Epidemiol. Infect. 2011 139: 1-12.

    Kersh GJ, Wolfe TM, Fitzpatrick KA, et al. Presence of Coxiella burnetii DNA in the environment of the United States (2006-2008). Appl. Environ. Microbiol.201076 (13): 4469-4475.

    Omsland A, Cockrell DC, Howe D, et al. Host cell-free growth of the Q fever bacterium Coxiella burnetii. PNAS. 2009106(11): 4430-4434.

    Hartzell JD, Wood-Morris RN, Martinez LJ, Trotta RF. Q fever: epidemiology, diagnosis and treatment. Mayo Clin Proct. 2008 83:574-79.

    Parker NR, Barralet JH, Bell AM. Q fever.Lancet. 2006 367:679-88.

    Karakousis PC, Trucksis M, Dumler JS. Chronic Q fever in the United States.J Clin Microbiol. 200644:2283-87.

    Marrie TJ. Empiric treatment of ambulatory community-acquired pneumonia: always include treatment for atypical agents. Infect Dis Clin North Am. 200418:829-41.

    Marrie TJ. Q fever pneumonia. Curr Opin Infect Dis. 200417:137-42.

    Madariaga MG, Rezai K, Tenholme GM, et al. Q fever: a biological weapon in your backyard. Lancet Infect Dis. 20033:709-21.

    Kovacova E, Kazar J. Q fever – still a query and underestimated infectious disease. Acta Virol. 2002 46: 193-210.

    Maltezou HC, Raoult D. Q fever in children. Lancet Infect Dis. 2002 2:686-691.

    Migala AF, Neumann L. Q Fever. Emedicine Updated January 25, 2012. Accessed February 15, 2012.

    Mayo Clinic for Medical Education and Research. Q Fever. Updated August 2, 2011. Accessed February 15, 2012.

    Centers for Disease Control and Prevention. Q Fever. Update January 18, 2011. Accessed February 15, 2012.

    Years Published

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    Medical Definition of Fever

    Fever: Although a fever technically is any body temperature above the normal of 98.6 F (37 C), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 F (38 C).

    Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms. For that reason, low fevers should normally go untreated, although you may need to see your doctor to be sure if the fever is accompanied by any other troubling symptoms. As fevers range to 104 F and above, however, there can be unwanted consequences, particularly for children. These can include delirium and convulsions. A fever of this sort demands immediate home treatment and then medical attention. Home treatment possibilities include the use of aspirin or, in children, non-aspirin pain-killers such as acetaminophen, cool baths, or sponging to reduce the fever while seeking medical help. Fever may occur with almost any type of infection of illness. The temperature is measured with a thermometer.

    Can You Prevent It?

    The best way to steer clear of TBRF is to avoid getting a tick bite. If you’re in a place where there are ticks, wear bug repellent when you go outside. You can use permethrin on your clothes or a DEET product on your skin and clothes. If you’re staying in a cabin, check for signs of rodents, like their droppings. A pest control professional can remove them and their nests.


    CDC: “Be Aware of Tick-Borne Relapsing Fever,” “Tick-Borne Relapsing Fever.”

    Morbidity and Mortality Weekly Report (MMWR): “Tickborne Relapsing Fever -- United States, 1990-2011.”

    University of California UC Davis Department of Entomology and Nematology: “Tick Biology.”

    American Lyme Disease Foundation: “Tick-borne Relapsing Fever.”

    Infectious Disease Clinics of North America: “Tick-Borne Relapsing Fever.”