Olympiad Test: Why do We Fall Ill- 3 - Class 9 MCQ

The diseases which are transmitted through contaminated air are known as airborne diseases. When the person lives in an overcrowded area which is poorly ventilated house, the person may suffer from breathing and airborne related diseases. The person may suffer from respiratory infections and disorders.

Human immunodeficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS). HIV is transmitted primarily via unprotected sexual intercourse, contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding. Whereas elephantiasis is caused by the filarial worms or helminths, polio is caused by poliovirus and malaria is a protozoan infection caused by Plasmodium.

Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus, called SARS-associated coronavirus (SARS-CoV). Swine flu is caused by a virus. The most common subtype, or strain is the influenza type A H₁N₁ virus.

Mosquitoes can transmit diverse infectious pathogens and parasites that cause diseases such as dengue, Zika, Chikungunya, West Nile fever, or malaria. Therefore, mosquitoes are so-called disease vectors. In order to do so, though, a mosquito must bite a sick human first, thereby infecting itself with the pathogen. After some time (usually around ten days), the mosquito itself becomes infectious.

Poliomyelitis and Hepatitis are viral diseases, Malaria is a protozoan disease. Tetanus is a bacterial disease caused by Clostridium tetani. It is a soil borne disease and gains entry into the body through open wounds.

So, the correct answer is 'Tetanus'

Tobacco smoking can lead to lung cancer, chronic bronchitis, and emphysema.It increases the risk of heart disease, which can lead to stroke or heart attack. It can cause an increase in blood pressure, heart rate, flow of blood to the heart and a narrowing of the arteries (vessels that carry blood). The chemicals in tobacco smoke damage the delicate lining of the lungs and can cause permanent damage that reduces the ability of the lungs to exchange air efficiently.

Tuberculosis is an infectious disease usually caused by Mycobacterium tuberculosis bacteria. Tuberculosis generally affects the lungs, but can also affect other parts of the body. The symptoms of active TB is a chronic cough with blood-containing sputum, fever, night sweats, and weight loss. First line treatment for TB is streptomycin, ethambutol, isoniazid, rifampicin and pyrazinamide. So, the correct answer is 'Streptomycin'.

When HIV attacks the host organism they infect the cells of the immune system and destroys the T-helper lymphocytes or T-cells, which are crucial to the immune system and generation of the immune response. The HIV in the body is able to copy itself over and over through the reverse transcription mechanism, increasing its ability to kill CD4+ or helper T-cells and this is the first step in the occurrence of AIDS and development of the symptoms.

Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. Ascariasis does not spread directly from person to person. Infection occurs by eating food or drink contaminated with Ascaris eggs from feces. The eggs hatch in the intestines, burrow through the gut wall, and migrate to the lungs via the blood. There they break into the alveoli and pass up the trachea, where they are coughed up and swallowed. The larvae then pass through the stomach for a second time into the intestine where they become adult worms.

An allergy is a non-communicable disease and is a medical condition that makes a person feel unwell when they eat or come in contact with a particular substance like itchy ears and eyes, eating of food like milk and egg.

It occurs when the body’s immune system overreacts to a normally harmless substance/condition.

Malaria, diarrhea, and tuberculosis are diseases that are caused by pathogens. Thus, these diseases are communicable and can easily transfer from an infected person to a healthy person.