Disease Causative Agents

The causative agent of mad-cow disease is a prion. Bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, is a fatal neurodegenerative disease or encephalopathy in cattle that causes a spongy degeneration in the brain and spinal cord. It is caused due to a prion. A prion is an infectious agent, specifically a protein in a misfolded form. The protein itself, whether in its misfolded or its correctly folded form, can be referred to as the prion protein (PrP). A protein as an infectious agent stands in contrast to all other known infectious agents, like viruses, bacteria, fungi, or parasitesall of which must contain nucleic acids.

AIDS is caused by HIV virus and transmits sexually.
Jacob syndrome is characterized by an extra copy of Y chromosome in a male. Thalassemia is an inherited autosomal recessive blood disorder characterized by abnormal formation of hemoglobin. Whereas asthma is a respiratory condition caused by attacks of spasm in the bronchi of the lungs, causing difficulty in breathing. One of its cause is coming in contact with some air-borne allergens or exposure to some viral infections in infancy or in early childhood when the immune system is developing.
Thus, the correct answer is option B.

Antibiotics are used against bacterial diseases and malaria is a protozoan disease.

Common cold spreads through the mucus of the infected people during sneezing and coughing.

A non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another. Communicable diseases are infectious.

Communicable diseases are the disease that can spread from one person t another by any means of body or blood contact common cold can spread by sneezing in public without covering mouth and chicken pox spreads in the same manner as the cold by sneezing it can also spread through the fluid from the blisters.

An allergy is a non-communicable disease and is a medical condition that makes a person feels 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.

Communicable diseases spread from one person to another or from an animal to a person. The spread often happens via airborne viruses or bacteria, but also through blood or other bodily fluid. The terms infectious and contagious are also used to describe communicable disease.

Leprosy is an infectious disease. It affects the peripheral nerves, skin, upper respiratory tract, eyes, and nasal mucosa. It is caused by a bacillus bacterium known as Mycobacterium leprae. It can be considered as a mild infection because it can be easily cured by the drugs like dapsone. 

Deficiency diseases are the diseases that are caused due to deficiency of vitamin or minerals in the food and is not a communicable disease as it cannot be transferred for person to person by touch or any fluid as it is not caused by any bacteria or virus.

Droplet infection is the infection which is transmitted by the oral discharge during coughing and sneezing. It is a direct method of infection where the pathogens are easily transmitted from the carrier to the healthy host.

Asthma is a respiratory condition marked by attacks of spasm in the bronchi of the lungs, causing difficulty in breathing. It is usually connected to the allergic reaction or other forms of hypersensitivity. Hay fever is the common name for allergic rhinitis. It is an allergic reaction to allergens, or triggers, breathed in through the nose. When one of these allergens is breathed in, there is an immune response in the lining of the nose. This causes the nasal passages to become swollen and inflamed. Asthma and hayfever are closely linked, and approximately 80% of people with asthma also suffer from hayfever.

Tuberculosis (TB) is an acute or chronic infection caused by the tubercle bacillus Mycobacterium tuberculosis. Viral fever is an acute viral infection. The most common viral fever is the seasonal flu. The virus is spread when an infected person coughs or sneezes. The common cold is a viral infectious disease of the upper respiratory tract which primarily affects the nose. It usually resolves in seven to ten days, with some symptoms lasting up to three weeks. Examples of chronic illnesses are cancer, AIDS, kidney disease and diabetes.

Parkinson is a disease which can stay for a lifetime. Hence, it is a chronic disease. Therefore, (b) is the correct answer.

Infectious diseases are disorders caused by microorganisms such as bacteria, viruses, fungi or parasites. Therefore, (c) is the correct answer.