Disease Causative Agents

Typhoid is caused by Salmonella typhi, pneumonia by Streptococcus pneumoniae, and tuberculosis by Mycobacterium tuberculosis. All three are bacterial infections.

H5N1 is the highly pathogenic avian influenza virus that causes bird flu in birds and can occasionally infect humans.

Diarrhoea is a condition characterized by frequent loose or liquid bowel movements, which is a disorder of the gastrointestinal tract.

Japanese encephalitis is a viral infection that causes inflammation of the brain, often referred to as brain fever. The other options represent entirely different categories of diseases.

Hepatitis is an inflammatory condition of the liver, typically caused by viral infections. Kalaazar affects the spleen and bone marrow, while SARS and amoebiasis target the lungs and intestines respectively.

Common cold viruses are highly contagious and can be transmitted through respiratory droplets in the air, contaminated surfaces, or direct contact with infected individuals.

Rabies is a zoonotic disease transmitted primarily through the saliva of infected animals, most commonly via a bite. It is not spread through casual physical contact or sexual activity.

The immune system is the body's defense mechanism designed to identify and neutralize foreign invaders like bacteria and viruses. Other systems perform structural or metabolic functions.

SARS (Severe Acute Respiratory Syndrome) is caused by a coronavirus, which is a type of virus. It is not caused by bacteria, fungi, or protozoa.

Tuberculosis is primarily a respiratory disease caused by Mycobacterium tuberculosis, which typically infects the lungs after being inhaled.

Hepatitis A is primarily transmitted through the fecal-oral route, often via contaminated water or food. It is not typically spread by air or physical contact.

Diarrhoea is a condition defined by frequent loose or liquid bowel movements, which often leads to significant fluid loss and dehydration. It is a common symptom of various gastrointestinal infections.

Hepatitis is an inflammatory condition of the liver, and it is commonly caused by viral infections (Hepatitis A, B, C, etc.). Jaundice is a clinical sign of hepatitis, as the liver fails to process bilirubin properly.

Brain fever, or encephalitis, is most commonly caused by viral infections, such as Japanese encephalitis or herpes simplex virus. While bacteria can cause meningitis, the term brain fever is frequently associated with viral causes in general contexts.

 Caused by an invasion and by organisms from outside.