Disease Causative Agents

Shiga toxin causes fluid accumulation in the intestine, kills various cells by inactivating the 60S subunit of eukaryotic ribosomes and damages the walls of blood vessels.

Haemophilus influenzae causes epiglottitis in older children. In this disease, epiglottis is inflamed. It gets swollen to the extent that blockage of the trachea occurs and breathing is obstructed.

Yersinia pseudotuberculosis causes gastroenteritis.

Rickettsia prowazekii causes typhus fever. Its symptoms are chills, fever, headache, generalised aches, pains and exhaustion.

Pseudomonas aeruginosa produces a potent exotoxin (in addition to an endotoxin) to manifest its infection. The lethal exotoxin produced is called toxin A. It has a mechanism of action identical to that of diphtheria toxin.

Legionnaires' disease is a severe bronchopneumonia. It is characterised by fever, chills and non-productive dry cough. The symptoms sometimes include chest pain, abdominal pain, vomiting, diarrhoea and mental confusion.

Brucella suis occurs in swine and is transmitted to humans during the processing of meat of the infected swine.

Campylobacter jejuni is most often associated with gastroenteritis. This species produces exudative and hemorrhagic inflammation of the intestinal walls and leads to several cases of diarrhoea.

Heat labile toxin (HLT) causes damage to epithelium of the respiratory tract.

Botulinum (food poison) is caused by Clostridium botulinum. Syphilis is caused by Treponema pallidum.

Ranikhet disease, also called Newcastle disease, is a viral disease that specifically affects poultry (birds like chickens and ducks). The disease causes respiratory and neurological symptoms in birds and does not affect mammals like buffaloes, goats, or pigs.

Ehrlichiosis is an emerging bacterial disease in which obligate intracellular bacteria infect and kill white blood cells. It is caused by Anaplasma phagocytophilum, Ehrlichia ewingii, Ehrlichia chaffeensis or Neorickettsia sennetsu.

Enterovirus 71 causes polio-like syndrome or permanent paralysis. This virus appears to have evolved only recently with the first known strain isolated in 1965.

Typhoid Mary was a chronic carrier and was presumed to have infected 51 people, three of whom died. She harboured the pathogen inside her body for a long time.

The causative organism for 1918-1919 pandemic was influenza virus. It took 20 million lives.