Typhoid and paratyphoid are bacterial infections of the intestinal tract and bloodstream. The bacterium responsible for typhoid is called Salmonella typhi and the bacterium responsible for paratyphoid is Salmonella paratyphi.
Transmission is faecal-oral, this is food and/or water becomes infected through direct faecal contamination or by germs carried on inadequately washed hands. Flies can also play an important part in transmission and shellfish feeding at sewage outlets can become contaminated.
The illness becomes evident within one to two weeks after infection. It is characterised by fever, headache, loss of appetite and muscle pains sometimes accompanied by a dry cough. the fever is initially low-grade but increases as the disease progresses. Diarrhoea occurs often though not in all cases. Untreated, life-threatening complications may occur such as intestinal perforation or septicaemia with heart and brain involvement.
Typhoid may occur anywhere in the world, but are more common in places with unsafe water supplies and poor sanitation, such as:
- India, Pakistan and Bangladesh
- South-East Asia
- Several countries of the South Pacific, including Papua New Guinea
- Central and South America
- the Caribbean
- African countries
- countries of the Middle East.