Typhoid fever is an infectious disease caused by a baterium called
Salmonella typhi. The source of this infectious agent are
human carriers i.e. persons who excrete the bacteria through their
faeces without having any symptoms. However, for them the typhoid
bacteria still live inside their gall-bladders abd are excreted
a little bit at a time through their faeces. People get typhoid
fever if they consume food or water indirectly contaminated with
typhoid bacteria from carriers.
The incubation period of typhoid is about 10 - 14 days . During
this period , the typhoid bacteria multiply inside the host cells.
They are then released into the blood stream resulting in bacteremia
and siddemination to various organs of the body. Clinical presentations
vary tremendously among patients and range from mild such as headache,
diarrhoe , low grade fever and malaise to severe symptoms including
splenomegaly, hepatomegaly, delirium and shock.since symptoms seen
with typhoid are similar to other diseases with fever common areas
endemic for typhoid, a definitive clinical diagnosis is difficult,hence
the need for a good laboratory test.
Typhoid fever is endemic in the asia pacific region, the Indian
subcontinents, Central Asia, Africa and South America. There are
no accurate figures on the incidence of typhoid fever. However,
WHO has estimated that there are 16.6 million cases of tyhoid annually
with about 600,000 deaths.