Vaccines – Typhoid and Paratyphoid Fever

May/June 2012 ISSN-1059-6518 Volume 25 Number 3

By Frank Hubbell, DO


What is Typhoid and Paratyphoid?

Typhoid fever, also known as typhoid is a life-threatening illness caused by the bacterium Salmonella typhi. It is also known as gastric fever, abdominal typhus, infantile remittant fever, slow fever, nervous fever, and pythogenic fever.

Paratyphoid fever, also known as enteric fever, is a less serious illness that is also caused by Salmonella bacteria, but the symptoms are very similar to those of Typhoid Fever.


Warning: Typhoid fever is different from Typhus. Typhus is an illness caused by the bacterium Rickettsia while Typhoid is caused by Salmonella bacteria.


Pathophysiology of Typhoid:

Salmonella typhi lives only in humans – there is no other reservoir in nature besides humans.

The Salmonella typhi is spread from one person to another via the oral-fecal route where food or water has become contaminated by poor sanitation. Inadequate conditions have allowed the water source to become contaminated with human excrement – urine and feces, or by improper food handling and preparation.

Salmonella can also be spread by flying insects, such as flies, that feed on feces and then land and walk on food that you might then eat.

Flies: Their dirty little foot prints on your food is enough to spread Salmonella and other intestinal illnesses from one animal to another.

Once the Salomella bacterium has been consumed in food or water, it passes through the stomach into the intestinal tract where is multiplies and invades the mucosa wall. Within the mucosa wall the Salmonella bacteria are phagocystized (surrounded and consumed) by macrophages (white blood cells). If the bacteria manage to avoid the immune system in the gut wall, they will then invade and multiple in the blood stream.

It is the invasion and multiplication of the Salmonella in the bloodstream that causes the signs and symptoms of Typhoid.

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