Typhoid and Paratyphoid Fevers (THE ENTERIC FEVERS)
In many countries where sanitation is primitive, enteric fevers, which are transmitted by the faecal-oral route, are an important cause of illness. Elsewhere they are relatively rare. Nevertheless, outbreaks occur from time to time and the infection may be contracted by persons travelling abroad.
Aetiology. The enteric fevers are caused by infection with Salmonella typhi and paratyphi which are specific human pathogens. Other members of the Salmonella group, many of which cause infection and disease in animals, produce disease in man ranging from mild food poisoning to more serious infection which may simulate many of the features of paratyphoid fever including bateraemia. Typhoidand paratyphoid infections have a world-wide distribution and occur endemically wherever sanitation is poor and the water supply is laible to be contaminated by human excreta. In such region flies may also transmit the disease. In Britain spread is usually by carriers, often food handlers, through the contamination of food, milk or water; infected shell fish are occasionally responsible for an outbreak. The bacilli may live in the gallbladder for months or years after clinical recovery and pass intermittently in the stools. S. typhi and S. paratyphi B are the organisms encountered in Britain.