Transmission
They are usually spread by eating or drinking food or water contaminated with the feces of an infected person. They may occur when a person who prepares food is infected. Risk factors include poor sanitation as is found among poor crowded populations. Occasionally, they may be transmitted by sex. Humans are the only animals infected. Paratyphoid B
Paratyphoid B is more frequent in Europe. It can present as a typhoid-like illness, as a severe gastroenteritis or with features of both. Herpes labialis, rare in true typhoid fever, is frequently seen in paratyphoid B. Rarely a subdural empyema can occur. Diagnosis is with isolation of the agent in blood or stool and demonstration of antibodies antiBH in the Widal test. The disease responds well to chloramphenicol or co-trimoxazole. Paratyphoid C
Paratyphoid C is a rare infection, generally seen in the Far East. It presents as a septicaemia with metastatic abscesses. Cholecystitis is possible in the course of the disease. Antibodies to paratyphoid C are not usually tested and the diagnosis is made with blood cultures. Chloramphenicol therapy is generally effective. Carriers
Humans and, occasionally, domestic animals are the carriers of paratyphoid fever. Members of the same family can be transient or permanent carriers. In most parts of the world, short-term fecal carriers are more common than urinary carriers. The chronic urinary carrier state occurs in those who have schistosomiasis (parasitic blood fluke).Continuing to shed Salmonella Paratyphi is possible for up to one year, and during this phase, a person is considered to be a carrier.
Sexually active people should be educated about the risks of sexual practices that permit fecal-oral contact.Those who travel to countries with poor sanitation should receive a live attenuated typhoid vaccine—Ty21a (Vivotif), which, in addition to the protection against typhoid fever,  may provide some protection against paratyphoid fever caused by the S. enterica serotypes A and B. In particular, a reanalysis of data from a trial conducted in Chile showed the Ty21a vaccine was 49% effective (95% CI: 8–73%) in preventing paratyphoid fever caused by the serotype B. Evidence from a study of international travelers in Israel also indicates the vaccine may prevent a fraction of infections by the serotype A, although no trial confirms this. This cross-protection by a typhoid vaccine is most likely due to O antigens shared between different S. enterica serotypes.Exclusion from work and social activities should be considered for symptomatic, and asymptomatic people who are food handlers, healthcare/daycare staff who are involved in patient care and/or child care, children attending unsanitary daycare centers, and older children who are unable to implement good standards of personal hygiene. The exclusion applies until two consecutive stool specimens are taken from the infected patient and are reported negative. Treatments
Control requires treatment of antibiotics and vaccines prescribed by a doctor. Major control treatments for paratyphoid fever include ciprofloxacin for 10 days, ceftriaxone/cefotaxime for 14 days, or aziththromycin. Prognosis
Those diagnosed with Type A of the bacterial strain rarely die from it except in rare cases of severe intestinal complications.