Paratyphoid Fever caused by Salmonella enterica serovars Paratyphi

Enteric fever (typhoid and paratyphoid fever) is caused by Salmonella enterica serovars Typhi (S. Typhi) and Salmonella enterica serovars Paratyphi (S. Paratyphi). S. Paratyphi A and B (and, uncommonly, S. Paratyphi C) cause a disease that is clinically indistinguishable from typhoid fever, particularly in parts of Asia.

Generally, S. Paratyphi A is a Gram-negative bacterium that belongs to the Enterobacteriaceae family. Paratyphoid Fever is the same as for typhoid fever but disease is usually milder. S. Paratyphi A can be isolated from the blood and faeces from paratyphoid fever patients. This bacterium causes a milder infection with lower mortality and chronic carriage rate compared to S.Typhi.

Paratyphoid fever is transmitted by ingestion of food or water contaminated with feces or urine of infected people or directly from person to person. Shellfish harvested from sewage-contaminated water are potential vehicles, as are fruits and vegetables grown in soil fertilized with human waste. Family contact could be a factor of transmission as well, but a recent report on the risk factors for the disease showed that paratyphoid infections occur mostly outside the household.

The symptoms of typhoid and paratyphoid fever are similar although paratyphoid tends to be less severe than typhoid. Symptoms of S. Paratyphi A infection include fever, headache, diarrhoea or constipation, malaise, anorexia, nausea, dry cough, gastrointestinal symp-toms, abdominal pain, chills, raised spots or rashes on body.

Typhoid can be prevented by being vaccinated before travelling to a developing country. Additionally, people travelling in developing countries should:
*avoid uncooked foods, including fruit unless it is able to be peeled
*avoid untreated water, including ice
*drink from sealed containers (i.e. bottles or cans)
*wash their hands after going to the toilet and before eating
*avoid eating from street stalls
*ensure hot food is thoroughly cooked and eaten while hot.
Paratyphoid Fever caused by Salmonella enterica serovars Paratyphi

Typhoid Fever

Typhoid Fever
Typhoid fever is caused by the gram positive bacillus Salmonella typhi. Paratyphoid fevers, which are usually milder but may be clinically indistinguishable, are caused by Salmonella paratyphi A, Salmonella schotiilleri, or Salmonella hirschfeldii (formerly Salmonella paratyphi A, B, C). Children usually have a shorter incubation period than do adults (usually 5 – 8 days instead of 8 – 14 days).

The organisms enter the body through the walls of the intestinal tract and, following a transient bacteremia, multiple in the reticuloendothelial cells of the liver and spleen. Persistent bacteremia and symptoms then follow. Reinfection of the intestine occurs as organisms are excreted in the bile, bacterial emboli produce the characteristic skin lesions. Symptoms in children may be mild or severe, but children under age 5 years really have severe typhoid fever.

Typhoid fever is transmitted by the fecal oral route and by contamination of food or water. Unlike Salmonella species, there are no animal reservoirs of S typhi; each case is the result of direct or indirect contact with the organism or with an individual who is actively infected or a chronic carrier.

About 500 cases per year are reported in the United States, 60% of which are required during foreign travel.
Typhoid Fever