Paratyphoid fever
This about the disease paratyphoid fever. See typhus
Epidemic typhus is a form of typhus so named because the disease often causes epidemics following wars and natural disasters...

 for an unrelated disease with a similar name. Typhoid fever
Typhoid fever
Typhoid fever, also known as Typhoid, is a common worldwide bacterial disease, transmitted by the ingestion of food or water contaminated with the feces of an infected person, which contain the bacterium Salmonella enterica, serovar Typhi...

 is a related disease but is caused by a different bacterium.

Paratyphoid fevers or Enteric fevers are a group of enteric illnesses caused by serotypic strains of the Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, S. Paratyphi.

NOTE: The concept of "serovars" is important to the nomenclature regiment for the Salmonella genus. Serovar names also follow the genus, but are not to be confused with species. Unlike species names, serovars are always capitalized and never italicized/underlined.

There are three serovars of the species of S. enterica that cause paratyphoid: S. Paratyphi A, S. Paratyphi B (S. schottmuelleri and S. pullorum), and S. Paratyphi C (S. hirschfeldii).

They are transmitted by means of contaminated water or food.

The paratyphoid bears similarities with typhoid fever, but its course is more benign.


Factors outside the household like unclean food from street vendors and flooding help distribute the disease from person to person.
Because of poverty and poor hygiene and sanitary conditions the disease is more common in less-industrialized countries, principally owing to the problem of unsafe drinking-water, inadequate sewage disposal and flooding. Occasionally causing epidemics, paratyphoid fever is found in large parts of Asia, Africa, Central and South America. Many of those infected get the disease in Asian countries. There are about 16 million cases a year, which result in about 25,000 deaths worldwide. Salmonella Typhi can specifically only attack humans, so the infection nearly always comes from contact another human, either an ill person or a healthy carrier
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...

 of the bacterium. The bacterium is passed on with water and foods and can withstand both drying and refrigeration but by keeping food refrigerated correctly this minimizes the production of the bacterium significantly.Bla Bla Bla


Paratyphoid fever is caused by any of three strains of Salmonella paratyphoid: S. paratyphoid A; S. schottmuelleri (also called S. paratyphoid B); or S. hirschfeldii (also called S. paratyphoid C). It starts when the bacterium Salmonella typhi is passed from another person due to bad hygiene such as not washing your hands after using the restroom. Eventually the bacterium passes down to the bowel, then penetrates the intestinal mucosa (lining) to the underlying tissue. If the immune system is unable to stop the infection here, the bacterium will multiply and then spread to the bloodstream, after which the first signs of disease are observed in the form of fever. The bacterium penetrates further to the bone marrow, liver and bile ducts, from which bacteria are excreted into the bowel contents. In the second phase of the disease, the bacterium penetrates the immune tissue of the small intestine, and the initial symptoms of small-bowel movements begin.


Paratyphoid fever resembles Typhoid Fever but presents with a more abrupt onset, milder symptoms and a shorter course. Infection is characterized by a sustained fever, headache, abdominal pain, malaise, anorexia, a non productive cough (in early stage of illness), a relative Bradycardia (slow heart rate), and Hepatosplenomegaly (an enlargement of the liver or spleen). Approximately 30% of Caucasians will develop rosy spots on the central body. In adults, constipation is more common than diarrhea. Only 20% to 40% of people will initially have abdominal pain. Nonspecific symptoms such as chills, diaphoresis (perspiration), headache, anorexia, cough, weakness, sore throat, dizziness, and muscle pains are frequently present before the onset of fever. Some very rare symptoms are psychosis (mental disorder), confusion and seizures.


Those diagnosed with Type A of the bacteria strain rarely die from it save in rare cases of severe intestinal complications. With proper testing and diagnosis, the mortality rate falls to less than 1%. Antibiotics such as Azithromycin
Azithromycin is an azalide, a subclass of macrolide antibiotics. Azithromycin is one of the world's best-selling antibiotics...

 are particularly effective in treating the bacteria.


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 Schistosoma (parasitic blood fluke). It is possible to continue to shed Salmonella Paratyphi for up to one year and, during this phase, a person is considered to be a carrier. The chronic carrier state may follow acute illness, mild or even sub clinical infections. Chronic carriers are most often women who were infected in their middle age.


Children and adults should be carefully educated about personal hygiene. This would include careful hand washing after defecation and sexual contact, before preparing or eating food, and especially the sanitary disposal of feces. Food handlers should be educated in personal hygiene prior to handling food or utensils and equipment. Infected individuals should be advised to avoid food preparation.

Those who travel to countries with poor sanitation should receive a Typhoid vaccine
Typhoid vaccine
Typhoid vaccine is a vaccine used against typhoid fever.There are two effective types:* Ty21a, which is a live vaccine* Vi capsular polysaccharide vaccine, which is a subunit vaccine...

, which provides protection against Paratyphoid Infection B, prior to departure. Sexually active people should be educated about the risks of sexual practices that permit fecal-oral contact.
Owners of tropical fish should ensure scrupulous cleaning of aquariums to eliminate potential S. Paratyphi B organisms.


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. Control requires treatment of antibiotics and vaccines prescribed by a doctor. Major control treatments for Paratyphoid fever include Ciprofloxacin for ten days or Ceftriaone/Cefotaxime for 14 days or Aziththromycin.

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
Herpes labialis
Herpes labialis or "orolabial herpes" is an infection of the lip by herpes simplex virus . An outbreak typically causes small blisters or sores on or around the mouth commonly known as cold sores or fever blisters...

, rare in true typhoid fever, is frequently seen in Para B.

Diagnosis is with isolation of the agent in blood or stool and demonstration of antibodies anti BH in the Widal test.

The disease responds well to chloramphenicol
Chloramphenicol is a bacteriostatic antimicrobial that became available in 1949. It is considered a prototypical broad-spectrum antibiotic, alongside the tetracyclines, and as it is both cheap and easy to manufacture it is frequently found as a drug of choice in the third world.Chloramphenicol is...

 or co-trimoxazole
Trimethoprim/sulfamethoxazole or co-trimoxazole is a sulfonamide antibiotic combination of trimethoprim and sulfamethoxazole, in the ratio of 1 to 5, used in the treatment of a variety of bacterial infections.The name co-trimoxazole is the British Approved Name, and has been marketed worldwide...


Paratyphoid C

Paratyphoid C is a rare infection, generally seen in the Far East. It presents as a septicaemia with metastatic
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...

An abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...

es. Cholecystitis
-Signs and symptoms:Cholecystitis usually presents as a pain in the right upper quadrant. This is known as biliary colic. This is initially intermittent, but later usually presents as a constant, severe pain. During the initial stages, the pain may be felt in an area totally separate from the site...

 is possible in the course of the disease.

An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

to para C are not usually tested and the diagnosis is made with blood cultures.

Chloramphenicol therapy is generally effective.

Further Reading

  • Harman, Robin J. “Paratyphoid fever.” Handbook of Pharmacy Healthcare. Pharmaceutical Press: 2002
  • Sweet, William Merrick. “Paratyphoid Infections.” American Journal of Medical Sciences. Lea Brothers & Co: 1902
  • “Typhoid and Paratyphoid Fever.” Communicable Disease Management Protocol. November 2001
  • “Typhoid and Paratyphoid Fever.” Public Health Notifiable Disease Management Guidelines. Disease Control and Prevention. Alberta Health and Wellness: December 2005
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