Paratyphoid Fever

Reporting Obligations

Individuals with suspect or confirmed cases must be reported to the Thunder Bay District Health Unit by the next working day by fax, phone or mail.

  • Fax: (807) 625-4822
  • Phone: 625-5930 or toll-free at 1-888-294-6630, ext. 5930
  • Mail: 999 Balmoral Street, Thunder Bay, ON P7B 6E7



Aetiologic Agent:

Paratyphoid fever is caused by Salmonella enterica subspecies enterica serotype Paratyphi A, B and C (commonly S. Paratyphi).

Note that Salmonella Paratyphi B variant Java should be reported as a case of salmonellosis, not paratyphoid fever.

Clinical Presentation:

Paratyphoid fever is a systemic bacterial disease which usually presents with fever, headache, malaise, anorexia, and diminished frequency of stool which is more common than diarrhea, plus bradycardia, enlargement of spleen and rose spots on trunk in 25% of white-skinned patients.

The clinical picture varies from mild illness with low-grade fever to severe clinical disease with abdominal discomfort and multiple complications. Peyer patches in the ileum can ulcerate with intestinal hemorrhage or perforation, especially late in untreated cases.

Modes of transmission:

Fecal-oral route. Transmitted via ingestion of food and water contaminated by feces and urine of cases and carriers; also by ingestion of contaminated milk, raw fruit and vegetables and shellfish harvested from contaminated water. Flies may be vectors. Person-to-person transmission has also been documented.

Incubation Period:

1-10 days

Period of Communicability:

Communicable as long as organisms are excreted; from the appearance of prodromal symptoms, throughout illness and for periods of up to two weeks after onset.


Risk Factors/Susceptibility

Susceptibility is general and is increased in individuals with gastric achloryhdria and possibly in those who are HIV positive. Relative specific immunity follows recovery from clinical disease and inapparent infection.

Travellers should be referred to travel clinics to assess their personal risk and appropriate preventive measures.


Diagnosis & Laboratory Testing

Laboratory confirmation of infection with or without clinically compatible signs and symptoms (characterized by insidious onset of sustained fever, headache, malaise, anorexia, relative bradycardia, constipation or diarrhea):

• Isolation of Salmonella Paratyphi A, B, or C (excluding S. Paratyphi B variant Java) from an appropriate clinical specimen (e.g., sterile site, blood, stool, urine).

Testing Information & Requisition


Treatment & Case Management

Treatment with antibiotics and follow up is under the direction of the attending health care provider. Where possible, physicians should be encouraged to request antibiotic sensitivity testing due to resistant strains. With appropriate antibiotic treatment, infected individuals with typhoid or paratyphoid fever usually recover within ten to 14 days. Educate the case about transmission of infection and proper hand hygiene.

Exclude all cases (regardless of symptoms) of S. Paratyphi from food handling, healthcare and daycare activities until provision of 3 consecutive negative stool samples collected at least 48 hours apart AND at least 48 hours after completion of antibiotic treatment (for cipro oxacin) OR at least 2 weeks after completion of antibiotic treatment (for ceftriaxone and azithromycin). Close contacts should be seen by their health care provider and screened for illness (stool specimens sent for testing).

If after 6 samples, a case continues to test positive, then he or she may be in an excreter state.


Patient Information

Patient Fact Sheet


1. Ministry of Health and Long Term Care, Infectious Diseases Protocol - Appendix 1 (2022) Paratyphoid Fever.

2. Public Health Ontario. "Paratyphoid Fever".


Additional Resources

1. Centers for Disease Control and Prevention. "Typhoid and Paratyphoid Fever."

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