Clinical Overview of Typhoid Fever and Paratyphoid Fever


  • This page provides a brief overview of typhoid fever and paratyphoid fever characteristics, including transmission and risk factors.
  • It also highlights current trends in antimicrobial resistance.
  • Information on identifying, diagnosing, and treating these diseases is available on the Clinical Guidance page.
An illustration of a group of Salmonella typhi bacteria floating in liquid. They are rod-shaped with little strands, or flagella, coming off each of them.



Salmonella Typhi and Salmonella Paratyphi are transmitted commonly through the consumption of drinking water or food contaminated by feces from an ill person or carrier.

Risk factors

Risk for infection is greatest among people who

  • Travel to countries in Africa, Asia, or Latin America where the diseases are common
  • Visit rural areas of those countries
  • Visit family and friends in those countries
  • Are not vaccinated against typhoid fever

Most people in the United States with typhoid fever (85%) and paratyphoid fever (80%) report international travel in the 30 days before their illness. Most (70%) of these people traveled to South Asia (e.g., India, Bangladesh, Pakistan).


The incubation period for typhoid fever is typically 6 to 30 days, and 1 to 10 days for paratyphoid fever.


Extensively drug-resistant (XDR) typhoid fever

  • An outbreak of XDR typhoid fever began in Pakistan in 2016. Cases of XDR typhoid fever, including among people in the United States, continue to occur. See CDC's Travel Health Notice >
  • Cases of XDR typhoid fever also have been reported in the United States among people without recent international travel. See CDC's health advisory >