Typhoid fever
Introduction
Typhoid fever is a bacterial infection caused by Salmonella Typhi (Salmonella enterica subsp. enterica serovars Typhi), characterized by fever and potentially severe complications. Paratyphoid fever is an infection with the closely related bacteria Salmonella Paratyphi (Salmonella enterica subsp. enterica serovars Paratyphi), clinically the course is similar although rather milder.
Together they are referred to as enteric fever, with Salmonella Typhi responsible for approximately 80% of cases.
Transmission
It is primarily transmitted via the fecal-oral route, through ingestion of food or water contaminated with faeces from infected individuals. The bacteria can survive for a varying number of weeks in water, ice, dust and can multiply in food. Both acutely ill as aymptomatic persons can excrete the bacteria. Chronic asymptomatic carriers may show no symptoms but can continue to shed the bacteria for months or even years after recovery. Humans are the only known reservoir for these pathogens. Sexually transmitted infections have also been described.
Incubation period
The incubation period can range from 6 to 30 days.
Symptoms
Typhoid fever and paratyphoid fever have similar clinical presentations, which can vary from mild illness to severe and potentially life-threatening disease. However, paratyphoid fever generally has a lower case-fatality rate compared to typhoid fever.
Symptoms usually begin with a gradually rising fever, accompanied by general signs such as malaise, headache, and loss of appetite. Patients often experience abdominal pain, diarrhoea and constipation. Other possible symptoms include a dry cough, a maculopapular rash, and hepatosplenomegaly.
If left untreated, it can lead to life-threatening complications like gastrointestinal haemorrhage, intestinal perforation, and encephalopathy.
The case fatality rate is approximately 10% for untreated cases in low-income settings and <1% for patients receiving care in high income countries.
Risk for traveller
For most travellers, the risk of enteric fever is low.
The risk is higher for travellers who travel for a longer period of time to the Indian subcontinent or who travel to their country of origin to visit family and friends, especially if they stay in poor hygienic conditions.
Risk areas
Typhoid and paratyphoid fever are endemic in tropical and subtropical regions, especially in regions were water and food are unsafe, and sanitation is poor. The incidence is the highest on the Indian sub-continent (India, Pakistan, Bangladesh and Nepal). There is also increasing antibiotic resistance in this region. The disease also occurs in other areas in Asia and Africa. The risk in Latin America is low.
Among travellers, most cases occur in individuals returning from the Indian subcontinent.
Prevention
Travellers should be advised on:
- Food and water precautions, which are also recommended to prevent traveller’s diarrhoea.
- For some travellers: typhoid vaccination (Salmonella Typhi).
Additional information
- Wikitropica, background information on Typhoid fever and other salmonellosis for medical professionals
- CDC yellow book, Typhoid & Paratyphoid Fever (CDC, 2024)
- Factsheet Typhoid (WHO, 2023)
References
- Medasso, gezondheidsadviezen voor reizigers, laatste update 2016 – 2017
- ECDC, Typhoid and paratyphoid fever, Annual Epidemiological Report for 2019
- CATMAT Statement on international travellers and typhoid (2014)
- GBD 2017 Typhoid and Paratyphoid Collaborators. The global burden of typhoid and paratyphoid fevers: a systematic analysis for the Global Burden of Disease Study 2017. Lancet Infect Dis. 2019;19(4):369-381
- Date KA, Newton AE, Medalla F, et al. Changing Patterns in Enteric Fever Incidence and Increasing Antibiotic Resistance of Enteric Fever Isolates in the United States, 2008-2012. Clin Infect Dis. 2016;63(3):322-329