What is Typhoid Fever?
Typhoid fever is a systemic, febrile disease contracted by ingesting contaminated food or water. It is unique to humans and commonly found where sanitation is deficient. Historically, typhoid fever was a major cause of illness and death until the advent of modern antibiotics. Millions of people are still affected by typhoid fever every year, especially people living in low- and middle-income countries and international travelers.
What Causes Typhoid Fever?
Typhoid fever is caused by infection with the bacteria Salmonella enterica serovar Typhi. S. Typhi is spread from infected to susceptible people via the fecal-oral transmission route. Important risk factors for infection with S. Typhi include lack of access to improved sanitation and clean drinking water. A small proportion of infected individuals (2-5%) in endemic regions will develop a chronic gall bladder infection and serve as asymptomatic reservoirs of S. Typhi, potentially infecting contacts for years.
What are the Symptoms of Typhoid Fever?
Typhoid fever exhibits variable clinical features, including non-specific symptoms such as diarrhea and vomiting or even respiratory symptoms. This variable profile can make typhoid fever difficult to diagnose. In a typical case of typhoid fever, symptoms will begin 10-14 days after exposure to the bacteria. Initial features can include a low-grade fever, headache, myalgia, and a dry, bronchitic cough. The fever may rise stepwise to a persistent, high grade (103° to 104°F) in the second week of the disease.
Serious complications occur in up to 10–15% of typhoid fever patients, especially in those who have been ill longer than two weeks and have not received proper treatment. Complications include gastrointestinal bleeding and perforation. Intermittent confusion, dizziness and other neurological manifestations can also occur in severe cases.
What are Trends in Typhoid Epidemiology?
Over the last 20 years, the burden of typhoid fever has been consistently high. Recent studies estimate that, globally, there are 17.8 million cases (6.9–48.4 million) of typhoid fever and 129,000 deaths (75,000–208,000) each year. Most cases occur in sub-Saharan Africa and South Asia, but the majority of low- and middle-income nations are affected. People from high-income countries contract the illness when traveling to endemic regions.
How Can You Prevent and Treat Typhoid Fever?
S. Typhi thrives in unsanitary conditions. The key to prevention is thus access to clean water, improved sanitation, and personal hygiene measures, including safe food practices. Vaccines are available that can help protect against typhoid fever.
Typhoid fever must be promptly treated with antibiotics to prevent relapses and reduce fecal shedding. Doing so can reduce case-fatality rates to below 1%. In most cases, oral antibiotic treatment and bedrest are sufficient for full recovery. Severe cases will need to be admitted to a healthcare setting for monitoring and treatment with parenteral antibiotics. Unfortunately, antimicrobial resistance is growing among S. Typhi strains, undermining the effectiveness of many existing therapies and underscoring the importance of immunization.