Typhoid fever is a serious systemic infection caused by the bacterium Salmonella enterica serotype Typhi. This illness causes a sustained high fever and gastrointestinal issues. The bacteria primarily live in humans and are shed through feces and, less commonly, urine. An estimated 9 million people get sick from typhoid and 110,000 people die from it worldwide every year.
Transmission and High-Risk Regions
The primary mode of transmission for typhoid fever is the fecal-oral route, occurring when a person ingests food or water contaminated with fecal matter from an infected individual. In regions with inadequate sanitation, contaminated community water supplies are a frequent source of widespread outbreaks. In areas with better sanitation, the disease is more often spread by food handlers who are carriers of the bacteria and do not practice proper hygiene.
Humans are the only natural reservoir for Salmonella Typhi, and the spread is aided by asymptomatic carriers who transmit the bacteria without showing symptoms. One of the most famous historical examples was Mary Mallon, a cook in early 20th-century New York who was an asymptomatic carrier and unknowingly infected numerous people.
Typhoid fever is endemic in many parts of the world, with the highest risk found in South Asia, Africa, and parts of Latin America. Travelers visiting these areas, particularly those visiting friends and relatives, are at an increased risk as they may be less cautious about food and water safety. Even short trips of less than a week can lead to infection in highly endemic locations.
Symptoms and Disease Progression
The onset of typhoid symptoms usually begins 6 to 30 days after exposure to the bacteria. The illness often progresses in stages, with the initial phase marked by a gradually rising fever, headache, weakness, and a dry cough. Loss of appetite is also common during this early period, and the fever can become progressively higher over several days.
If the infection is not treated, the second week brings a sustained high fever, which can reach up to 104°F (40°C). Abdominal pain becomes more pronounced, and patients may experience either constipation or diarrhea. A characteristic, though not universal, symptom that can appear during this stage is the development of “rose spots,” which are small, faint pink spots on the chest and abdomen.
By the third week, the illness can become severe, and the risk of serious complications increases significantly. The high fever persists, and patients may become delirious or confused. Potential complications include intestinal bleeding or a perforation (a hole) in the small intestine, which can be life-threatening. Other complications include inflammation of the heart muscle, pneumonia, and bone infections.
Diagnosis and Treatment
A diagnosis of typhoid fever is suspected based on a patient’s symptoms, recent travel history, and medical evaluation. To confirm the diagnosis, laboratory tests are conducted to isolate the S. Typhi bacteria from the patient’s body fluids or tissues. The most common method is a blood culture, though stool, urine, and bone marrow cultures can also detect the bacteria.
The standard treatment for typhoid fever is a course of antibiotics. The choice of antibiotic can depend on the geographic area where the infection was acquired, as some strains have developed resistance to certain drugs. Common antibiotics used include fluoroquinolones, cephalosporins, and macrolides. Patients must complete the entire prescribed course of medication, even if they start to feel better, to ensure all bacteria are eliminated.
A growing global health concern is the emergence of antibiotic-resistant strains of S. Typhi. Some strains are now resistant to multiple antibiotics, making treatment more complicated and expensive. This resistance complicates disease management and underscores the need for targeted treatment. In severe cases, hospitalization may be necessary for supportive care, including intravenous fluids and nutrition.
Prevention Methods
Prevention combines vaccination with safety precautions. Vaccination is recommended for individuals traveling to high-risk areas. There are two main types of typhoid vaccines available: an injectable vaccine given as a single shot and an oral vaccine administered in a series of capsules. These vaccines are not 100% effective, meaning food and water precautions remain necessary.
Food and Water Safety
Adhering to safety guidelines is the most effective way to avoid infection. A helpful rule of thumb is to “boil it, cook it, peel it, or forget it.” Key practices include:
- Consuming only foods that have been thoroughly cooked and are served hot.
- Eating only fruits that you have washed and peeled yourself.
- Avoiding raw vegetables, salads, and food from street vendors unless it is verifiably fresh and hot.
- Drinking only water that is bottled and sealed or has been boiled for at least one minute.
- Avoiding ice in drinks unless you are certain it was made from safe water.
- Washing hands frequently and thoroughly with soap and water, especially after using the toilet and before handling food.
When soap and water are not available, an alcohol-based hand sanitizer is a good alternative.