Alerts and Notices
SynopsisTyphoid and paratyphoid fevers (enteric fever) occur from infection with Salmonella enterica serotype typhi and Salmonella enterica serotype paratyphi A, B, and C, respectively. These infections are found in most parts of the world, with lower rates in industrialized regions (United States, Canada, Western Europe, and Japan). Unlike nontyphoidal Salmonella, typhoid and paratyphoid are strictly human diseases and transmitted via fecal-oral transmission between humans. Typhoid and paratyphoid are clinically indistinguishable from each other, and the term "enteric fever" is used as a unifying term to encompass both conditions.
The incubation period for typhoid fever is 6-30 days, and for paratyphoid fever it is 1-10 days. The initial symptoms of typhoid and paratyphoid fevers include the acute or gradual onset of abdominal pain and tenderness, fever, chills, sweating, headache, anorexia, weakness, cough, sore throat, dizziness, and myalgias. Fever develops slowly beginning as low-grade and rising to sustained temperatures of 102°F-104°F (39°C-40°C) by the fourth day. This usually progresses to a severe illness with bacteremia and high fever that may last for weeks. Hepatosplenomegaly is common. Some patients will develop erythematous macules and papules on the trunk (rose spots), and some will suffer altered mental status. Intestinal hemorrhage and bowel perforation are rare, potentially lethal complications that may occur after 2 weeks of illness. Meningitis, chondritis, cholecystitis, pyelonephritis, orchitis, typhoid hepatitis, pneumonia, localized abscesses, endocarditis, and myocarditis are further rare complications.
About 350 culture-confirmed cases of typhoid fever and 90 culture-confirmed cases of paratyphoid fever were reported annually to the US Centers for Disease Control and Prevention (CDC) National Typhoid and Paratyphoid Fever Surveillance (NTPFS) system during 2008-2015. Most cases in the United States are associated with travel to East Asia and South Asia, though these infections can also occur in travelers to Africa, the Caribbean, Central and South America, and the Middle East. In the United States, 75% of cases occur in patients aged younger than 30 years. Untreated, enteric fever carries a 10%-20% mortality rate. In 15%-20% of treated patients, there is relapse after 2 weeks. Reinfection and chronic carriage can occasionally occur.
The CDC has classified drug-resistant nontyphoidal Salmonella and drug-resistant Salmonella serotype typhi as serious infections.
See salmonellosis for discussion of serotypes Salmonella typhimurium and Salmonella enteritidis.
A01.00 – Typhoid fever, unspecified
A01.4 – Paratyphoid fever, unspecified
4834000 – Typhoid fever
85904008 – Paratyphoid fever
Differential Diagnosis & Pitfalls
- In patients who have traveled to an area endemic for S typhi and return with fever, also consider malaria. Other conditions that can mimic the illness include amebiasis, dengue fever, chikungunya, Zika virus infection, leishmaniasis (Old World, New World), leptospirosis, melioidosis, and trypanosomiasis.
- Acute bacterial gastroenteritis (Campylobacter, Shigella, Escherichia coli O157:H7)
- Tuberculosis – Can present as a prolonged febrile illness; diarrhea (and dysentery) is not expected.
- Endemic typhus – May be difficult to distinguish from typhoid fever.
- Bacterial abscess – Can present as a prolonged febrile illness.
- Endocarditis – Can present as a prolonged febrile illness.
- Q fever
Patient Information for Enteric fever
OverviewTyphoid fever is the name given to the illness caused by the bacterium Salmonella typhi, a member of the Salmonella family. Typhoid fever is spread through food and water contaminated by animal and human feces. Typhoid fever is very rare in the United States and other developed nations, and it is more common in underdeveloped nations, particularly Latin America, Asia, and Africa. When traveling to underdeveloped areas, a good way to remember what foods and beverages are safe is to think of the following: If you cannot boil it (to kill bacteria), peel it (to remove bacteria) or cook it (to kill bacteria), do not eat it. When traveling to areas without clean drinking water, also remember to avoid ice cubes, which may be made with contaminated water, and to check the seal on all bottled water that you purchase (as the water bottle may have been refilled with unclean water). Some travelers drink only carbonated water in order to avoid this issue.
The longer typhoid fever symptoms go untreated, the higher the risk of complications, including the spread of the bacteria to the blood (sepsis) and death.
Who’s At RiskAnyone who comes into contact with contaminated food or water is at risk of developing typhoid fever; the very young, very old, and those who are immunocompromised are at much greater risk of developing more severe disease.
Signs & SymptomsThe distinguishing characteristics of typhoid fever illness are high fever (temperature as high as 40°C [104°F]), feeling generally weak and achy (malaise), headache, loss of appetite, rash, and sometimes diarrhea or constipation. These symptoms usually begin within hours to days of ingesting the contaminated substance and may go away on their own within a week but, if left untreated, may last for weeks.
Symptoms of typhoid fever are as follows:
- High fever (temperature of 38-40°C [102-104°F])
- Malaise (achiness and weakness)
- Abdominal pain
- Change in stool output, such as constipation or diarrhea
- Rarely, a flat (not raised) rash of dark pink spots
Self-Care GuidelinesIf you have traveled to an area of the world where typhoid is endemic and you exhibit the symptoms listed above, seek medical attention and let your doctor know about your travel history. Until you can see the doctor, try to stay hydrated, preferably with a liquid that contains some sugar and electrolytes, such as a sports drink. Drink at least 2 liters of this liquid a day. Eat a bland (not spicy) low-fat diet, avoiding milk and dairy products until the diarrhea improves. Practice good hand hygiene, as the bacteria can be easily spread from one person to another through fecal contamination.
When to Seek Medical CareFor any illness with high fever, rash, and gastrointestinal symptoms, it is a good idea to consult a doctor. There are very few cases of typhoid fever diagnosed in the United States every year, and most are in recently returned international travelers. Make sure to tell your doctor where you have recently been, or if you are traveling when the symptoms begin, seek medical care wherever you are. Typhoid fever can be difficult to diagnose by symptoms alone, but your doctor can easily test your stool for the presence of the S. typhi bacterium.
TreatmentsYour doctor will prescribe a regimen of antibiotics, after stool or blood testing has shown the S. typhi bacterium is present. There is a vaccine available for people traveling to regions where S. typhi is endemic. The vaccine is not available for children under the age of 6 and is not safe for immunocompromised people, however, so this group of travelers must be extra vigilant to avoid contaminated foods and water.