Typhoid

Typhoid fever is an infection you get by swallowing the bacterium Salmonella enterica serotype Typhi. It’s a type of enteric fever, related to paratyphoid fever. The bacteria only live in humans—no animals carry them—and you catch it by eating or drinking something contaminated with the feces of an infected person. Symptoms show up six to 30 days after exposure and can range from mild to severe. Typically, a high fever comes on slowly over several days, along with weakness, belly pain, constipation, headaches, and sometimes mild vomiting. Some people get a rash of rose-colored spots. In serious cases, confusion can set in. Without treatment, the illness can drag on for weeks or months, and the chance of dying can be as high as 20%. Diarrhea can be severe but isn’t common. Some people carry the bacteria without getting sick, but they can still spread it.

The bacteria grow in the intestines, Peyer’s patches, lymph nodes, spleen, liver, gallbladder, bone marrow, and blood. People who haven’t been exposed before and drink or eat contaminated water or food are most at risk. Poor sanitation and limited access to clean water increase the danger. This Salmonella Typhi is different from the bacteria that cause typical food poisoning (salmonellosis).

Doctors diagnose typhoid by growing the bacteria from patient samples or by checking the blood for an immune response. Newer methods look at changes in small molecules in the blood that might point specifically to typhoid. But in places where the disease is most common, diagnostic tools aren’t very accurate or specific. The time it takes to get a proper diagnosis, growing antibiotic resistance, and the cost of testing all strain under-resourced healthcare systems.

A vaccine can prevent about 40–90% of cases in the first two years, and it may offer some protection for up to seven years. It’s recommended for people at high risk or those traveling to areas where typhoid is common. Other prevention steps include clean drinking water, good sanitation, and handwashing. Infected people shouldn’t prepare food for others until they’re confirmed clear. Antibiotics like azithromycin, fluoroquinolones, or third-generation cephalosporins are used for treatment, but resistance to these drugs is making treatment harder.

In 2015, there were 12.5 million new cases worldwide, mostly in children. Typhoid dropped in developed countries in the 1940s thanks to better sanitation and antibiotics. About 400 cases are reported each year in the U.S., with an estimated 6,000 people carrying the infection. In 2015, around 149,000 people died from it—down from 181,000 in 1990. With treatment, the death rate is between 1% and 4%.

Typhus is a different disease caused by unrelated bacteria. Because their symptoms are similar, people didn’t tell them apart until the 1800s. The name “typhoid” means “resembling typhus.”

Signs and symptoms usually follow three stages in untreated cases, each lasting about a week. In the first week, fever rises slowly with a slow heart rate relative to the fever (Faget sign), along with malaise, headache, and cough. A quarter of patients get nosebleeds. Belly pain is possible. White blood cell counts drop, and blood cultures are positive for the bacteria. The Widal test is usually negative. In the second week, the person is often too weak to get up, with a high, steady fever around 39–40.5°C and a slow heart rate. Delirium can occur—sometimes calm, sometimes agitated—which earned typhoid the nickname “nervous fever.” About a third of patients develop rose spots on the lower chest and belly. Rattling breath sounds are heard in the lungs. The belly is swollen and tender in the lower right area, with rumbling noises. Diarrhea or constipation may occur. The spleen and liver are enlarged and tender, and liver enzymes are high. The Widal test is strongly positive. Blood cultures may still be positive. In the third week, fever stays very high with little change over 24 hours. Dehydration and malnutrition set in, and the patient is delirious. A third of people get a macular rash on the trunk. Complications can include intestinal bleeding from congested Peyer’s patches (serious but usually not fatal), intestinal perforation in the lower small intestine (often fatal, sometimes without warning until sepsis or peritonitis develops), pneumonia, acute bronchitis, encephalitis, neuropsychiatric symptoms like muttering delirium or picking at bedclothes, and metastatic abscesses.