Enteric Fever (Typhoid and Paratyphoid)

What enteric fever is

"Enteric" means relating to the intestine. The bacteria enter through the gut, pass through its wall, and spread via the lymph system and bloodstream to the liver, spleen, bone marrow and gallbladder. Unlike ordinary salmonella food poisoning, which stays in the gut and causes diarrhea, enteric fever is a whole-body illness with high fever.

Humans are the only host. Infection follows eating or drinking something contaminated by an infected person or by a chronic carrier, someone who keeps shedding bacteria (often from the gallbladder) without feeling ill. Doctors use the term "enteric fever" because typhoid and paratyphoid look the same at the bedside and are treated the same way until the lab identifies the organism.

Typhoid vs paratyphoid fever

For details specific to each, see typhoid fever and paratyphoid fever.

Enteric fever symptoms

Symptoms usually build over the first week rather than starting abruptly:

• Fever that rises step by step, often reaching 39 °C to 40 °C (102 °F to 104 °F), worse in the evening
• headache, tiredness and body aches
• poor appetite and stomach pain
• constipation in adults, diarrhea more often in children and people with HIV
• dry cough
• a relatively slow pulse for the height of the fever, a classic but inconsistent sign
• "rose spots": faint pink spots on the chest or belly in a minority of people
• an enlarged liver and spleen

Untreated, the illness worsens in the second week, with exhaustion, delirium or a dazed state (the "typhoid state"). Complications typically appear in the third week. Recovery, if it happens without treatment, takes weeks to months.

Complications

• Intestinal bleeding and perforation: ulcers in the small intestine can bleed or burst, causing peritonitis. This is a surgical emergency. See intestinal perforation.
• Encephalopathy: confusion, agitation or coma.
• Hepatitis, myocarditis, pneumonia and kidney problems.
• Relapse: in up to about 1 in 10 people, 1 to 3 weeks after recovery.
• Chronic carriage: a few percent of people, more often those with gallstones, carry the bacteria for a year or more.

Diagnosis

Enteric fever is easily confused with malaria, dengue fever, rickettsial infection and leptospirosis, so testing matters.

• Blood culture: the main test. It is positive in about 40% to 80% of cases, highest in the first week and before antibiotics. Several samples raise the yield.
• Bone marrow culture: the most sensitive test, used when blood cultures are negative but suspicion remains high.
• Stool and urine cultures: become positive later, and help identify carriers.
• Antibiotic sensitivity testing: essential because resistance is widespread.
• Blood tests: may show a normal or low white count, raised liver enzymes and low platelets.
• The Widal test measures antibodies but gives many false positives and false negatives. It should not be relied on alone. Rapid antibody tests also have limited accuracy.

Always tell your doctor exactly where you traveled and when. Malaria testing is usually done at the same time in returned travelers with fever.

Treatment

Antibiotics shorten the illness from weeks to days and sharply reduce complications. The choice depends on where the infection was acquired:

• Fluoroquinolone resistance (such as to ciprofloxacin) is now common, especially in infections from South Asia, so these drugs are usually not used first for travelers from that region.
• Extensively drug-resistant (XDR) typhoid, first reported in Pakistan in 2016, resists most oral antibiotics except azithromycin. Carbapenems such as meropenem are used for severe XDR cases.
• Common choices: oral azithromycin for uncomplicated cases, and IV ceftriaxone or a carbapenem for severe illness or when resistance is likely, adjusted once sensitivities return.

Fever often takes 3 to 6 days to settle even with the right antibiotic. Severe cases may need fluids, high-dose steroids for typhoid encephalopathy, and surgery for perforation. Complete the full course of antibiotics to reduce relapse.

Carriers can often be cleared with a prolonged antibiotic course. Gallbladder removal is sometimes needed when gallstones are present.

Returning to work or school

In the US and UK, food handlers, healthcare workers and young children who have had enteric fever may need repeat negative stool samples before returning, as directed by local public health authorities.

Prevention

• Typhoid vaccine: an injected vaccine (one dose, protects about 2 years) or an oral live vaccine (capsules, protects about 5 years). Both protect only partly, about 50% to 80%, and not against paratyphoid. Get it at least 1 to 2 weeks before travel.
• Food and water: drink bottled, boiled or treated water. Avoid ice, raw salads, unpeeled fruit, street food that is not freshly cooked and hot, and unpasteurized dairy.
• Hand hygiene: wash hands with soap after using the toilet and before eating.

Frequently asked questions

Is enteric fever the same as typhoid?

Not exactly. Enteric fever covers both typhoid fever (Salmonella Typhi) and paratyphoid fever (Salmonella Paratyphi). The illnesses look alike and are treated the same way, so doctors often use the umbrella term until the lab confirms which one it is.

How is enteric fever spread?

It spreads through food or water contaminated with the feces of an infected person or carrier. It does not spread through the air. Poor sanitation, unsafe drinking water and food prepared by an infected person without good hand-washing are the main routes.

Is the Widal test reliable for enteric fever?

No. The Widal test often gives false positives, especially in areas where typhoid is common or after vaccination, and it can be negative early in illness. A blood culture is the recommended test, and bone marrow culture is the most accurate.

How long does enteric fever last?

With effective antibiotics, most people feel better within a week, though fever can take several days to settle and tiredness may linger for weeks. Without treatment, illness typically lasts 3 to 4 weeks or longer and carries a significant risk of serious complications.

Does the typhoid vaccine protect against paratyphoid?

No, or only very slightly. Current typhoid vaccines target Salmonella Typhi. There is no licensed paratyphoid vaccine, so safe food and water habits remain important even if you have been vaccinated.