Typhoid infections in the US mostly follow travel, so tell your doctor where you went

If you travel abroad, you probably already know that typhoid is something to plan for. A new CDC study backs that up and adds one useful detail: when typhoid infections do show up in the US, most of them are linked to a trip, and doctors do best when they know where you’ve been.

The study also found that a common antibiotic, ciprofloxacin, often does not work against these bacteria. That is why doctors now match the medicine to lab results instead of guessing.

How the study worked

CDC researchers looked at 2,342 lab-confirmed cases of typhoid and paratyphoid fever (together called enteric fever) diagnosed across the US from 2016 to 2020. It was a cross-sectional study, which means it takes a snapshot of the cases rather than following people over time. It was published Oct. 1, 2026, in JAMA Network Open. It covers only cases that were confirmed and reported, and only through 2020.

What they found

The link to travel was strong. About 4 in 5 patients (81.9%, or 1,853 of 2,217 with the information) had traveled or lived abroad within 30 days before getting sick. The typical patient was 25 years old.

The second finding is about treatment. Ciprofloxacin did not work well against most of the bacteria that were tested:

• Typhoid: 78.4% were not susceptible (1,061 of 1,354).
• Paratyphoid A: 94.2% were not susceptible (258 of 274).

For typhoid, more than 15% of the bacteria also resisted ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole. Ceftriaxone, a strong antibiotic given by IV, failed against 5.5% of typhoid samples (74 samples). Only 1 typhoid sample (0.1%) resisted azithromycin. None of the paratyphoid samples resisted these medicines.

The reassuring part is that these medicines still work for many people, and azithromycin stood out as holding up well. The takeaway for doctors is to check which antibiotic works for each patient’s bacteria, rather than assuming.

What does “not susceptible” mean?

It means the antibiotic does not work well against that particular germ in the lab. Bacteria change over time, and some learn to survive medicines that used to stop them. A lab test shows which medicines still work, so your doctor can choose the right one.

This is also why the study’s authors say ciprofloxacin should not be the first pick for most typhoid and paratyphoid cases tied to travel. Doctors often start treatment before lab results come back. Knowing your travel history helps them choose a better starting point.

What you can do today

If you have a trip coming up to South Asia, Africa or Latin America, where typhoid is more common, call a travel clinic this week and ask about the typhoid vaccine. Ask early, at least a couple of weeks before you leave. Many pharmacies and your local health department can point you to a clinic. On the trip, stick to safe water and food that is cooked and served hot, and wash your hands often. If you get a fever during or after the trip, see a doctor and tell them right away where you traveled.