Typhoid fever is a serious bacterial infection that spreads through food and water contaminated with the feces of an infected person. It is caused by the bacterium Salmonella enterica serovar Typhi, usually shortened to S. Typhi, and it remains common in parts of the world where clean water and safe sanitation are limited. In the United States, typhoid fever is uncommon and most often picked up during international travel. Unlike a sudden stomach bug, typhoid fever tends to build slowly over days, producing a steadily climbing fever along with headache, deep fatigue, and abdominal discomfort. This guide explains what typhoid fever is, how to recognize its symptoms, how it spreads, how doctors diagnose it with blood and other laboratory tests, and what current treatment, prevention, and research have to offer.
What is typhoid fever?
Typhoid fever is a whole-body infection caused by the bacterium S. Typhi, a close relative of the Salmonella bacteria that cause ordinary food poisoning. After a person swallows the bacteria, the organisms pass through the wall of the intestine and spread through the bloodstream and lymphatic system, which is why the illness affects far more than the gut. Doctors group typhoid together with the milder paratyphoid fever under the umbrella term enteric fever, because both share a similar cause and course.
The disease is a major global health problem. The Centers for Disease Control and Prevention estimates that S. Typhi causes roughly 9 million illnesses worldwide each year, concentrated in South Asia, sub-Saharan Africa, and parts of Southeast Asia, where clean water and sanitation are limited. In the United States there are only about 5,700 cases a year, most of them acquired while traveling. Because it spreads through contaminated food and water, typhoid belongs to the same family of waterborne infections as cholera, and you can read the cholera symptoms, causes, and treatment guide to see how another water-related illness behaves.
Symptoms of typhoid fever
The symptoms of typhoid fever usually appear gradually, most often one to three weeks after a person swallows the bacteria. The hallmark is a fever that climbs a little higher each day in a stepwise pattern, sometimes reaching 103 to 104 degrees Fahrenheit, and that lingers for a week or more if the infection is not treated.
Other common features include a dull headache, aching muscles, a poor appetite, and abdominal pain, along with either constipation or diarrhea depending on the person. Some patients develop a scattering of faint, salmon-colored spots on the chest and abdomen known as rose spots, a slower-than-expected pulse for the height of the fever, and an enlarged liver or spleen that a clinician can sometimes feel during an examination.
| Common symptom | What it usually feels like |
|---|---|
| Prolonged fever | A temperature that rises a little each day and can stay high for a week or longer |
| Headache and body aches | A persistent dull headache with general muscle soreness and weakness |
| Abdominal pain and appetite loss | Stomach discomfort with little interest in food, often with constipation or diarrhea |
| Extreme fatigue | A heavy, worsening tiredness that makes normal activity difficult |
| Rose spots | Faint pink or salmon-colored spots that can appear on the chest and abdomen |
How typhoid fever spreads: causes and risk factors
Typhoid fever spreads by what doctors call the fecal-oral route, meaning the bacteria leave an infected person in their stool and then reach another person’s mouth through contaminated food or water. This can happen when sewage seeps into drinking water, when crops are irrigated with unclean water, or when an infected food handler who has not washed their hands prepares a meal.
Some people who recover from typhoid continue to carry S. Typhi in their gallbladder and shed it in their stool for months or years without feeling sick. These chronic carriers can unknowingly infect others, which is one reason the disease persists in some communities. The greatest risk factor is travel to a region where typhoid is common, especially South Asia, and it helps to review the hepatitis A symptoms, causes, and treatment guide, since that infection spreads through the same contaminated food and water. Because a fever that persists after travel can have several causes, a lingering illness may also lead a doctor to consider the malaria symptoms, causes, and treatment options guide.
Antibiotic resistance in typhoid fever
One of the most important developments in typhoid care is the rise of antibiotic resistance. For decades, older antibiotics such as ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole cured most cases. Strains that resist all three at once are called multidrug-resistant, or MDR, and they spread widely across Asia and Africa, with many later becoming resistant to the fluoroquinolone antibiotics as well.
More recently, extensively drug-resistant strains, known as XDR typhoid, have emerged, most notably in Pakistan. These resist the older first-line drugs, the fluoroquinolones, and most third-generation cephalosporins such as ceftriaxone, leaving only a few effective options. That is why a clinician cannot always predict which antibiotic will work, why laboratory testing of the specific strain matters so much, and why the drugs relied on today, such as azithromycin and the carbapenems, differ from those used in the past.
How typhoid fever is diagnosed
Because the early symptoms of typhoid fever overlap with many other illnesses, laboratory testing is essential to confirm it. The cornerstone of diagnosis is a blood culture, in which a sample of blood is placed in a special medium so any S. Typhi bacteria present can grow and be identified. Blood cultures work best in the first week of illness and also let the laboratory test which antibiotics the strain responds to, information that directly guides treatment. A bone marrow culture is even more sensitive but is used less often because it is invasive, and stool or urine cultures can help later in the illness.
Blood tests do more than grow the bacteria; they also show how the infection is affecting the body. A clinician usually orders a complete blood count that measures your white cells, red cells, and platelets, because typhoid often produces a normal or low white blood cell count rather than the high count seen in many bacterial infections, which helps a doctor understand what a white blood cell count can reveal during an infection. The same panel may show mild anemia. A laboratory may also review a stool culture that can identify the bacteria in the intestines, and because typhoid can inflame the liver, a doctor may check the alanine aminotransferase level that signals liver irritation. The older Widal antibody test is still used in some places but is unreliable, so cultures remain the standard.
| Test | What it shows | Notes |
|---|---|---|
| Blood culture | Live S. Typhi bacteria grown from a blood sample, confirming infection | The main test; most useful in the first week and guides antibiotic choice |
| Bone marrow culture | The bacteria grown from a marrow sample | More sensitive than blood culture but more invasive, so used selectively |
| Stool and urine cultures | Bacteria shed in stool or urine | Often positive later in the illness and useful for detecting carriers |
| Complete blood count | White cells, red cells, and platelets | Supports the diagnosis; often shows a normal or low white cell count and mild anemia |
Treatment and recovery
Typhoid fever is treated with antibiotics, and choosing the right one has become more complicated as resistance has spread. When the infection is caught early and the strain is susceptible, an oral antibiotic such as azithromycin can treat uncomplicated cases. More severe illness, or infection with a resistant strain, is often treated in the hospital with an injectable antibiotic such as ceftriaxone, while carbapenem antibiotics such as meropenem are reserved for extensively drug-resistant strains. Whenever possible, doctors tailor the choice to the results of culture and susceptibility testing rather than guessing.
Alongside antibiotics, supportive care helps the body recover, including rest, fluids to prevent dehydration, and good nutrition, with intravenous fluids in the hospital when a person cannot keep enough down. Most people begin to feel better within a few days of starting an effective antibiotic, though full recovery can take one to two weeks, and it is important to finish the entire course so the infection does not return. Because typhoid can be serious and resistance patterns vary by region, anyone with a prolonged fever after travel should see a clinician promptly rather than trying to manage the illness alone.
Prevention
Preventing typhoid rests on two pillars: vaccination and safe food and water habits. Two vaccines are available in the United States for travelers to areas where typhoid is common. One is an injectable vaccine made from the purified Vi capsular sugar of the bacterium, given as a single shot for people aged two and older, with a booster roughly every two years. The other is an oral live vaccine, taken as a series of capsules for people aged six and older, with a booster about every five years. A newer typhoid conjugate vaccine, which links the Vi sugar to a carrier protein, provides longer-lasting protection and can be given to young children; it is now used in routine childhood immunization programs in several endemic countries.
No typhoid vaccine is fully protective, so careful food and water choices still matter, especially while traveling. The following habits lower the risk of infection.
- Drink only bottled, boiled, or properly treated water, and avoid ice unless it was made from safe water.
- Eat foods that are cooked and served hot, and be cautious with raw fruits and vegetables you did not peel yourself.
- Avoid food from street vendors when you cannot be sure how it was prepared or stored.
- Wash your hands with soap and water before eating and after using the bathroom, using hand sanitizer when soap is unavailable.
- Talk with a travel clinic about typhoid vaccination several weeks before visiting a region where the disease is common.
Complications and long-term outlook
With prompt antibiotic treatment, most people recover from typhoid fever completely, and deaths are rare. The danger lies in leaving the infection untreated, when serious complications can develop around the third week of illness. The most feared of these are a hole in the wall of the intestine, called intestinal perforation, and bleeding from the intestine, both of which are medical emergencies that require urgent care.
Because the bacteria travel through the bloodstream, a severe infection can trigger the dangerous whole-body reaction explained in this sepsis guide, and less commonly it can inflame the heart muscle or the brain. A smaller number of people become chronic carriers, harboring the bacteria in the gallbladder long after they feel well, which is why follow-up testing and, in some cases, longer treatment may be recommended. Overall, the outlook is very good when typhoid is recognized and treated early, which makes prompt medical attention for a persistent fever the single most important step.
Latest scientific advances in typhoid fever research
The most encouraging recent progress against typhoid has come from vaccines. According to research indexed in PubMed, a 2025 systematic review and meta-analysis in Vaccine pooled real-world data from typhoid-endemic countries and found that a single dose of a typhoid conjugate vaccine prevented culture-confirmed typhoid with an effectiveness of about 87 percent, and prevented extensively drug-resistant typhoid with an effectiveness of roughly 97 percent (Haposan et al., 2025). What this means for you: the typhoid conjugate vaccine is now a proven tool that works even against the hardest-to-treat strains, so if you are traveling to or living in a region where typhoid circulates, it is worth asking a clinician whether vaccination is right for you or your children.
At the same time, researchers are tracking the resistant strains that make treatment harder. A 2025 study in Diagnostic Microbiology and Infectious Disease examined S. Typhi grown from blood samples in Khyber Pakhtunkhwa, Pakistan, and found that about 72 percent of isolates were multidrug-resistant and roughly 22 percent were extensively drug-resistant, while the antibiotic meropenem still worked against most of them (Ahmad et al., 2025). A separate 2025 genomic study in Microbiology Spectrum analyzed XDR strains from Gujarat, India, and reported that certain laboratory combinations pairing a cephalosporin with a beta-lactamase inhibitor were effective against these resistant bacteria in the lab (Akshay et al., 2025). What this means for you: these are early surveillance and laboratory findings rather than new prescriptions, but they explain why doctors now rely on culture-guided antibiotics, and why treatment should always follow local testing of the specific strain.
Glossary of key terms
| Term | Definition |
|---|---|
| Salmonella Typhi (S. Typhi) | The specific bacterium that causes typhoid fever. |
| Enteric fever | The umbrella term for typhoid and the milder paratyphoid fever. |
| Fecal-oral route | Spread of bacteria from an infected person’s stool to another person’s mouth through food or water. |
| Chronic carrier | A recovered person who keeps shedding the bacteria, often from the gallbladder, without symptoms. |
| Multidrug-resistant (MDR) | A strain resistant to several older first-line antibiotics at once. |
| Extensively drug-resistant (XDR) | A strain resistant to most standard antibiotics, leaving only a few options. |
| Rose spots | Faint pink spots on the chest and abdomen that can appear during typhoid. |
| Typhoid conjugate vaccine (TCV) | A newer vaccine that links the bacterium’s Vi sugar to a protein for longer-lasting protection. |
Frequently asked questions
What are the early symptoms of typhoid fever?
Typhoid usually begins gradually, one to three weeks after exposure. The earliest sign is often a fever that climbs a little higher each day, joined by headache, tiredness, muscle aches, and a fading appetite. Abdominal pain with either constipation or diarrhea is common, and some people develop faint rose-colored spots on the chest and abdomen. Because these signs are easy to mistake for other illnesses, a prolonged fever after travel deserves medical attention.
How do you get typhoid fever?
You get typhoid by swallowing food or water contaminated with the S. Typhi bacteria, which are shed in the stool of an infected person. This can happen through unsafe drinking water, food washed or irrigated with contaminated water, or meals prepared by someone who carries the bacteria and has not washed their hands. Most cases in the United States are acquired while traveling in regions where the disease is common.
Which antibiotics treat typhoid fever, and why is drug resistance a concern?
Doctors treat typhoid with antibiotics such as azithromycin for uncomplicated cases, ceftriaxone for more severe illness, and carbapenems such as meropenem for extensively drug-resistant strains. Drug resistance is a growing concern because many strains no longer respond to older medicines, and some, called XDR typhoid, resist most standard options. This is why laboratory testing of the specific strain is used to guide the choice of antibiotic.
How is typhoid fever diagnosed with a blood test?
The main test is a blood culture, in which blood is incubated so any S. Typhi bacteria can grow and be identified, ideally in the first week of illness, and the same culture shows which antibiotics will work. A complete blood count often reveals a normal or low white cell count and mild anemia, and stool or urine cultures can add information later in the illness.
Is there a typhoid vaccine, and how long does it protect you?
Yes. Two typhoid vaccines are available in the United States: an injectable vaccine given as a single dose with a booster about every two years, and an oral vaccine taken as capsules with a booster about every five years. A newer typhoid conjugate vaccine offers longer protection and is used in childhood programs in many endemic countries. No vaccine is fully protective, so safe food and water habits remain important.
Can someone spread typhoid fever without feeling sick?
Yes. Some people who recover become chronic carriers, keeping the bacteria in the gallbladder and shedding them in their stool for months or years without any symptoms. These carriers can pass the infection to others, especially if they handle food. Careful handwashing and, when needed, testing and treatment can reduce this risk, which is one reason typhoid persists in some communities.
Sources
- Centers for Disease Control and Prevention — About Typhoid Fever and Paratyphoid Fever — CDC Typhoid Fever, 2024 — cdc.gov
- Centers for Disease Control and Prevention — Treating Typhoid Fever and Paratyphoid Fever — CDC Typhoid Fever, 2024 — cdc.gov
- Cleveland Clinic — Typhoid Fever: Causes, Symptoms and Treatment — Cleveland Clinic Health Library, 2023 — my.clevelandclinic.org
- Mayo Clinic — Typhoid fever: Diagnosis and treatment — Mayo Clinic, 2023 — mayoclinic.org
- MedlinePlus, National Library of Medicine — Typhoid fever — MedlinePlus Medical Encyclopedia, reviewed 2023 — medlineplus.gov
- Haposan JH, Icanervilia AV, Watts E, et al. — Real-world vaccine effectiveness of typhoid conjugate vaccine in children and adolescents: a systematic review and meta-analysis — Vaccine, 2025 — doi.org/10.1016/j.vaccine.2025.127872
- Ahmad J, Khan MA, Atif M, et al. — Incidence and antimicrobial resistance profile of multi-drug resistant Salmonella typhi isolated from blood samples in Khyber Pakhtunkhwa, Pakistan — Diagnostic Microbiology and Infectious Disease, 2025 — doi.org/10.1016/j.diagmicrobio.2025.117122
- Akshay SD, Upadhyaya H, Shukla N, et al. — Comprehensive analysis of extensive drug-resistant S. Typhi in the Gujarat region, India: genomic findings and prospective alternative therapy — Microbiology Spectrum, 2025 — doi.org/10.1128/spectrum.02540-24
Further reading
- Compare typhoid with another travel-related fever by reading this guide to dengue fever symptoms, causes, and treatment.
- Learn how a travel vaccine prevents another serious infection by reading this guide to yellow fever symptoms, causes, and treatment.
- Understand a more common cause of fever and diarrhea by reviewing this guide to gastroenteritis symptoms, causes, and treatment.
- Explore how another laboratory culture is interpreted by reading this guide to what a urine culture reveals.
- Build a fuller picture of your own numbers with this guide to reading reference ranges, flags, and trends in a lab report.
Understand your lab results with BloodSense
A diagnosis of typhoid fever rests on laboratory testing, from the blood culture that identifies the bacteria to the complete blood count and liver enzymes that show how the infection is affecting your body. Those same results can be difficult to interpret on your own, especially when a report lists cultures, reference ranges, and values flagged as high or low. BloodSense translates a full lab report into plain language, showing where each marker sits relative to its reference range and helping you understand what a result actually means for your health.
