Typhoid fever and paratyphoid fever are life-threatening illnesses caused by Salmonella serotype Typhi and Salmonella serotype Paratyphi, respectively.

Most people in the United States with typhoid fever or paratyphoid fever become infected while traveling abroad, most often to countries where these diseases are common.

There is an ongoing outbreak of extensively drug-resistant typhoid fever in Pakistan. Travelers to Pakistan and other South Asian countries should take precautions.

Mary Mallon was an Irish immigrant who worked as a cook in New York in the early 20^th century. Over seven years, from 1900 to 1907, Mallon worked for a number of different households, unknowingly spreading illness to the people who lived in each one. In 1906, one family hired George Soper, an expert in typhoid fever epidemics, to determine the cause of the illnesses in their household. Eventually, Soper tracked Mallon down and directly linked 22 cases of typhoid fever to her. He discovered that Mallon was a carrier for typhoid but was immune to it herself. Although active carriers had been recognized before, this was the first time that an asymptomatic carrier of infection had been identified.

Because she herself had never been ill, Mallon found it difficult to believe she could be the source of the illness. She fled from Soper and the authorities because she did not want to be quarantined or forced to give up her profession, which was relatively well paid for someone with her background. However, Mallon was eventually caught and kept in an isolation facility in the Bronx, where she remained until 1910, when the New York health department released her under the condition that she never again work with food. Unfortunately, Mallon did not comply, and she soon began working as a cook again. After new cases began to appear that resulted in the death of two individuals, the authorities tracked her down again and returned her to isolation, where she remained for 23 more years until her death in 1938. Epidemiologists were able to trace 51 cases of typhoid fever and three deaths directly to Mallon, who is unflatteringly remembered as “Typhoid Mary.”

The Typhoid Mary case has direct correlations in the health-care industry. Consider Kaci Hickox, an American nurse who treated Ebola patients in West Africa during the 2014 epidemic. After returning to the United States, Hickox was quarantined against her will for three days and later found not to have Ebola. Hickox vehemently opposed the quarantine. In an editorial published in the British newspaper The Guardian, Hickox argued that quarantining asymptomatic health-care workers who had not tested positive for a disease would not only prevent such individuals from practicing their profession, but discourage others from volunteering to work in disease-ridden areas where health-care workers are desperately needed.

What is the responsibility of an individual like Mary Mallon to change her behavior to protect others? What happens when an individual believes that she is not a risk, but others believe that she is? How would you react if you were in Mallon’s shoes and were placed in a quarantine you did not believe was necessary, at the expense of your own freedom and possibly your career? Would it matter if you were definitely infected or not?

Typhoid fever and paratyphoid fever are common in many parts of the world.

Typhoid fever and paratyphoid fever are most common in parts of the world where water and food may be unsafe and sanitation is poor. These places include parts of East and Southeast Asia, Africa, the Caribbean, and Central and South America. If you’re traveling to places where typhoid and paratyphoid fever are common, you can take steps to protect yourself from infection.

Two basic actions can protect you:

1. Get vaccinated against typhoid fever. Visit your doctor or a travel clinic at least 2 weeks before traveling to discuss your options.
2. Practice safe eating and drinking habits. Carefully selecting what you eat and drink when you travel is important because typhoid fever vaccines do not work 100% of the time and there isn’t a paratyphoid fever vaccine. Safe eating and drinking will also help protect you from other illnesses, including travelers’ diarrhea, cholera, dysentery, and hepatitis A.

When you travel to areas of risk, remember to “Boil it, cook it, peel it, or forget it.”

• Buy bottled water or bring local water to a rolling boil for 1 minute before you drink it. Bottled carbonated water is safer than uncarbonated water.
• Ask for drinks without ice, unless the ice is made from bottled or boiled water. Avoid popsicles and flavored ices that may have been made with contaminated water.
• Eat foods that have been thoroughly cooked and are still hot and steaming.
• Avoid raw vegetables and fruits that cannot be peeled. Lettuce can remain contaminated even after it is washed.
• Wash your hands with soap and water before eating.
• Avoid foods and beverages from street vendors unless steaming hot.

Typhoid fever and paratyphoid fever have similar symptoms. People usually have a sustained fever that can be as high as 103–104°F (39–40°C). A sustained fever is a fever that does not come and go.

Other symptoms of typhoid fever and paratyphoid fever include

• Weakness
• Stomach pain
• Headache
• Diarrhea or constipation
• Cough
• Loss of appetite

Some people with typhoid fever or paratyphoid fever develop a rash of flat, rose-colored spots.

The only way to know for sure is to have a sample of blood or stool (poop) tested for Salmonella Typhi or Salmonella Paratyphi.

If you have a fever and feel very ill, see a doctor immediately. If you are traveling outside the United States, call the U.S. consulate for a list of recommended doctors. You can also visit an accredited hospital or medical facility. Find out more about getting health care abroad.

Antibiotics treat typhoid fever and paratyphoid fever.

Resistance to antibiotics is increasing in the bacteria that cause these diseases. Resistant bacteria have developed the ability to defeat drugs designed to kill them. Your doctor may order special tests to see if the bacteria causing your infection are resistant. Results from those tests may affect what antibiotic treatment you receive.

People who do not get appropriate antibiotic treatment may have fever for weeks or months and may develop other health problems. People who do not get treatment can die from these health problems.

The danger from typhoid fever or paratyphoid fever doesn’t end when symptoms disappear.

Even if your symptoms seem to go away, you may still be carrying Salmonella Typhi or Salmonella Paratyphi. If so, the illness could return, or you could pass the bacteria to other people. Some people may not be able to return to work until a doctor says they no longer carry the bacteria. These people include healthcare workers, food handlers, and childcare workers.

If you are being treated for typhoid fever or paratyphoid fever, these steps can lower the chance of passing the bacteria to someone else.

• Keep taking antibiotics for as long as the doctor has recommended.
• Wash your hands carefully with soap and water after using the bathroom.
• Do not prepare or serve food for other people.

Vaccination can help prevent typhoid fever. CDC recommends vaccination for people traveling to places where typhoid fever is common, such as South Asia, especially India, Pakistan, or Bangladesh.

Visit a doctor or travel clinic to discuss options.

Two typhoid fever vaccines are available in the United States.

• Oral vaccine: Can be given to people at least 6 years old. It consists of four pills taken every other day and should be finished at least 1 week before travel.
• Injectable vaccine: Can be given to people at least 2 years old and should be given at least 2 weeks before travel.

Typhoid vaccines are not 100% effective. Always practice safe eating and drinking habits to help prevent infection.

Typhoid vaccines lose effectiveness over time. The injectable vaccine requires a booster every 2 years, and the oral vaccine requires a booster every 5 years. If you were vaccinated in the past, ask your doctor if it is time for a booster vaccination. Taking antibiotics will not prevent typhoid fever; they only help treat it.

Basic Information on Typhoid Vaccines Available in the United States

Please note: In December 2020, the maker of the oral typhoid fever vaccine (Ty21a) will temporarily stop making and selling it. This vaccine may be in limited supply or unavailable.

What is typhoid fever?

Typhoid fever and paratyphoid fever are similar diseases caused by bacteria. Salmonella Typhi bacteria cause typhoid fever. Salmonella Paratyphi bacteria cause paratyphoid fever.

People infected with these bacteria can spread them to others. This typically happens when an infected person uses the bathroom and does not wash their hands. The bacteria can stay on their hands and contaminate everything that the person touches, including any food and drinks.

In countries with poor sanitation, the water used to rinse and prepare food and beverages can also be contaminated with these bacteria. Travelers who eat foods or drink beverages contaminated with these bacteria can then get sick.

Typhoid fever and paratyphoid fever cause similar symptoms. People with these diseases usually have a fever that can be as high as 103–104°F (39–40°C). They also may have weakness, stomach pain, headache, diarrhea or constipation, cough, and loss of appetite. Some people have a rash of flat, rose-colored spots. Internal bleeding and death can occur but are rare.

Who is at risk?

Typhoid and paratyphoid fever are most common in parts of the world with poor sanitation. This includes parts of Asia (especially India, Pakistan, and Bangladesh), Africa, the Caribbean, Central and South America, and the Middle East.

People visiting friends or relatives are more likely than other travelers to get typhoid fever because they may stay in the country longer, may be less cautious about the food they eat or the beverages they drink because they eat local food prepared in people’s homes, and may not think to get vaccinated before traveling.

In the United States each year, about 350 people are diagnosed with typhoid fever and 90 people are diagnosed with paratyphoid fever each year. Most of these people travelled internationally.

What can travelers do to prevent typhoid fever?

Getting vaccinated, choosing food and drinks carefully, and washing your hands are the best ways to avoid getting typhoid.

Check if the typhoid fever vaccination is recommended for your destination. Two typhoid vaccines are available in the United States.

• Pill vaccine. People 6 years old and older can take the pill vaccine. Finish taking all four pills (1 pill every other day) at least 1 week before travel.
• Shot vaccine. People 2 years old and older can get the shot vaccine. Get one shot (or a booster shot) at least 2 weeks before travel.

Neither the typhoid pills or shot offer complete protection against infection (50%-80%) and both lose effectiveness over time. Also, there isn’t a vaccine that protects against paratyphoid fever. For these reasons, it’s very important that you also take the following steps to prevent typhoid.

Choose food and drinks carefully

• Only eat foods that are cooked and served hot
• Avoid food that has been sitting on a buffet
• Eat raw fruits and vegetables only if you have washed them in clean water or peeled them
• Only drink beverages from factory-sealed containers
• Avoid ice because it may have been made from unclean water
• Only drink pasteurized milk

Wash your hands

• Wash hands often with soap and water for 20 seconds, especially after using the bathroom and before eating
• If soap and water aren’t available, use an alcohol-based hand sanitizer that contains at least 60% alcohol
• Keep your hands away from your face and mouth

If you traveled and feel sick, particularly if you have a fever, talk to a healthcare provider, and tell them about your travel. Avoid contact with other people while you are sick.

What are typhoid fever and paratyphoid fever?

Typhoid fever is a life-threatening illness caused by Salmonella Typhi bacteria. Paratyphoid fever is a life-threatening illness caused by Salmonella Paratyphi bacteria.

How many people get typhoid fever and paratyphoid fever each year?

Worldwide, typhoid fever affects an estimated 11 to 21 million people and paratyphoid fever affects an estimated 5 million people each year.

In the United States each year, about 350 people are diagnosed with typhoid fever and 90 people are diagnosed with paratyphoid fever each year. These cases do not include people who do not seek medical care, who are not tested for either disease, or whose disease is not reported to CDC. CDC estimates typhoid fever affects 5,700 people in the United States each year. CDC has not made estimates for Salmonella Paratyphi.

Most people diagnosed in the United States have traveled to places where the diseases are most common.

Where are the diseases most common?

Typhoid fever and paratyphoid fever are most common in parts of the world where water and food may be unsafe and sanitation is poor. Travelers to South Asia, especially Pakistan, India, and Bangladesh, should take precautions to prevent infection. Typhoid fever and paratyphoid fever are somewhat less common in East Asia, Africa, the Caribbean, and Central and South America. Both diseases are rare in the United States, Canada, Western Europe, Australia, or Japan.

How are typhoid fever and paratyphoid fever spread?

These diseases are spread through sewage contamination of food or water and through person-to-person contact. People who are currently ill and people who have recovered but are still passing the bacteria in their poop (stools) can spread Salmonella Typhi or Salmonella Paratyphi.

You can get typhoid fever or paratyphoid fever if

• You eat food or drink a beverage that has been touched by a person who is shedding (getting rid of) Salmonella Typhi or Salmonella Paratyphi in their poop and who has not washed their hands thoroughly after going to the bathroom.
• Sewage contaminated with Salmonella Typhi or Salmonella Paratyphi gets into water you drink.
• Sewage contaminated with Salmonella Typhi or Salmonella Paratyphi gets into water used to rinse food you eat raw.

What happens if you eat or drink something contaminated with Salmonella Typhi or Salmonella Paratyphi?

If you consume a food or drink contaminated with Salmonella Typhi or Salmonella Paratyphi, the bacteria can multiply and spread into the bloodstream, causing typhoid fever or paratyphoid fever.

How can I protect myself from typhoid fever and paratyphoid fever?

If you are planning to travel outside the United States, you should do the following:

• Get vaccinated against typhoid fever (there is no vaccine against paratyphoid fever).
• Find out how to avoid getting sick from food and drinks.

Can animals spread typhoid fever or paratyphoid fever to people?

No. Salmonella Typhi and Salmonella Paratyphi live only in humans.

Animals can spread other kinds of Salmonella to humans, so it’s important to wash your hands after contact with animals, their poop, or places where animals live, feed, or roam.