The infection is often passed on through contaminated food and drinking water, and it is more prevalent in places where handwashing is less frequent. It can also be passed on by carriers who do not know they carry the bacteria.
Annually, there are around 5,700 cases in the United States, and 75 percent of these start while traveling internationally. Globally, around 21.5 million people a year contract typhoid.
If typhoid is caught early, it can be successfully treated with antibiotics; if it is not treated, typhoid can be fatal.
Fast facts on typhoid
Here are some key points about typhoid. More detail is in the main article.
- Typhoid is a common bacterial infection in countries with low incomes.
- Untreated, it is fatal in around 25 percent of cases.
- Symptoms include a high fever and gastrointestinal problems.
- Some people carry the bacteria without developing symptoms
- Most cases reported in the United States are contracted overseas
- The only treatment for typhoid is antibiotics
What is typhoid?
Typhoid is an infection caused by Salmonella typhimurium bacteria that is spread from human to human.
Typhoid is an infection caused by the bacterium Salmonella typhimurium (S. typhi).
The bacterium lives in the intestines and bloodstream of humans. It spreads between individuals by direct contact with the feces of an infected person.
No animals carry this disease, so transmission is always human to human.
If untreated, around 1 in 5 cases of typhoid can be fatal. With treatment, fewer than 4 in 100 cases are fatal.
S. typhi enters through the mouth and spends 1 to 3 weeks in the intestine. After this, it makes its way through the intestinal wall and into the bloodstream.
From the bloodstream, it spreads into other tissues and organs. The immune system of the host can do little to fight back because S. typhi can live within the host's cells, safe from the immune system.
Typhoid is diagnosed by detecting the presence of S. typhi via blood, stool, urine, or bone marrow sample.
Symptoms normally begin between 6 and 30 days after exposure to the bacteria.
The two major symptoms of typhoid are fever and rash. Typhoid fever is particularly high, gradually increasing over several days up to 104 degrees Fahrenheit, or 39 to 40 degrees Celsius.
The rash, which does not affect every patient, consists of rose-colored spots, particularly on the neck and abdomen.
Other symptoms can include:
Rarely, symptoms might include confusion, diarrhea, and vomiting, but this is not normally severe.
In serious, untreated cases, the bowel can become perforated. This can lead to peritonitis, an infection of the tissue that lines the inside of the abdomen, which has been reported as fatal in between 5 and 62 percent of cases.
Another infection, paratyphoid, is caused by Salmonella enterica. It has similar symptoms to typhoid, but it is less likely to be fatal.
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The only effective treatment for typhoid is antibiotics. The most commonly used are ciprofloxacin (for non-pregnant adults) and ceftriaxone.
Other than antibiotics, it is important to rehydrate by drinking adequate water.
In more severe cases, where the bowel has become perforated, surgery may be required.
Typhoid antibiotic resistance
As with a number of other bacterial diseases, there is currently concern about the growing resistance of antibiotics to S. typhi.
This is impacting the choice of drugs available to treat typhoid. In recent years, for example, typhoid has become resistant to trimethoprim-sulfamethoxazole and ampicillin.
Ciprofloxacin, one of the key medications for typhoid, is also experiencing similar difficulties. Some studies have found Salmonella typhimurium resistance rates to be around 35 percent.
Typhoid is caused by the bacteria S. typhi and spread through food, drinks, and drinking water that are contaminated with infected fecal matter. Washing fruit and vegetables can spread it, if contaminated water is used.
Some people are asymptomatic carriers of typhoid, meaning that they harbor the bacteria but suffer no ill effects. Others continue to harbor the bacteria after their symptoms have gone. Sometimes, the disease can appear again.
People who test positive as carriers may not be allowed to work with children or older people until medical tests show that they are clear.
Countries with less access to clean water and washing facilities typically have a higher number of typhoid cases.
If traveling to an area where typhoid is prevalent, vaccination is recommended.
Before traveling to a high-risk area, getting vaccinated against typhoid fever is recommended.
This can be achieved by oral medication or a one-off injection:
- Oral: a live, attenuated vaccine. Consists of 4 tablets, one to be taken every second day, the last of which is taken 1 week before travel.
- Shot, an inactivated vaccine, administered 2 weeks before travel.
Vaccines are not 100 percent effective and caution should still be exercised when eating and drinking.
Vaccination should not be started if the individual is currently ill or if they are under 6 years of age. Anyone with HIV should not take the live, oral dose.
The vaccine may have adverse effects. One in 100 people will experience a fever. After the oral vaccine, there may be gastrointestinal problems, nausea, and headache. However, severe side effects are rare with either vaccine.
There are two types of typhoid vaccine available, but a more powerful vaccine is still needed. The live, oral version of the vaccine is the strongest of the two. After 3 years, it still protects individuals from infection 73 percent of the time. However, this vaccine has more side effects.
The current vaccines are not always effective, and because typhoid is so prevalent in poorer countries, more research needs to be done to find better ways of preventing its spread.
Even when the symptoms of typhoid have passed, it is still possible to be carrying the bacteria.
This makes it hard to stamp out the disease, because carriers whose symptoms have finished may be less careful when washing food or interacting with others.
People traveling in Africa, South America, and Asia, and India in particular, should be vigilant.
Typhoid is spread by contact and ingestion of infected human feces. This can happen through an infected water source or when handling food.
The following are some general rules to follow when traveling to help minimize the chance of typhoid infection:
- Drink bottled water, preferably carbonated.
- If bottled water cannot be sourced, ensure water is heated on a rolling boil for at least one minute before consuming.
- Be wary of eating anything that has been handled by someone else.
- Avoid eating at street food stands, and only eat food that is still hot.
- Do not have ice in drinks.
- Avoid raw fruit and vegetables, peel fruit yourself, and do not eat the peel.
Written by Tim Newman