Typhoid and paratyphoid

Typhoid and paratyphoid (also called typhoid and paratyphoid fever) are bacterial infections of the intestinal tract and bloodstream. The bacterium responsible for typhoid is Salmonella typhi, and the one responsible for paratyphoid is Salmonella paratyphi.

These infections can occur anywhere, but they are far more common in places with unsafe water supplies and poor sanitation. About 9 million people are affected by typhoid worldwide each year. In countries with good sanitation and clean water, the infections are rare, and most cases are picked up during overseas travel.

How typhoid and paratyphoid spread#

The bacteria are carried by humans and, rarely, by domestic animals. The Salmonella typhi bacterium is carried only by humans, while no other animal carrier has been found for paratyphoid either in most settings. An infected person carries the bacteria in their feces (poo) and sometimes in their urine.

If someone with the infection does not wash their hands carefully after going to the toilet, they can spread the bacteria from their hands to surfaces and objects, which may then come into contact with food or be touched by other people. Hands can also become contaminated when changing the nappy of an infected infant.

Water sources contaminated with infected feces are another common way the infection is transmitted.

Carriers#

Without treatment, about one person in 20 who recovers from typhoid becomes a “carrier”. Despite having no symptoms, they carry bacteria in their feces and urine and can infect others for about three months (sometimes up to one year). About 2 to 5 per cent of carriers remain permanently infectious.

People who recover from paratyphoid without medical treatment can also become carriers, although this is less common.

Incubation and course of illness#

The incubation period for typhoid is usually 7 to 14 days, but ranges from 3 to 60 days. For paratyphoid, it is about 1 to 10 days.

Symptoms often begin slowly, gradually worsening over about three or four days. Untreated, the illness typically lasts about four weeks, and any complications tend to appear after about two or three weeks.

Who is most at risk#

People at highest risk of typhoid and paratyphoid include:

• people who live in or travel to areas where typhoid and paratyphoid are widespread
• young children, who are at greater risk of infection than adults
• people who return to a country of birth to visit friends or relatives
• anyone who has had close contact with an infected person

People who have been vaccinated against typhoid are at lower risk, but vaccination is not 100 per cent effective. Between 20 and 50 per cent of vaccinated people may still develop typhoid after exposure.

Symptoms#

Symptoms of typhoid range from mild to severe, can last about a month without treatment, and may include:

• fatigue or tiredness
• malaise (a general feeling of being unwell)
• sore throat and a persistent cough
• headache
• a slower than usual heart rate
• sweating
• nausea (feeling sick) and abdominal pains
• changes in bowel habits, such as constipation or diarrhea
• lack of appetite and weight loss
• a reddened skin rash on the chest and stomach
• mental changes such as confusion
• blood poisoning (septicemia)
• enlarged spleen (splenomegaly) and enlarged liver (hepatomegaly)

Compared with typhoid, paratyphoid generally causes similar but milder symptoms, with a faster recovery and fewer complications.

Complications#

The serious and potentially fatal complications of typhoid and paratyphoid include:

• intestinal hemorrhage – bleeding from the intestine (signs include a sudden drop in blood pressure and blood in the feces)
• intestinal perforation – a hole in the intestine that allows intestinal contents and blood to leak into the abdominal cavity
• infection of other organs, such as the lungs (pneumonia), kidneys, bladder or spine
• meningitis – inflammation of the membranes around the brain and spinal cord
• inflammation of other organs, such as the heart or pancreas

Diagnosis#

Diagnosis of typhoid or paratyphoid fever may include:

• a physical examination
• a review of your medical and travel history
• blood, stool (feces) and urine tests
• a bone marrow test

Treatment#

Without prompt medical treatment, typhoid and paratyphoid fevers can be fatal. Treatment options may include:

• hospitalization – some people need specialized, supportive care for a few days
• antibiotics – to kill the bacteria, reduce the risk of complications and speed recovery
• plenty of fluids – to counter the dehydration caused by diarrhea and fever

If you have had typhoid or paratyphoid, you remain infectious until all your symptoms have cleared and you have been well for at least 24 hours. In the meantime, to avoid infecting others:

• do not go to work, school or childcare
• do not handle or prepare food for other people in your household
• avoid sharing towels, food utensils or food with others
• wash your hands thoroughly with soap and water after using the toilet

Speak with your doctor for more detailed instructions. Children with typhoid or paratyphoid should be kept away from school and childcare until cleared to return by a health authority.

About 5 to 10 per cent of people relapse (become sick again), usually two to three weeks after recovering from typhoid. Speak with your doctor if you develop any symptoms again.

Preventing typhoid and paratyphoid when travelling#

In many places, healthcare professionals are required to notify the authorities about cases of typhoid. Travelers can take a number of precautions before and during travel to reduce their risk.

Anyone travelling overseas should see their doctor or a travel health clinic to find out which vaccinations they need. Even if you think your destination is safe, keep in mind that disease outbreaks can and do happen.

Vaccination#

Several types of typhoid vaccine are available, along with a combination vaccine that also covers hepatitis A. Typhoid vaccination offers good protection but is not 100 per cent effective: about 20 to 50 per cent of vaccinated people may still contract typhoid after exposure. There is no paratyphoid vaccine.

Vaccinations should be given at least two weeks before you travel. Protection does not last forever, so ask your doctor whether you need another dose before future travel. Vaccination is not a guarantee that you will not catch typhoid fever.

Food and water safety#

Careful attention to eating habits and personal hygiene is very important while travelling in places with unsafe water and poor sanitation. Suggestions include:

• avoid buying food from street vendors
• eat only hot foods and avoid meals served cold or at room temperature
• avoid seafood, particularly shellfish
• do not eat raw fruit or vegetables, including fresh fruit juice and salads – fruit or vegetables that you peel yourself are usually safe
• avoid raw or runny eggs
• avoid unpasteurized milk and dairy products, including ice cream
• do not have ice in your drinks
• drink bottled water, and use it to brush your teeth

Wash your hands thoroughly with soap after going to the toilet, before preparing food, and before eating. Carry a bottle of alcohol-based hand sanitiser for times when soap and clean water are not available, and keep your hands away from your face and mouth.

Key points#

• Water contaminated with infected feces is a common way the infection is transmitted.
• Without treatment, about one person in 20 who recovers from typhoid becomes a carrier.
• People who recover from paratyphoid without treatment can also become carriers, although this is less common.
• Symptoms may begin slowly, gradually worsening over about three or four days.
• People vaccinated against typhoid are at lower risk, but vaccination is not 100 per cent effective.

Where to get help#