What is typhoid?

Typhoid is a bacterial infection that can lead to a high fever, diarrhea, and vomiting. It can be fatal. It is caused by the bacteria Salmonella typhi.

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.

 If typhoid is caught early, it can be successfully treated with antibiotics; if it is not treated, typhoid can be fatal.

The bacterium lives in the intestines and bloodstream of humans. It spreads between individuals by direct contact with the faeces of an infected person.

No animals carry this disease, so transmission is always human to human.

If untreated, around 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 .

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.

How is typhoid caused?

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 .

Symptoms

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:

• weakness
• abdominal pain
• constipation
• headaches

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.

Diagnosis : Widal test

Prevention

 Countries with less access to clean water and washing facilities typically have a higher number of typhoid cases.

Vaccination:

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. 1 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 percentof 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.

Eliminating typhoid

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.

Remedies

Avoiding infection

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.

Recent research on typhoid.

A study of typhoid fever in five Asian countries: disease burden and implications for controls

Objective

To inform policy-makers about introduction of preventive interventions against typhoid, including vaccination.

Methods

A population-based prospective surveillance design was used. Study sites where typhoid was considered a problem by local authorities were established in China, India, Indonesia, Pakistan and Viet Nam. Standardized clinical, laboratory, and surveillance methods were used to investigate cases of fever of ≥ 3 days’ duration for a one-year period. A total of 441 435 persons were under surveillance, 159 856 of whom were aged 5–15 years.

Reference link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2647431/

Estimating Typhoid Fever Risk Associated with Lack of Access to Safe Water

Abstract

Background. Unsafe water is a well-known risk for typhoid fever, but a pooled estimate of the population-level risk of typhoid fever resulting from exposure to unsafe water has not been quantified. An accurate estimation of the risk from unsafe water will be useful in demarcating high-risk populations, modeling typhoid disease burden, and targeting prevention and control activities. Methods. We conducted a systematic literature review and meta-analysis of observational studies that measured the risk of typhoid fever associated with drinking unimproved water as per WHO-UNICEF’s definition or drinking microbiologically unsafe water. The mean value for the pooled odds ratio from case-control studies was calculated using a random effects model. In addition to unimproved water and unsafe water, we also listed categories of other risk factors from the selected studies. 

Reference link: https://www.hindawi.com/journals/jeph/2018/9589208/

TYPHOID FEVER NEWS AND RESEARCH

Reference link: https://www.news-medical.net/?tag=/Typhoid-Fever

Researchers find answers to growing typhoid problem in the Pacific

University of Otago researchers have been key partners in a study which has found poor sanitation facilities appear to be a major source of Salmonella Typhi, the cause of typhoid fever, in Fiji.

Reference link: https://medicalxpress.com/news/2018-06-typhoid-problem-pacific.html