Typhoid is potentially fatal infectious disease caused by bacterium Salmonella typhi (S. typhi). The name of the illness is derived from the Greek word ‘tuphos’, meaning stupor.

Although typhoid fever is now rare in most industrialized countries, it remains a serious health problem in much of the developing world. The World Health Organization estimates that about 16 million cases of typhoid fever occur annually in the world causing more than 600, 000 deaths.

Humans are the sole reservoir of S. typhi infection as well as the only natural host. Typhoid is transmitted by food or water that has been contaminated by effected individuals, a patient in convalescence, or individuals who harbour the typhoid bacteria.

Typhoid fever remains endemic in most of the less-developed areas of the world, where poor conditions of sanitation and food hygiene prevail.

An important property of S. typhi is its ability to survive in the environment, such as in snow, water and food. In some instances, this survival may be as long as several months. The hardy nature of the organism has permitted it to cause epidemics that are unexpected because no apparent recent cause for the contamination was found.

Symptoms of the disease vary from case to case but often include intermittent fever, headache, tiredness and weakness, changes in behavior, and abdominal discomfort with constipation in the early stages of the disease followed by the diarrhoea later.

The most severe complications of typhoid are intestinal bleeding and perforation.

Intestinal bleeding occurs in about 5% of typhoid cases. It occurs during 2-3 weeks after infection with sudden deterioration developing malaise, fall in blood pressure, fall in temperature and increased pulse rate.

Perforation occurs in about 4-5% of typhoid cases wherein ulcerated intestine perforates and the gut content leaks into the abdominal cavity causing infection.

Faecal matter is the most common contaminant. Others include saliva, vomitus or other body fluids. Human hands or files may also spread the contamination.

Provided early and appropriate antibiotic treatment is given, the evolution of the disease is usually favourable, although a long period of convalescence is required. Complications are frequent and serious, the most common being intestinal perforation which occurs after about 2 weeks if the disease is left untreated.

In untreated cases the mortality rate is as high as 20%. Even with adequate treatment the level of mortality still remains significant (1%). Moreover, in 3 to 5% of cases the patient remains a chronic carrier, despite antibiotic therapy.

A major and constantly rising concern in the treatment of typhoid is the emergence of a MultiDrug Resistant S. typhi(MDRST) which is making treatment increasingly difficult.

In countries with good sanitation, typhoid is mainly transmitted when chronic carriers contaminate food through a breakdown in proper practices of personal and food hygiene. In addition, those in regular contact with chronic carriers are also at increased risk of infection.

By far the most at risk group are travelers from developed countries going to high risk areas estimated to be approximately 40 million travelers in 1994 and growing by 4-5 every year.

In recent years it has become recognised that microbiology technicians in laboratories, especially clinical laboratories constitute a high-risk group for the development of typhoid fever.

Typhoid can be prevented by taking preventive measures like the provision of adequate sanitation with effective sewage disposal, a clean and safe water supply, public health regulations to prevent the contamination of food and drink, effective public health education and personal hygiene.

The other method for prevention is through vaccination.

People who should go in for vaccination against typhoid are inhabitants of areas in developing countries where typhoid is endemic, international travelers, clinical microbiology laboratory workers, household contacts of known S. typhi carriers.

With the new V_i capsular polysaccharide vaccines available in the markets, a single dose of the vaccine offers protection for up to 3 years. The currently available vaccines are nearly 100% effective and provide almost complete protection.

Clinical studies have shown the vaccines are well tolerated and reported symptoms are of mild intensity and transient.

Hepatitis A shares the same modes of transmission as typhoid (mainly through contaminated food and water). Therefore both diseases are generally seen in the same sections of the world and affecting similar groups of people. Therefore it is advisable to give people who are at high risk to typhoid protection against both diseases.

SmithKline Beecham’s proprietary Hepatitis A vaccine can be administered concomitantly with the SmithKline Beecham typhoid vaccine, making it simpler to protect against both diseases.

For more information, contact your health care centres.