Typhoid fever is an infection caused by a bacterium called Salmonella typhi. It is acquired by faecal-oral spread (when people don’t wash their hands properly after going to the toilet and then handle food or drinks), or via faecal contamination of food and water. Most cases of typhoid fever in Australia occur in travellers returning from developing countries.
Typhoid fever is different from salmonellosis (salmonella poisoning) which is caused by non-typhoidal salmonella bacteria.
Typhoid fever symptoms
The symptoms include a high fever (39°C to 40°C), which can last several days, plus headache, fatigue, muscle pains and constipation or diarrhoea. There is an incubation period (before symptoms develop) of one to 3 weeks. The diagnosis of this disease depends on finding Salmonella typhi in blood or stool specimens.
Salmonella typhi can continue to be excreted in the stools of some people after they have recovered from typhoid. These people are called carriers and can infect others.
The severity of typhoid fever varies; some people become extremely ill with widespread infection and other complications. Most people in developed countries recover with treatment, but without treatment the fatality rate can reach as high as 20 per cent.
The risk of infection is increased in areas where many people are carriers and where there is poor hygiene. For travellers, eating out in rural areas or living rough make faecal-oral transmission of any infectious disease more likely.
Preventing typhoid fever
There are 2 routes of administering typhoid vaccine: by injection or by mouth (oral).
A 3-dose oral vaccine is available in Australia for use in people 6 years of age and older; the length of time it provides protection is not well defined, but booster doses are recommended every 3 years.
There are 2 injectable vaccines available in Australia and both provide protection for 3 years. There is also a combination injectable vaccine that includes both typhoid and hepatitis A.
Typhoid vaccination should be given to people over 2 years of age who are travelling to countries where the risk of typhoid fever is high, especially those who will be exposed to poor hygiene and unsafe drinking water, those staying in rural areas, and travellers intending to stay longer than a month.
Treatment of typhoid fever is with vigilant fluid replacement and adequate nutrition, as well as antibiotics. In recent years, Salmonella typhi has developed resistance to many antibiotics, so testing is required to check that the antibiotic prescribed will be effective.