FOUND in soil and water, the bacterium Burkholderia pseudomallei, which causes melioidosis, is endemic in South-east Asia, as well as north and western Australia. In the last five years, cases have also been spotted in South America.

Up to 2,000 people are infected in South-east Asia each year.

An average of 67 people caught it annually in Singapore between 1994 and 2004.

First documented here in 1920, the bacteria are found in most kinds of soil, but have not been detected on sandy beaches, said Dr Ooi Eng Eong, a research-clinician at DSO National Laboratories.

Those infected suffer from abscesses, pneumonia or blood poisoning. About 18 per cent of those infected die.

This is down from 59 per cent in 1990, said Associate Professor Raymond Lin, head of the National University Hospital's microbiology division at the laboratory medicine department.

To understand the disease better, the Ministry of Health made it mandatory in 1989 for laboratories to report any cases of melioidosis.

The last outbreak was seen after heavy rains in March 2004, when 11 cases were reported in the space of a week.

About 30 per cent of patients died that year. This is about twice the mortality rate attributed to the severe acute respiratory syndrome (Sars), which hit Singapore in 2003.