Melioidosis in Mauritius

Emerging Infectious Diseases,  Jan, 2005  by Mohammad Iqbal Issack,  Chundr Dutt Bundhun,  Hemraj Gokhool

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An association between rainfall and melioidosis has long been recognized; most cases in Thailand (9) and northern Australia (10) occur during the wet season. The increased number of cases noted during the rainy season may be caused by the movement of B. pseudomallei from deeper layers toward the surface when dry topsoil is moistened by rainfall (2).

In Mauritius, the rainy season is December to March. In January 2004, 196 mm rainfall was recorded in Port-Louis, which is 37% higher than the 1971 2000 mean rainfall for the region during this month. January 2004 was the sixth wettest January of the past 30 years in Port-Louis. Similarly above-average rainfall was recorded throughout the island in 2004.

Recent reviews have suggested a predominant role for percutaneous B. pseudomallei infection in the pathogenesis of melioidosis (11). Studies carried out in regions where melioidosis is endemic have shown that exposure to wet soil and water are associated with increased risk for disease (9). The feet of our patient were regularly exposed to wet soil during rainy periods.

In melioidosis-endemic areas, although a large percentage of the population has been exposed to B. pseudomallei, as determined by seroprevalence studies, only a few develop melioidosis (12). Most cases occur in patients with underlying illnesses, such as diabetes mellitus, renal disease, and alcoholism (9,10) or in those who are immunosuppressed (1). Our patient had SEE and was on immunosuppressive drugs. Septicemic melioidosis has been reported in patients who have SLE (13).

This first case of melioidosis in Mauritius occurred in an immunosuppressed patient who had a history of prolonged and regular exposure to mud during a year when rainfall was higher than average. This combination of 3 risk factors does not occur regularly, and it is possible that few additional cases will be recorded in Mauritius in the future. However, clinicians and laboratory staff must remain aware of this disease, particularly because in a non-communicable disease survey carried out in 1998, almost 20% of the Mauritian population >20 years of age were found to have type 2 diabetes mellitus (14), the most common predisposing condition for melioidosis (1). Determining the distribution of B. pseudomallei in soil in Mauritius by conducting environmental investigations will also be useful.

Acknowledgments

We thank the director of the meteorologic services in Mauritius for providing rainfall data.

References

(1.) White NJ. Melioidosis. Lancet. 2003;361: 1715-22.

(2.) Inglis TJJ, Mee BJ, Chang BJ. The environmental microbiology of melioidosis. Reviews in Medical Microbiology. 2001 ;12:13-20.

(3.) Jesudason MV, Anbarasu A. John TJ. Septicaemic melioidosis in a tertiary care hospital in south India. Indian J Med Res. 2003;117:119-21.

(4.) Miralles IS, Maciel Mdo C. Angelo MR, Gondini MM, Frota LH, dos Reis CM, et al. Burkholderia pseudomallei: a case of a human infection in Ceara. Brazil. Rev Inst Med Trop Sao Paulo. 2004;46:51-4.