A survey on Mycobacterium ulcerans in Mosquitoes and March flies captured from endemic areas of Northern Queensland, Australia.

Avishek Singh,Brenda Govan,William John Hannan Mcbride,Scott A Ritchie,Mark Pearson,Timothy P Stinear

doi:10.1371/journal.pntd.0006745

Avishek Singh, Brenda Govan + Show 4 more

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https://doi.org/10.1371/journal.pntd.0006745

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Abstract

Mycobacterium ulcerans is the causative agent of Buruli ulcer (BU). This nontuberculous mycobacterial infection has been reported in 34 countries worldwide. In Australia, the majority of cases of BU have been recorded in coastal Victoria and the Mossman-Daintree areas of north Queensland. Mosquitoes have been postulated as a vector of M. ulcerans in Victoria, however the specific mode of transmission of this disease is still far from being well understood. In the current study, we trapped and analysed 16,900 (allocated to 845 pools) mosquitoes and 296 March flies from the endemic areas of north Queensland to examine for the presence of M. ulcerans DNA by polymerase chain reaction. Seven of 845 pools of mosquitoes were positive on screening using the IS2404 PCR target (maximum likelihood estimate 0.4/1,000). M. ulcerans DNA was detected from one pool of mosquitoes from which all three PCR targets: IS2404, IS2606 and the ketoreductase B domain of mycolactone polyketide synthase gene were detected. None of the March fly samples were positive for the presence of M. ulcerans DNA.

Highlights

Buruli ulcer (BU), known regionally as Daintree ulcer in north Queensland, Australia or Bairnsdale ulcer in Victoria, Australia, is an emerging disease of skin and underlying tissue, with a potential to lead to permanent disability, if treatment is inadequate or delayed
Studies conducted in endemic areas of Africa suggest that conducting farming activities close to rivers [8] and swimming in rivers located in endemic areas [9] are risk factors for exposure to M. ulcerans
Total mosquitoes captured from region-1, region-2 and region-3 were 7880, 5100, and 3920, respectively

Summary

Introduction

Buruli ulcer (BU), known regionally as Daintree ulcer in north Queensland, Australia or Bairnsdale ulcer in Victoria, Australia, is an emerging disease of skin and underlying tissue, with a potential to lead to permanent disability, if treatment is inadequate or delayed. The outbreaks of BU have been consistently linked with wetland or coastal regions [2] Environmental samples such as water, aquatic plants, soil at endemic areas has been found PCRpositive for M. ulcerans DNA [3, 4]. A study conducted by Marsollier and his colleagues provided evidence of the presence of M. ulcerans DNA in the salivary gland of wild caught Naucoridae (aquatic bug) They successfully isolated the pathogen by culture from the salivary glands of aquatic bugs and suggested aquatic insects as having an important ecological niche in the maintenance of the organism in the environment. Studies conducted in endemic areas of Africa suggest that conducting farming activities close to rivers [8] and swimming in rivers located in endemic areas [9] are risk factors for exposure to M. ulcerans

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