Abstract
Phlebotomus argentipes is the main suspected vector for leishmaniasis in Sri Lanka. Investigations on the presence of aerobic bacteria in the gut of sand flies which evidence a potential approach to control leishmaniasis transmission through a paratransgenic strategy are still not available for the local sand fly populations. Field-caught unfed female sand flies collected from three selected Medical Officer of Health (MOH) areas (Polpithigama, Maho, and Galgamuwa) in Kurunegala District, Sri Lanka from August to December 2018 were used. Prokaryotic 16S ribosomal RNA partial gene was amplified and sequenced. Morphological identification revealed the presence of only one sand fly species, P. argentipes (n = 1,969). A total of 20 organisms belonging to two phyla (Proteobactericea and Furmicutes) were detected within the gut microbial community of the studied sand fly specimens. This study documents the first-ever observation of Rhizobium sp. in the midgut of P. argentipes. The presence of Bacillus megaterium, which is considered as a nonpathogenic bacterium with potential use for paratransgenic manipulation of P. argentipes suggest that it may be used as a delivery vehicle to block the vectorial transmission of Leishmania parasites. In addition, Serratia marcescens may be used as a potential candidate to block the parasite development in sand fly vectors since it has evidenced antileishmanial activities in previous investigations. Hence, further studies are required to gain full insight into the potential use of this bacterium in the control of Leishmania parasites through paratransgenesis.
Highlights
Leishmaniasis is a vector-borne disease transmitted through female sand flies (Psychodidae: Phlebotomine), and it is caused by a unicellular protozoan parasite belonging to the genus Leishmania
Morphological identification revealed the presence of a single species, P. argentipes, which is reported to be the vector for cutaneous leishmaniasis in Sri Lanka
The present study indicated the occurrence of Staphylococcus saprophyticus, S. sciuri, S. arlettae, S. warneri, Serratia marcescens, Aeromonas caviae, Stenotrophomonas panacihumi, Bacillus licheniformis, B. sonorensis, Rhizobium sp., and B. subtilis in P. argentipes, which is comparable to some previously published studies
Summary
Leishmaniasis is a vector-borne disease transmitted through female sand flies (Psychodidae: Phlebotomine), and it is caused by a unicellular protozoan parasite belonging to the genus Leishmania. It is considered a neglected tropical disease, and at present, this disease is endemic in 102 countries [1]. Female sand flies feed on mammalian blood for egg development and maturation. As both males and females feed on plant nectar as a sugar source, they may acquire plant bacteria [2]. Previous studies have indicated that newly emerged sand flies were associated with a large amount of bacterial DNA that could be taken from the environment by feeding or transtadial passage [3]
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