Abstract:
Autochthonous leishmaniasis cases in Thailand are increasing dramatically, the disease is caused by two major of Leishmania species; L. orientalis and L. martiniquensis. Leishmaniasis is transmitted to the vertebrate hosts through the bite of the infected female sand fly. Moreover, other trypanosomatid protozoa have also been reported in this insect vector. In 2016, Trypanosoma sp. has been detected in sand fly from Songkhla province, where the leishmaniasis case has been reported. The aims of this study are to investigate the potential vectors of trypanosomatids in this area using morphological and molecular identification based on the Cytb gene. The parasites were screened by using ITS1 and SSU rRNA-PCR based methods. Five species of female sand flies were found in this study. Among 349 samples tested, DNA of trypanosomatids was detected in Sergentomyia (Parrotomyia) barraudi (0.9%), Se. (Grassomyia) indica (1.4%), Se. khawi (3.7%), Phlebotomus stantoni (1.1%), and non-sand fly (0.3%). Based on retrieved SSU rRNA sequences, phylogenetic analysis reveals that 96.2% of the detected parasites belong to anuran trypanosomes. Twenty-three were the anuran Trypanosoma spp. of clade Frog 1, and the other two were novel species of clade Frog 2. Moreover, Leishmania infantum DNA was detected in a Ph. stantoni (3.8%) based on ITS1-PCR. Since 2008, there had never been reported the detection of L. infantum in any leishmaniasis cases from Thailand or in sand flies. Therefore, this present study demonstrates for the first time that L. infantum DNA can be detected in Ph. stantoni collected from Songkhla, Thailand.
