Detection of Leishmania and Trypanosoma DNA in Field-Caught Sand Flies from Endemic and Non-Endemic Areas of Leishmaniasis in Southern Thailand

Abstract

Phlebotomine sand flies are tiny, hairy, blood-sucking nematoceran insects that feed on a wide range of hosts. They are known as a principal vector of parasites, responsible for human and animal leishmaniasis worldwide. In Thailand, human autochthonous leishmaniasis and trypanosomiasis have been reported. However, information on the vectors for Leishmania and Trypanosoma in the country is still limited. Therefore, this study aims to detect Leishmania and Trypanosoma DNA in field-caught sand flies from endemic areas (Songkhla and Phatthalung Provinces) and non-endemic area (Chumphon Province) of leishmaniasis. A total of 439 sand flies (220 females and 219 males) were collected. Head and genitalia dissection of female sandflies were done for morphology identification, and the remaining parts of those sand flies were then used for the detection of Leishmania and Trypanosoma parasites. The DNA was extracted from individual female sand flies. Polymerase chain reaction (PCR) anneal, specific to the ITS1 and SSU rRNA gene regions, was used to detect Leishmania and Trypanosoma DNA, respectively. The positive PCR products were cloned and sequenced. The results showed that the female sand fly species in this study consisted of Sergentomyia khawi (35.9%); Se. anodontis (23.6%); Phlebotomus betisi (18.6%); Ph. kiangsuensis (9.5%); Ph. asperulus (6.4%); Se. barraudi (2.3%); 0.9% of each Se. indica, Ph. stantoni, and Ph. major major; and 0.5% of each Se. sylvatica and Ph. mascomai. The PCR and sequence analysis were able to detect Leishmania and Trypanosoma DNA in sand fly samples, which were identified as L. martiniquensis, 1/220 (0.45%) in Se. khawi, 3/220 (1.36%) of T. noyesi in Se. anodontis, and Ph. asperulus. Fourteen (6.36%) of the unidentified trypanosome species in Se. khawi, Se. indica, Se. anodontis, Ph. asperulus, and Ph. betisi were found in all of the areas of this study. Interestingly, we found a 1/220 (0.45%) co-infection sample of L. martiniquensis and Trypanosoma in Se. khawi from Songkhla Province. These data indicate that several species of sand flies might be potential vectors of Leishmania and Trypanosoma parasites in southern Thailand. However, more extensive study for potential vectors using a larger number of sand flies should be conducted to prove whether these sand flies can be natural vectors of leishmaniasis and trypanosomiasis in both humans and animals. In addition, our study could be useful for the future study of infection prevention, including effective vector control for leishmaniasis and trypanosomiasis in Thailand.

Identification of trypanosomatids and blood feeding preferences of phlebotomine sand fly species common in Sicily, Southern Italy

“…In particular, Trypanosoma platydactyli was described in S. minuta [42], and the infection by a Trypanosoma belonging to Trypanosoma theileri group with very high homology to other trypanosomes detected in European cervids was recently reported in Phlebotomus perfiliewi [43]. In the Mediterranean area, Trypanosoma nabiasi, a rabbit trypanosome, and its co-infection with L. infantum was found in P. perniciosus female sand flies caught in the context of human leishmaniosis outbreak in Madrid [44], and natural infection of sand flies by trypanosomes of lizards, amphibians, birds and rodents has been already reported mainly from the American continent and Asia [45][46][47][48]. Despite Trypanosoma spp.…”

Sand fly identification and screening for Leishmania spp. in six provinces of Thailand

“…Based on the morphological identification of female specimens, S. iyengari was the predominant species in several of the provinces investigated in this study, especially Chantaburi, Songkhla and Ubon Ratchathani provinces. The results of previous studies suggested that the species richness of sand flies in Thailand varied greatly among different provinces or habitats [ 19 , 32 – 36 ], possibly indicating that sand fly richness in Thailand might exhibit an area-specific distribution. These results indicated the need to investigate sand fly richness in several regions and habitats in order to obtain reliable information on sand fly species richness in Thailand.…”

“…These negative results suggest that more studies involving more traps per area need to be conducted with the aim to collect a large number of sand flies for more comprehensive investigation. In a previous study, sand flies collected in a leishmaniasis-free area of Thailand also exhibited negative results for Leishmania infection, whereas in a leishmaniasis-positive area, a low prevalence (0.45%) of Leishmania was detected [ 19 ]. In the future, an investigation of larger sand fly populations from several provinces and a variety of locations using massive molecular screening needs to be performed and possible reservoir hosts should be investigated in those areas; such studies will provide additional information on leishmaniasis transmission in Thailand.…”

“…Sergentomyia gemmea is the predominant species in Thailand and is considered to be a potential vector of L. orientalis [ 18 ]. However, there are some reports of the detection of the DNA of Leishmania parasites in sand flies, including L. martiniquensis DNA in S. gemmea , S. barraudi and S. khawi [ 15 , 18 , 19 ] as well as in black rats ( Rattus rattus ) [ 15 ]. Moreover, L. orientalis DNA was detected in S. iyengari [ 20 ].…”

Trypanosoma (Herpetosoma) diversity in rodents and lagomorphs of New Mexico with a focus on epizootological aspects of infection in Southern Plains woodrats (Neotoma micropus)

“…The 18S rRNA gene was chosen because previous analyses have demonstrated that this marker is adequate for phylogenetic differentiation of Trypanosoma species [ 40 ]. Multiple studies have used these primers to amplify Trypanosoma DNA from clades across the Trypanosoma phylogeny associated with mammals, sauropsids, amphibians, and fish [ 39 , 41 – 44 ]. A study by Hodo et al [ 45 ] was also able to amplify DNA from the related trypanosomatid genus Blastocrithidia in the blood of bats with these 18S rRNA primers.…”