Chinius barbazanin. sp. de Thailande (Diptera : Psychodidae)

Phlebotomine sand flies (Diptera, Psychodidae) from Pha Tong cave, Northern Thailand with a description of two new species and taxonomical thoughts about Phlebotomus stantoni

BACKGROUND

In South-East Asia, Thailand is the country with the highest number of human autochthonous cases of leishmaniases mostly due to Leishmania martiniquensis. Their transmission remains unresolved to date even though sand flies are known vectors of leishmaniases. As such, we focused a study on the sand fly fauna of a cave in Thailand to explore the biodiversity of potential Leishmania vectors.

MAIN RESULTS

We carried out an inventory in Pha Tong cave. We caught and identified 570 Phlebotomine sand flies (452 females and 118 males) and identified 14 species belonging to the genera Phlebotomus, Idiophlebotomus, Chinius, Sergentomyia and Grassomyia. Among these 14 species, two could not be related to known sand fly species. Herein, we propose the description of two new sand fly species, previously unknown to science. The first new species, Phlebotomus shadenae n. sp. is a sand fly of the subgenus Anaphlebotomus. It is morphologically close to Ph. stantoni, a species widely distributed throughout Southeast Asia. However, it differs by the length of the genital filaments in males or by the length of the ducts of the spermathecae in females as well as the high divergence of cytochrome b sequences. Additionally, we revised the systematics of the subgenus Anaphlebotomus and reinstated, by examination of its holotype, the validity of Ph. maynei, an Indian wrongly considered as a synonym of Ph. stantoni in the past. The second new species, Sergentomyia maiae n. sp., differs from a species in the same group, Se. barraudi, by an original cibarial double row of vertical teeth as well as by molecular data.

CONCLUSIONS

We propose the description of two new sand fly species for Science with morphological and molecular evidence. Ph. shadenae n. sp. was also found to be distributed in the south of Thailand and in Laos. Future studies need to determine whether these two species can play a role as vectors of Leishmania parasites, Trypanosomatids or Phlebovirus. Most of the species caught in the present study are strictly cavernicolous except Grassomyia sp. and a few Sergentomyia.

Species diversity of phlebotomine sand flies and sympatric occurrence of Leishmania (Mundinia) martiniquensis, Leishmania (Leishmania) donovani complex, and Trypanosoma spp. in the visceral leishmaniasis focus of southern Thailand

Autochthonous leishmaniasis in Thailand has recently been a public health concern due to an increasing number of new clinical cases. Most indigenous cases were diagnosed with Leishmania (Mundinia) martiniquensis, and Leishmania (Mundinia) orientalis. However, some doubts regarding vector misidentification have arisen and need to be elucidated. Accordingly, we aimed to assess the species composition of sand flies and determine the molecular prevalence of trypanosomatids in the transmission area of leishmaniasis in southern Thailand. In the present study, a total of 569 sand flies were caught from the vicinity of a visceral leishmaniasis patient's house in Na Thawi District, Songkhla Province. Of these, 229 parous and gravid females consisted of Sergentomyia khawi, Se. barraudi, Phlebotomus stantoni, Grassomyia indica, and Se. hivernus, accounting for 31.4%, 30.6%, 29.7%, 7.9%, and 0.4%, respectively. However, Se. gemmea, which has previously been proposed as the most abundant species and putative vector of visceral leishmaniasis, was not found in the present study. Based on ITS1-PCR and sequence analysis, two specimens of Gr. indica and Ph. stantoni showed positive amplification of L. martiniquensis and L. donovani complex, respectively, the first one being presumed indigenous and the second one being not. Anuran Trypanosoma was also molecularly detected using SSU rRNA-PCR and ubiquitously found in sixteen specimens of four dominant sand fly species except for Se. hivernus. The obtained sequences could be phylogenetically categorized into the two major amphibian clades (An04/Frog1 and An01+An02/Frog2). The existence of the monophyletic subgroup and distinct lineage suggests them as novel Trypanosoma species. The TCS network analysis of these anuran Trypanosoma sequences also revealed high haplotype diversity (Hd = 0.925 ± 0.050), but low nucleotide diversity (π = 0.019 ± 0.009). Furthermore, the living anuran trypanosomes were microscopically demonstrated in a single specimen of Gr. indica, supporting the vectorial capacity. Importantly, our data confirmed the scarcity of Se. gemmea and also uncovered, for the first time, the co-circulation of L. martiniquensis, L. donovani complex, and suspected novel anuran Trypanosoma spp. in phlebotomine sand files, implicating their potential role as vectors of trypanosomatid parasites. Therefore, the novel data from this study would greatly facilitate the comprehension of the complexity of trypanosomatid transmission and the establishment of prevention and control measures for this neglected disease more effectively.

Phlebotomine sand flies (Diptera: Psychodidae) and sand fly-borne pathogens in the Greater Mekong Subregion: a systematic review

Phlebotomine sand flies are proven or suspected vectors of several pathogens of importance, including leishmaniasis, bartonellosis and sand fly fevers. Although sand flies have a worldwide distribution, there has been limited research published on sand flies and sand fly-borne pathogens throughout the Greater Mekong Sub-region (GMS). This review followed the PRISMA guidelines to determine the biodiversity and presence of phlebotomine sand flies and their associated pathogens in the GMS, specifically Cambodia, Thailand, the Lao People’s Democratic Republic (Laos), Malaysia and Vietnam. A total of 1472 records were identified by searching electronic databases, scanning reference lists of articles and consulting experts in the field. After screening of title and abstracts, 178 records remained and were further screened for original data (n = 34), not having regional data (n = 14), duplication of data (n = 4), records not available (n = 4) and no language translation available (n = 2). A total of 120 studies were then included for full review, with 41 studies on sand fly-related disease in humans, 33 studies on sand fly-related disease in animals and 54 entomological studies focused on sand flies (5 papers contained data on > 1 category), with a majority of the overall data from Thailand. There were relatively few studies on each country, with the exception of Thailand, and the studies applied different methods to investigate sand flies and sand fly-borne diseases, impacting the ability to conduct meaningful meta-analysis. The findings suggest that leishmaniasis in humans and the presence of sand fly vectors have been reported across several GMS countries over the past 100 years, with local transmission in humans confirmed in Thailand and Vietnam. Additionally, local Mundinia species are likely transmitted by biting midges. Findings from this study provide a framework for future investigations to determine the geographic distribution and risk profiles of leishmaniasis and other associated sand fly-borne disease throughout the GMS. It is recommended that researchers expand surveillance efforts across the GMS, with an emphasis placed on entomological surveys, syndromic and asymptomatic monitoring in both humans and animals and molecular characterization of sand flies and sand fly-borne pathogens, particularly in the understudied countries of Cambodia, Vietnam and Laos.

A new cavernicolous sand fly from Cambodia: Idiophlebotomus nicolegerae n. sp. (Diptera: Psychodidae)

Cambodia is an area considered free of leishmaniasis and consequently little is known of its' phlebotomine sand fly fauna. Only six species of sand flies have previously been recorded: Sergentomyia barraudi, Sergentomyia pertubans, Sergentomyia bailyi, Sergentomyia silvatica, Sergentomyia khawi and Grassomyia indica and none belonging to the genus Phlebotomus. During an inventory carried out in Cambodia, we caught a new species, belonging to the genus Idiophlebotomus, in a cave. We describe the new species in this paper and also report three other new species for the country: Sergentomyia anodontis, Phlebotomus stantoni and Phlebotomus kiangsuensis.

Description of Sergentomyia phadangensis n. sp. (Diptera, Psychodidae) of Thailand

Background

Since 1996, there are emerging autochthonous cases of leishmaniasis in Thailand due to Leishmania “siamensis” and to L. martiniquensis explaining a recent interest for the sand fly fauna where Sergentomyia gemmea and Se. barraudi have been considered possible vectors in the country.

Methods

Field studies were undertaken in a cave of Phitsanulok Province, Thailand. Phlebotomine sandflies have been studied morphologically and some have been processed for molecular biology (sequencing of cytB rDNA).

Results

A new species of sand fly, belonging to the genus Sergentomyia: Se. phadangensis n. sp., is described. The association of the male and female is supported by the homology of the sequences of cytochrome b rDNA.

Conclusions

The description of a new species in Thailand is of importance in view of the existence of autochthonous leishmaniases.

Towards monitoring the sandflies (Diptera: Psychodidae) of Thailand: DNA barcoding the sandflies of Wihan Cave, Uttaradit

Sandflies vary in their distributions and role in pathogen transmission. Attempts to record distributions of sandflies in Thailand have faced difficulties due to their high abundance and diversity. We aim to provide an insight into the diversity of sandflies in Thailand by (i) conducting a literature review, and (ii) DNA barcoding sandflies collected from Wihan Cave where eight morphologically characterized species were recorded. DNA barcodes generated for 193 sandflies fell into 13 distinct species clusters under four genera (Chinius, Idiophlebotomus, Phlebotomus and Sergentomyia). Five of these species could be assigned Linnaean species names unambiguously and two others corresponded to characterized morphospecies. Two species represented a complex under the name Sergentomyia barraudi while the remaining four had not been recognized before in any form. The resulting species checklist and DNA barcode library contribute to a growing set of records for sandflies which is useful for monitoring and vector control.

Description of the sandfly species Chinius samarensis n. sp. (Psychodidae; Diptera) from the Philippines

The authors have described Chinius samarensis n. sp. (Diptera; Psychodidae) from the Philippines (Island of Samar). This is the fourth known species belonging to the Asiatic genus Chinius Leng, 1987. Like the other Chinius, C. samarensis n. sp. is a cavernicolous species. The genital ducts of the male are four times shorter than the spermathecal ducts. However, the authors think that male and female belong to the same species due to their similar cytochrome b mt DNA sequences. A differential diagnosis with the other species belonging to the genus Chinius is provided.

Chinius eunicegalatiae n. sp. (Diptera; Psychodidae), a cavernicolous sandfly from Laos

A description is given of Chinius eunicegalatiae n. sp. (Diptera; Psychodidae) from Laos. This is the third known species belonging to the Asiatic genus Chinius Leng, 1987. Like C. junlianensis Leng, 1987 and C. barbazani Depaquit, Léger and Beales, 2006, C. eunicegalatiae n. sp. is a cavernicolous species. An absence of the R2 vein is shared with C. barbazani. A differential diagnosis with the two other known species of the genus is given. The main differential characters are the lengths of the genital filaments and of the spermathecal ducts.

Phlebotomus (Euphlebotomus) barguesae n. sp. from Thailand (Diptera - Psychodidae)

Background

A few studies have been carried out on the Phlebotomine sandflies from Thailand. Within the Phlebotomine sandflies, the genus Phlebotomus Rondani & Berté, 1840 contains the vectors of leishmaniases in Europe, Africa and Asia. It includes several subgenera. Among them the subgenus Euphlebotomus Theodor, 1948 contains at the present time 12 taxa. The type-species of this subgenus is P. argentipes Annandale & Brunetti, 1908, the vector of Leishmania donovani (Laveran & Mesnil, 1903) in India.

Results

A new species of sandfly, P. barguesae n. sp. is described from limestone caves in Thailand. The male-female gathering in the same species is based on ecological, morphological and molecular criteria (homology of mtDNA cytochrome c oxidase I sequences). The inclusion of P. barguesae n. sp. in the subgenus Euphlebotomus is justified on the basis of characters of the male genitalia (five spines on the style, bifurcated paramere, and no basal lobe on the coxite) and of female pharyngeal armature (two kinds of teeth). It well differenciated from another sympatric species: P. mascomai.

Conclusion

The new species described in the present study has smooth spermathecae. This original morphology opens a discussion on the heterogeneity of this subgenus.