Taxonomical insights and ecology of sandfly (Diptera, Psychodidae) species in six provinces of Northern Vietnam.

Sinh Nam Vu,Viet Hoang Nguyen,Duc Anh Dang,Cong Tu Tran,Ngọc Anh Hoàng,Anne-Laure Bañuls,Cécile Cassan,Jorian Prudhomme,Thi Yen Nguyen,Nil Rahola,Nhu Duong Tran,Thi Lieu Vu,Hai Son Tran,Khanh Phuong Ngo,Jérôme Depaquit,Vu Phong Tran

doi:10.1051/parasite/2021080

Abstract

We studied sandfly (Diptera: Psychodidae) populations in six provinces of Vietnam. This work explores the diversity of sandfly species according to the province, as well as environment, and updated information on public health since leishmaniasis cases were reported in two provinces. Sandflies were collected using 428 CDC light traps from May 30 to October 13, 2016 and identified based on the morphology of the cibarium, pharynx and/or male genitalia or female spermathecae. A total of 2585 sandflies belonging to five genera and 13 identified species were collected. The main species were: the Sergentomyia barraudi group (12.53%), Se. sylvatica (9.63%) and Phlebotomus stantoni (3.95%). In all, 294 Sergentomyia specimens classified as Se. sp2 and Se. sp3 and a heterogeneous group, herein called Se. und_sp., showed unknown morphological characteristics requiring further studies. We provide detailed comments about morphological description and taxonomical identification in order to help standardization of sandfly classification in Southeast Asia. We observed differentiation according to the provinces in terms of density and species richness, with Lang Son having the highest density and Ninh Binh having the highest species richness. The majority of specimens were collected in rock caves and outdoors, suggesting mainly cavernicolous and exophilic characters of sandfly species in Northern Vietnam. However, specimens were also collected in intra- and peri-domiciliary sites. It is worth noting that Ph. stantoni was the main species found in dog sheds and indoors, and in particular in a leishmaniasis patient’s house.

Highlights

Sandflies are known to be vectors transmitting leishmaniases and other pathogens to humans and animals
Five of them were identified as vectors of visceral leishmaniasis, i.e. Phlebotomus (Adlerius) chinensis, Ph. (Adl.) longiductus, Ph. (Adl.) sichuanensis, Ph. (Paraphlebotomus) alexandri, and Ph. (Larroussius) smirnovi [8, 25, 50]
In Southeast Asia, the first visceral leishmaniasis case was reported in Thailand in 1996 [47] and since 16 symptomatic cases have been notified [18]

Summary

Introduction

Sandflies are known to be vectors transmitting leishmaniases and other pathogens to humans and animals. These small insects belong to the Diptera order, Psychodidae family [12, 49] and the Phlebotominae subfamily [14]. Five of them were identified as vectors of visceral leishmaniasis, i.e. Phlebotomus (Adlerius) chinensis, Ph. In Southeast Asia, the first visceral leishmaniasis case was reported in Thailand in 1996 [47] and since 16 symptomatic cases have been notified [18]. Depaquit et al recently suggested the need to reconsider the identification of this species, underlining that much remains to be done on the classification and determination of Leishmania vector species in Southeast Asia [7]

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Results

Conclusion