Species identification and phylogenetic analysis of Leishmania isolated from patients, vectors and hares in the Xinjiang Autonomous Region, The People's Republic of China.

Yun-Fu Chen,Na Wu,Li-Fu Liao,Geoff Hide,Jiang-Mei Gao,Zhao-Rong Lun,De-Hua Lai,Peng Zhang,Yan-Zi Wen,Gabriele Schönian

doi:10.1371/journal.pntd.0010055

Abstract

Visceral leishmaniasis (VL) has been declared as one of the six major tropical diseases by the World Health Organization. This disease has been successfully controlled in China, except for some areas in the western region, such as the Xinjiang Autonomous Region, where both anthroponotic VL (AVL) and desert type zoonotic VL (DT-ZVL) remain endemic with sporadic epidemics. Here, an eleven-year survey (2004-2014) of Leishmania species, encompassing both VL types isolated from patients, sand-fly vectors and Tarim hares (Lepus yarkandensis) from the Xinjiang Autonomous Region was conducted, with a special emphasis on the hares as a potential reservoir animal for DT-ZVL. Key diagnostic genes, ITS1, hsp70 and nagt (encoding N-acetylglucosamine-1-phosphate transferase) were used for phylogenetic analyses, placing all Xinjiang isolates into one clade of the L. donovani complex. Unexpectedly, AVL isolates were found to be closely related to L. infantum, while DT-ZVL isolates were closer to L. donovani. Unrooted parsimony networks of haplotypes for these isolates also revealed their relationship. The above analyses of the DT-ZVL isolates suggested their geographic isolation and independent evolution. The sequence identity of isolates from patients, vectors and the Tarim hares in a single DT-ZVL site provides strong evidence in support of this species as an animal reservoir.

Highlights

Visceral leishmaniasis (VL), caused by species of the Leishmania donovani complex, is a potentially fatal disease if not treated [1]
What is the animal reservoir for desert type zoonotic VL (DT-ZVL), as sand flies get infected in areas free of patient or infected dogs? To address this question, an eleven-year survey (2004–2014) in Xinjiang for Leishmania species was carried out
We found that VLs in Xinjiang are contributed to Leishmania donovani complex, and Tarim hares is likely the reservoir animal for DT-ZVL

Summary

Introduction

Visceral leishmaniasis (VL), caused by species of the Leishmania donovani complex, is a potentially fatal disease if not treated [1]. The control programs have successfully eliminated VL in the northeastern plain, but not in the west and northwest regions, where this disease has persisted as three different types: mountain type zoonotic VL (MT-ZVL), anthroponotic VL (AVL) and desert type zoonotic VL (DT-ZVL) [2]. This study considers the causative agents of AVL and DT-ZVL from the Xinjiang Autonomous Region in the northwest of China. Visceral leishmaniasis (VL) has been declared as one of the six major tropical diseases by the World Health Organization. This disease has been successfully controlled in China, except for some areas in the western region, such as the Xinjiang Autonomous Region, where both anthroponotic VL (AVL) and desert type zoonotic VL (DT-ZVL) remain endemic with sporadic epidemics

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Conclusion