Nationwide serological surveillance of non-tsetse-transmitted horse trypanosomoses in Mongolia

Daiki Mizushima,Davaajav Otgonsuren,Mitsunori Kayano,Bayasgalan Mungun-Ochir,Batdorj Davaasuren,Purevdorj Baatarjargal,Banzragch Battur,Batbold Davkharbayar,Thu-Thuy Nguyen,Sandagdorj Naransatsral,Uranbileg Nyamdolgor,Batsaikhan Enkhtaivan,Gurdorj Soyolmaa,Badgar Battsetseg,Tovuu Amgalanbaatar,Noboru Inoue,Keisuke Suganuma,Myagmar Zoljargal,Punsantsogvoo Myagmarsuren,Naoki Yokoyama ,Аltanchimeg Adilbish

doi:10.1016/j.parepi.2020.e00158

Abstract

In Mongolia, horses play important roles, not only in livestock production, but also in terms of culture, tradition, and Mongolian beliefs. Although the presence of non-tsetse-transmitted horse trypanosomoses, which are caused by infections with Trypanosoma evansi (surra) and T. equiperdum (dourine), has been reported in the country, whether there is a nationwide epidemic of these infectious diseases is unknown. In the present study, a nationwide surveillance of horse trypanosomoses was performed. The sample sizes for each province, the whole country, and male and female horses were, respectively, 96, 2,400, and 316 and 306. In total, 3,641 samples of horse sera were collected by simple random sampling. The rTeGM6-4r-based ELISA, which was applied for surra against cattle and water buffalo and dourine against horse, revealed that the overall sero-prevalence of the diseases in Mongolia was 4.8%. Among them, high sero-prevalences were observed in the central provinces (5.2–11.0%, p < 0.05) of the country. The sero-prevalence was significantly higher in females than in males (6.0% and 4.0%, p < 0.05, respectively) and in non-castrated males (8.4%, p < 0.01) compared with castrated males (3.0%). These results suggested that currently, horse trypanosomoses are a nationwide endemic problem in Mongolia. Knowledge of the nationwide endemic status of non-tsetse-transmitted horse trypanosomoses in Mongolia will be useful to prevent these diseases.

Highlights

The four million horses living in the whole area of Mongolia play important roles in livestock production, and in terms of culture, tradition, and Mongolian beliefs
It has been reported that non-tsetse-transmitted horse trypanosomoses, namely surra and dourine, were prevalent in Mongolia and the neighboring countries (Claes et al, 2005a; Clausen et al, 2003; Davaasuren et al, 2017; Luckins, 1988; Lun et al, 1992; Organisation for Animal Health (OIE), 2013a; Suganuma et al, 2016)
T. equiperdum is associated with the characteristic features of the parasite, which primarily parasitizes in the genital mucosa of equids and rarely parasitizes in blood, dissimilar to T. evansi (Brun et al, 1998)

Summary

Introduction

The four million horses living in the whole area of Mongolia play important roles in livestock production (including transportation, milk, and meat production), and in terms of culture, tradition, and Mongolian beliefs. It has been reported that non-tsetse-transmitted horse trypanosomoses, namely surra and dourine, were prevalent in Mongolia and the neighboring countries (Claes et al, 2005a; Clausen et al, 2003; Davaasuren et al, 2017; Luckins, 1988; Lun et al, 1992; OIE, 2013a; Suganuma et al, 2016) These reports raised concerns about the risk of these diseases spreading and suggested that their spread would cause huge economic losses in terms of horse production. T. equiperdum is associated with the characteristic features of the parasite, which primarily parasitizes in the genital mucosa of equids and rarely parasitizes in blood, dissimilar to T. evansi (Brun et al, 1998) This disease is characterized by genital lesions, cutaneous plaques, and nervous signs, which are similar to those of surra (Claes et al, 2005b; Gizaw et al, 2017)

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Conclusion