Seroprevalence of Trypanosoma evansi in cattle and analysis of associated climatic risk factors in Mizoram, India

Abstract

Surra, a haemoprotozoan parasitic disease even in subclinical form poses a challenge in terms of diagnosis and management to animal health practitioners and policy makers as well; eventually imparting financial loss to the livestock holders. A systematic study was designed to assess the seroprevalence of surra in cattle and associated climatic risk factors, by collecting 480 serum samples across the eight districts of Mizoram during 2017-2019. The apparent and true seroprevalence detected by card agglutination test was 37.08% (CI at 95%: 32.88-41.49) and 36.59% (CI at 95%: 32.4-40.99) whereas by recombinant Variable Surface Glycoprotein based indirect ELISA was 41.88% (CI at 95%: 37.5-46.3) and 40.35% (CI at 95%: 36.02-44.76) respectively. Climate parameters which influence vector population were extracted from their respective database and were correlated with seroprevalence data. Linear discriminant analysis revealed that air temperature, relative humidity and diurnal temperature range, leaf area index and soil moisture as significant risk factors discriminating seropositive and seronegative data sets classified by indirect ELISA. This study is the first report on seroprevalence of surra in cattle of Mizoram and the situation demands deployment of intervention strategies in order to assess the endemicity of the disease and thereby preventing the economic losses.

Keywords: CATT; Climate parameters; ELISA; Mizoram; Trypanosoma evansi.

Fig. 1

Map showing the point (village) of sample collection and district wise seroprevalence (%) of surra detected by iELISA across the eight districts of Mizoram