PREVALENCE, MOLECULAR CHARACTERISATION AND THERAPEUTIC ASPECTS OF TRYPANOSOMA EVANSI INFECTION IN CATTLE
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Date
2019-07
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Dau Shri Vasudev Chandrakar Kamdhenu Vishwavidyalaya, Durg
Abstract
In India, trypanosomiasis, popularly known as “Surra” caused by T. evansi, a haemo flagellated protozoan parasite produces acute to chronic disease in a wide range of animals.
The parasite can be microscopically identified only in clinical cases, not in latent or carrier
animals. Therefore a cross-sectional study was conducted to determine the prevalence of T.
evansi infection through a multistage sampling method in the plain regions of Chhattisgarh
state during the three seasons (April 2018- January 2019). For this study, a total of 920
samples were collected from cattle of different breed, age, sex and rearing systems. An
overall prevalence of T. evansi of 4.57% (95% CI: 3.22-5.92) through microscopical
examination, 63.91% (95% CI: 60.81-67.01) through WCLA ELISA and 55.33% (95% CI:
52.12- 58.54) by IFAT was recorded during the study. There was a variation in prevalence of
T. evansi with respect to different risk factors like sector, age, sex, breed, season and district.
A significant difference in spatial distribution of T. evansi antibody was recorded among
cattle of different farms (Organised) and villages (Unorganised household rearing units) and
significant difference was also observed in temporal distribution of T. evansi antibody with
respect to different seasons by ELISA and IFAT. Through binary logistic regression
analysis, different risk association in respect to prevalence was also analysed. It was
observed that prevalence of T. evansi through microscopical examination has a higher risk
association in HF cross breed cattle during rainy season. Risk of prevalence of T. evansi
antibody as per WCLA ELISA was significantly higher during summer and rainy season and
IFAT was significantly higher among organised sectors during the summer and rainy season.
Repeat breeding cattle recorded during the survey had T. evansi antibody as per ELISA and a
significant higher Odd’s ratio was recorded with seropositivity by IFAT. Molecular detection
of six microscopically T. evansi positive cases was done by PCR at 477bp for ITS1 and
sequences submitted to NCBI were found having maximum similarity with the isolates
published from Hissar, Haryana with some mutation and additions at some positions.
Pathological effects of T. evansi in affected cattle were altered haemato-biochemical profile
which included significant anaemia accompanied by leucopenia, lymphopenia, oesinophilia,
neutrophilia, thrombocytopenia and reduced Glucose, Total Protein, Albumin, Globulin, A/G
ratio and increased BUN, AST, ALT and Creatinine. Twenty cattle naturally affected with T.
evansi were divided into two groups; group I comprising of 10 animals were treated with
Isometamidium @ 0.5 mg/kg b.wt, i/m single dose and group II comprising of 10 animals
were treated with Quinapyramine @ 4.4 mg/kg.b.wt, s/c, single dose. Animals of the both
treated groups also received supportive therapy. Animals of both the treated groups were
found microscopically negative for T. evansi on 3rd day post treatment and restored the
altered haemato-biochemical parameters during post-treatment observation period.