Early detection of Trypanosoma evansi infection and monitoring of antibody levels by ELISA following treatment

Abstract

In present communication, we report an outbreak of Trypanosoma evansi in equine herd n = 30 (horse and mules) which, were reared in fly proof stables as well as in open paddock maintained under semi-intensive system of management, and its effective control using trypanocidal drug. The infection was monitored by antibody ELISA up to 180 days post-treatment (PT). A total of 8 out of 14 equines (57.14 %) which were maintained only in open paddocks were found positive with T. evansi infection parasitologically. The infected animals were treated with quinapyramine methyl sulphate and chloride combination administered at the prescribed dose rate on 3rd day of screening. The parasite could not be detected from any treated animals from day-3 PT up to 6 month. Further, we also could not observe relapse of infection, neither in treated group nor in equine herd maintained at the farm. Sero-conversion was observed in all eight animals by 10th day of screening, indicating that immune response was due to recent infection as the animals became chronologically positive. The antibody titre reached at the peak by 10-14th day in all infected animals, and started declining by 17th day of screening, further reached to near cut off level by 180 days. Since, antibodies persisted up to 6 month PT and antibody detection assays are not able to differentiate between current and past infections in treated cases. The detection of circulating antigen assay and parasitological techniques in combination may be performed for effective diagnosis and management of T. evansi infection.

Biocompatibility and Targeting Efficiency of Encapsulated Quinapyramine Sulfate-Loaded Chitosan-Mannitol Nanoparticles in a Rabbit Model of Surra

“…Once the animal is infected, T. evansi antibodies persist in the animal body even after treatment or recovery. In our previous study in equines, antibodies persisted up to 6 month posttreatment (12,21); therefore, this finding should be correlated with clinical signs and parasitological techniques to differentiate between current and treated cases (12). Symptoms of the disease were relieved after 14 days of treatment of the animals, and clearance of the parasites was observed from day 3 to 42 in all rabbits.…”

“…The parasites were visible in the wet blood smears from day 3 to day 5 followed by intermittent parasitemia. Inconsistent parasitemia is characteristic of this disease in rabbits and other animals (10,12). The antibody levels against T. evansi before the treatment were measured.…”

“…Measurement of antibodies against T. evansi. The T. evansi-specific antibodies in infected and uninfected rabbits were estimated by enzyme-linked immunosorbent assay (ELISA) as previously described (10,12,21). Briefly, ELISA plates were coated with 0.5 g of T. evansi antigen prepared from whole-cell lysate in 0.1 M carbonate-bicarbonate buffer (pH 9.6), kept overnight at 4°C, and further blocked with 5% skimmed milk in PBST (PBS plus 0.05% Tween 20) for 1 h at 37°C.…”

Evaluation of Formol Gel Slide Test With Reference to Blood Microscopy and Enzyme Linked Immunosorbant Assay for Diagnosis of Surra in Cattle

“…However, finding of parasite in blood is very uncertain due to latent carrier status, low grade or intermittent parasitaemia in clinical cases. Several serological tests have been developed for detection of parasite antigen or antibodies in T. evansi infected animals (Jeyabal et al, 2003;Kumar et al, 2013;Yadav et al, 2014). These tests although specific with varying sensitivities are more suitable for herd screening in a geographical location.…”

Parasitological, biochemical and clinical observations in ponies experimentally infected with Trypanosoma evansi

“…In India, trypanosomosis caused by T. evansi is enzootic, since it affects many species of domestic and wild animals. Several sporadic outbreaks of equine trypanosomosis have been reported from different states (Yadav et al, 2012;Kumar et al, 2013). The course of the disease lasts from one week to six months (Woo, 1977) and usually results in emaciation and death.…”