EFFICACIES OF BUPARVAQUONE AND ISOMETAMIDIUM CHLORIDE IN THE TREATMENT OF EXPERIMENTAL TRYPANOSOMA EVANSI INFECTION IN DONKEYS

EFFICACIES OF BUPARVAQUONE AND ISOMETAMIDIUM CHLORIDE IN THE TREATMENT OF EXPERIMENTAL TRYPANOSOMA EVANSI INFECTION IN DONKEYS

Abstract

The aim of this study was to evaluate the efficacies of Buparvaquone (an anti-theilerial drug) and Isometamidium chloride (a standard trypanocide) in the treatment of experimental Trypanosoma evansi infection in donkeys. Twenty four apparently healthy donkeys between 11 -15 months old were used for the experiment. Six animals were assigned to each of the experimental groups A1, A2, A3 and B at random. Baseline values of vital parametres, body weight, haemogramme and serum biochemicals/electrolytes were evaluated 4 times at 7 days interval pre-infection. Donkeys in groups A1, A2 and A3 were infected with 2mL of inoculum (about 2.0×106 Trypanosoma evansi, Sokoto isolate) through the jugular vein, while group B was un-infected control. On day 28 post-infection, groups A2 and A3 were treated with Isometamidium chloride (1%), 0.5mg/Kg I.M. once and Buparvaquone (5%), 2.5mg/Kg I.M. twice, 3 days apart respectively. The animals were re-evaluated for parasitaemia post-infection and post-treatment using Haematocrit Centrifugation Technique and Mice Inoculation Test. Clinical signs, body weight changes, haemogramme picture and serum biochemical/electrolytes parametres were also re-evaluated. At post-mortem, internal organs were examined for gross lesions and tissue samples were taken, prepared and examined for histopathological changes. Organs impression smears were also prepared and examined for parasites. System Analytical Statistics (SAS) corporation-2010 was used to determine means of parametres which have been presented on tables and graphs. Analysis of Variance was used to compare group means of variables at 95% confidence level. Probability values less than 0.05 (p<0.05) were considered statistically significant. From the results, it was concluded that the pre-patent and incubation periods were 3-4 days and 3-7 days respectively. Parasitaemia was undulating in the acute stage of infection but disappeared in the chronic stage from peripheral blood of infected-untreated animals from day 100 post-infection. Mice inoculation test revealed latent parasitaemia in the infected-untreated group with death of all mice used within 15 days post-inoculation from heavy parasitaemia. Isometamidium chloride, incompletely cleared parasitaemia in treated donkeys on day 11 post-treatment but showed 60% relapse on day 100 pos-treatment with low (only 1+) parasitaemia but no mice died during the 48 days of observation. Buparvaquone treated animals also showed disappearance of parasites from peripheral blood on day 49 post-treatment (depression) but recorded relapse in all treated donkeys and all mice used died from heavy parasitaemia within 23 days post-inoculation. The acute clinical signs were mild pyrexia, hyperpnoea, tarchycadia and lethargy, urticaria with alopecia and lymphadenopathy. Penile erection, rectal prolapse, rough hair coat, urticaria with alopecia, anaemia, isolation behavior, bilateral epiphora, pale mucous membranes were also recorded with acute mortality of 2/18(11%) and chronic mortality of 1/18(5.6%). The chronic signs were progressive emaciation, ventral abdominal oedema and recumbency. The haemopathological changes were anaemia, lymphopenia. Serum biochemical alterations were hypoglycemia, hypoproteinaemia, hypoalbuminaemia and elevated alkaline phosphatase. Electrolyte changes were hypocalcaemia and declined serum bicarbonate level. However, Isometamidium-treated animals showed hyperphosphatemia, hyperkalemia post-treatment. The gross pathological lesions were lungs congestion, frothy exudates in trachea and bronchi, hydrothorax, hydroperitoneum, adherence of renal capsule to the renal cortex and serous atrophies of mesenteric, peri-renal and coronary fats. The histopathological findings were congestion and mononuclear cellular infiltrations in lungs and liver. Haemosiderosis and lymphocytes depletion were also observed in the spleen as prominent features of Trypanosoma evansi infection in donkeys. In conclusion, Isometamidium caused incomplete cure while buparvaquone treatment resulted in depression of parasitaemia.

EFFICACIES OF BUPARVAQUONE AND ISOMETAMIDIUM CHLORIDE IN THE TREATMENT OF EXPERIMENTAL TRYPANOSOMA EVANSI INFECTION IN DONKEYS