Clinicopathological Study on Abu Rigaiba Syndrome (Botulism) in Sheep in River Nile State

Abstract

The present work was conducted to investigate the clinical signs and pathological lesions of sheep botulism in River Nile at Al Butana area. Many outbreaks of botulism were detected in sheep in River Nile State. In 10406 sheep flocks, 879 were affected and 797 were died with morbidity rate 8.4% and mortality rate 7.6%. Mortality among infected sheep was 90.6%. The main symptoms were flaccid tetraparesis leading to tetraplegia that was often accompanied by twisted neck, tongue paralysis, continuous tail movement, and loss of appitite, profuse salivation, and nasal discharge and muscle tremors then complete recumbency occured. Ambulatory sheep had uncoordinated and swaying gaits with hypometria and weakness, mainly of the hind limbs. Then recumbent ambulatory sheep with twisted neck eventually died. The recumbent sheep were necropsied. The gross lesions were conestion in all organs, congestion and edema of lungs, pale and fatty liver, fragile muscles congested and inflamed intestine. Accumulation of gases in large intstines and enlarged lymph nodes were observed. On histopathology sections, severe conestion, edema and emphysema were observed in lungs, percarditis, and fatty change in hepatic cells was seen. No significant changes were seen in brain tissues. Samples of the liver, gut and rumen content were collected from the sheep and examined for botulism using the mouse serum neutralization test. Marked osteophagia was observed when the sheep had access to bones in the pasture, and the farmer mentioned that osteophagia was common among sheep of the many survived flocks. Sample from the plant, Aristida annulata (Alghabash); the most abundant forage available for the sheep, was collected and authenticated at the herbarium of Aromatic and Medicinal Plant Institute, National Center for Research, Khartoum Sudan. It contained 2800 mg/kg of Ca and 450 mg/kg of P. One soil sample contained v 58.12 mg/kg of Ca and 2.02 mg/kg of P. Epidemiological data and the history of the outbreak were collected on visits to the flocks being affected. During the first visit, 9 affected animals were examined clinically. The serum samples of seven sheep were examined for urea and creatinine concentrations, and serum activities of creatinine kinase (CPK), aspartate-aminotransferase (AST), and glutamyltransferase (GGT). Two recumbent sheep were euthanized and necropsied. Samples from multiple organs and the central and peripheral nervous tissue were collected and processed for histological examination. Samples of the CNS were examined. It is concluded that in these outbreaks, botulism was severely occurred due to loss of green fodders and animals licking bones of dead animals. Drastic economical losses happened due to this syndrome and periodical vaccination is needed to avoid thisbotulism