OUTBREAK INVESTIGATION OF LUMPY SKIN DISEASE; ISOLATION AND MOLECULAR CHARACTERIZATION OF THE VIRUS IN SOUTH WOLLO ZONE, NORTHERN ETHIOPIA
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Date
2018-06
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Abstract
Lumpy skin disease, caused by Lumpy skin disease virus is one of the most economically important cattle diseases in Ethiopia. The current study was conducted from October 2017 to May 2018 with the objective of outbreak investigation and isolation and molecular characterization of the virus from the outbreaks occurred in South Wollo zone. All ages and breeds of cattle from reported disease outbreaks were the study subjects. Cattle were examined for the presence of skin lesions and tissue samples were collected aseptically and transported to National Animal Health Diagnostic and Investigation Centre laboratory. Virus isolation was done by growing on Vero cells and molecular characterization was carried out by extracting DNA of the virus and the extract was subjected to real time polymerase chain reaction assay. Based on clinical examination of cattle at risk (350 cattle), 55 cattle were affected and 10 were died. The morbidity, mortality and case fatality rates were 15.71%, 2.86% and 18.18%, respectively. The highest morbidity (21.42%) was in Kalu/07 PA and lowest (11.76%) in Tehuledere/023 PA. Mortality and case fatality rates were higher in male than in female cattle (3.29 and 28.57%; 2.38 and 11.76% respectively). Morbidity was also higher in crossbred cattle with lower mortality and case fatality rates than local ones. Age wise higher morbidity was observed in younger (16.36%) than adult cattle (15.41%) and high morbidity rates regardless of vaccination status of the animals. Out of 20 samples10 were grown on Vero cells and all of them showed cytopathic effect due to virus infection and 17 samples were positive by Polymerase chain reaction. In conclusion, the disease caused high morbidity rates that could cause great loss to the farmers. Isolation and characterization of the virus from these outbreak cases shows the occurrence of the disease. Observation of the disease in vaccinated cattle shows concern on the efficacy of the vaccine. While prevention of movement of the diseased animals along with vector control and regular annual vaccinations play great role in disease control, further studies on the efficacy of the currently used vaccines and awareness creation for cattle owners are highly recommended.
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A Thesis submitted to the College of Veterinary Medicine and Agriculture of Addis Ababa University in partial fulfillment of the requirements for the degree of Master of Veterinary Science in veterinary Microbiology
Keywords
Lumpy skin disease virus, virus isolation, Out-break investigation