Clinical and Epidemiological Evolution of Sheep Pox in Morocco

Abstract

Sheep pox is an infectious viral disease that affects specifically sheep and it is caused by the Capripoxvirus genus. The clinical signs include fever, diarrhea, difficulty breathing, nodules, lung lesions and death. In Morocco, the 2010 epidemic of sheep pox was characterized by the emergence of a nodular form of the disease. The local strain was isolated and the analysis of affected animals was positively confirmed by virus isolation and real-time polymerase chain reaction (RT-PCR). The epidemiological analysis of 911 data records showed that the virus is endemic in the country; an average of 350 cases per year with an epizootic evolution was observed in 2010. The incidence varies depending on provinces and the disease appears confined to the central and the eastern regions of the country where a very intensive sheep breeding activity is taking place. The statistical analysis showed that there is a positive correlation between the endemicity and the significant factor of the rural market (p = 0.006). The annual average morbidity and mortality rates were 2.96% (1.26% to 4.32%) and 0.71% (0.41% to 0.94%), respectively. The clinical findings associated to the epidemiological data analysis confirmed the presence of sheep pox in its nodular form and suggest that new pathogenic strains may have been introduced from Mauritania. The purpose of this work was to provide a better description of the spatiotemporal evolution of sheep pox disease based on some epidemiological indicators and to put forward plausible hypotheses regarding the emergence of the virus in order to implement an adequate control strategy.