Molecular epidemiology of camel contagious ecthyma in Arero district, Ethiopia

Abstract

BackgroundWhile dromedary camels (Camelus dromedarius) were traditionally believed to be resistant to most livestock diseases, research has demonstrated that they are susceptible to a large number of infectious agents. Based on the clinical appearance of typical lesions, camel contagious ecthyma, caused by a Parapoxvirus, is thought to be one of the most common viral diseases of dromedary camels in Ethiopia.MethodsA cross-sectional study was conducted from November 2013 to April 2014 in Arero district of Borana Zone, Oromia Regional State of Ethiopia to investigate the epidemiological aspect of camel contagious ecthyma and molecularly identify the causative agent. A polymerase chain reaction based on B2L gene-specific primers of Parapoxvirus was used for confirmatory diagnosis of the disease from camels showing suspected clinical signs of Parapoxvirus infection.ResultsThe majority (87%) of camel owners reported the occurrence of camel contagious ecthyma outbreaks in their herds in the past year (a year preceding the start of the study). The overall morbidity and mortality rates attributed to camel contagious ecthyma were 20% (95% CI 11–36%) and 6.3% (95% CI 5.2–7.6%), respectively. Camel calves had higher odds of becoming affected by the disease than adults [OR = 3.44 (95% CI 2.29–4.09)] and the difference was statistically significant. The disease has a marked seasonality with most of the cases occurring during the rainy season. Acacia trees significantly contribute to virus dissemination by damaging the lips of browsing camels. Confirmatory diagnosis of the suspected cases using conventional polymerase chain reaction generated the expected amplification product of 1200 bp for one of the samples.ConclusionsThis study confirms the presence and importance of camel contagious ecthyma in Ethiopia and establishes the basis for further research.