The global and regional prevalence of oestrosis in sheep and goats: a systematic review of articles and meta-analysis

BackgroundOestrosis, caused by the larvae of Oestrus ovis, commonly known as sheep nose bot, is an obligatory cavitary myiasis of sheep and goats. Oestrus ovis is a widespread parasite, but little is known about the prevalence of oestrosis at the global and broad geographical levels. The present study aimed to explore the epidemiology of oestrosis at the global and regional level to estimate prevalences and their associated factors using a systematic approach. This is, to the author's knowledge, the first meta-analysis of oestrosis in sheep and goats.MethodsPublished articles were obtained from nine electronic databases (PubMed, CAB Abstracts, Web of Science, Scopus, UCB library, Medline, Biosis Citation Index, Indian journals and Google Scholar) reporting the prevalence of O. ovis in sheep and goats from 1970 to 2018. Pooled prevalences were estimated using a random effect meta-analysis model.ResultsSixty-six studies were eligible, and data from 40,870 sheep and 18,216 goats were used for quantitative analysis. The random effect estimated prevalence of oestrosis at the global level in sheep was 51.15% (95% CI: 42.80-59.51%) and in goats was 42.19% (95% CI: 33.43-50.95%). The pooled prevalence estimates for Africa, Asia, Europe and the Americas were 47.85% (95% CI: 36.04-59.66%), 44.48% (95% CI: 33.09-55.87%), 56.83% (95% CI: 48.92-64.74%) and 34.46% (95% CI: 19.90-49.01%), respectively. Heterogeneity (I-2>80%) was detected in most pooled estimates.ConclusionsOestrosis is highly prevalent in many geographical regions of the world, especially in Europe and Africa. Factors that contribute to the pooled prevalence estimate of oestrosis need to be emphasised in any survey to estimate the true prevalence of oestrosis. Furthermore, there is a need for immunisation or implementation of other preventive measures to reduce the burden of oestrosis in sheep and goats and to improve the health and welfare status.