Prevalence and risk factors of Haemonchus contortus in small ruminants in China: A systematic review and meta-analysis

Abstract

Haemonchosis, caused by Haemonchus contortus, is a major parasitic disease impacting ruminants, with serious consequences for animal health and ruminant production. Despite numerous studies on its prevalence, a comprehensive understanding of the disease in China is still lacking. To address this gap, we conducted a meta-analysis of studies examining H. contortus infection in sheep and goats across 17 provinces in China. A total of 52 studies were included, revealing an overall pooled prevalence of 72 %. The highest infection rate was observed in central China (71.31 %), with Henan and Liaoning provinces showing particularly high rates of 87.22 % and 85.57 %, respectively. Region, season, and climatic factors significantly influenced infection rates (P < 0.05), with free-ranging small ruminants and over 6 months of age being more susceptible. Additionally, the study emphasized that goats are more susceptible to infection than sheep, with infection rates rising after 2015. These findings highlight the widespread distribution of H. contortus in China and the urgent need for targeted control measures. Efforts should focus on improving management practices during the autumn season, implementing rotational grazing, using anthelmintics judiciously, and ensuring adequate nutritional support to reduce infection risks and minimize small ruminants production losses, all of which are crucial for advancing the small ruminants industry and fostering broader socioeconomic development.