Haemonchus contortus: spatial risk distribution for infection in sheep in Europe

• Main Authors: Laura Rinaldi, Dolores Catelan, Vincenzo Musella, Lorenzo Cecconi, Hubertus Hertzberg, Paul R. Torgerson, Fabien Mavrot, Theo de Waal, Nikolaos Selemetas, Tom Coll, Antonio Bosco, Annibale Biggeri, Giuseppe Cringoli
• Format: Article
• Language: English
• Published: PAGEPress Publications 2015-03-01
• Series: Geospatial Health
• Subjects: Haemonchus contortus, gastrointestinal strongyles, spatial statistics, geographical information systems, sheep, Europe
• Online Access: http://www.geospatialhealth.net/index.php/gh/article/view/355

<em>Haemonchus contortus</em> is a species of gastrointestinal strongyles of primary concern for sheep. This highly pathogenic, blood-feeding helminth negatively influences animal health, welfare and productivity. In order to elucidate the current scenario in terms of prevalence and intensity of <em>H. contortus</em> infection in sheep farms across Europe, a standardized crosssectional survey was conducted in three pilot areas in Ireland, Switzerland and Italy, all part of the EU funded GLOWORM project. Two consecutive field surveys (in 2012 and 2013) were conducted in the three countries in the same period (August-October) in 259 sheep farms in total. Harmonized, diagnostic procedures (from farm to laboratory) based on pooled samples, the FLOTAC technique and coproculture were used. The georeferenced parasitological results were modelled (at the pilot area level) following a Bayesian geostatistical approach with correction for preferential sampling and accounting for climatic and environmental covariates. The observed <em>H. contortus</em> prevalence rates did vary between the countries showing high values in Switzerland (77%) and Italy (73%) compared to Ireland (4%). Spatial patterns of <em>H. contortus</em> distribution were detected in Switzerland and Italy with a north-south gradient. The latent factor analysis highlighted the importance of seasonality and annual cyclicity within country (particularly in southern Italy), while mean temperature and rainfall dominated between country variations in the prevalence of <em>H. contortus</em> infection.