Cluster analysis of fasciolosis in dairy cow herds in Munster province of Ireland and detection of major climatic and environmental predictors of the exposure risk

Abstract

Abstract. Fasciolosis caused by Fasciola hepatica is a widespread parasitic disease in cattle farms. The aim of this study was to detect clusters of fasciolosis in dairy cow herds in Munster Province, Ireland and to identify significant climatic and environmental predictors of the exposure risk. In total, 1,292 dairy herds across Munster was sampled in September 2012 providing a single bulk tank milk (BTM) sample. The analysis of samples by an in-house antibody-detection enzyme-linked immunosorbent assay (ELISA), showed that 65% of the dairy herds (n = 842) had been exposed to F. hepatica. Using the Getis-Ord Gi* statistic, 16 high-risk and 24 low-risk (P <0.01) clusters of fasciolosis were identified. The spatial distribution of high-risk clusters was more dispersed and mainly located in the northern and western regions of Munster compared to the low-risk clusters that were mostly concentrated in the southern and eastern regions. The most significant classes of variables that could reflect the difference between high-risk and low-risk clusters were the total number of wet-days and rain-days, rainfall, the normalized difference vegetation index (NDVI), temperature and soil type. There was a bigger proportion of well-drained soils among the low-risk clusters, whereas poorly drained soils were more common among the high-risk clusters. These results stress the role of precipitation, grazing, temperature and drainage on the life cycle of F. hepatica in the temperate Irish climate. The findings of this study highlight the importance of cluster analysis for identifying significant differences in climatic and environmental variables between high-risk and low-risk clusters of fasciolosis in Irish dairy herds.

Detection of major climatic and environmental predictors of liver fluke exposure risk in Ireland using spatial cluster analysis

“…These results are in accordance with findings indicating that major predictors of liver exposure included (i) the total number of wetdays (Selemetas et al, 2015a,b), (ii) the rainfall in August (McCann et al, 2010a;Selemetas et al, 2015b) which is vital for the development of the intermediate snail-host and parasite (Torgerson and Claxton, 1999), and (iii) the rainfall in September (McCann et al, 2010a) highlighting the importance of wet pastures for the intermediate snail-host. Finally, it is important to stress the negative correlation of liver fluke exposure risk with rainfall levels in August.…”

“…Under the temperate Irish climate these findings may underline the need for a consistent set of optimal conditions of moisture and soil type for the survival and development of the free-living stages of F. hepatica and the intermediate snail host, including embryonation, hatching of miracidia, and the emergence of cercariae from snails (Torgerson and Claxton, 1999). These differences in climatic and environmental variables were consistent with the findings of studies, which suggested that rainfall Yilma and Malone, 1998;McCann et al, 2010a,b;Bennema et al, 2011;Martins et al, 2012), total wetdays (McCann et al, 2010a;Selemetas et al, 2015a) and raindays (Selemetas et al, 2015a), NDVI (Fuentes, 2004;Fuentes et al, 2005;Fuentes, 2006;Durr et al, 2005;Selemetas et al, 2015b), temperature Yilma and Malone, 1998;Bossaert et al, 1999;McCann et al, 2010a,b;Martins et al, 2012) and soil type (McCann et al, 2010a;Selemetas et al, 2015a) may play a role in the exposure to liver fluke. In addition, the association of poorly drained soils with high-risk clusters reflects the importance of impeded drainage to the transmission of fasciolosis, which is in accordance with the positive association between poor drainage and disease risk .…”

“…The Irish climate is mild without temperature extremes and with higher rainfall levels in the western part of country (Walsh, 2014). Several dairy cow farmers across Ireland participated in the current study, including those farmers (n = 1292) that took part in the study on cluster analysis in Munster province by Selemetas et al (2015b). In total, 4365 dairy farms throughout Ireland were sampled by an Irish private company on cattle breeding services, collecting bulk tank milk (BTM) samples from all its dairy farmer customers and a small creamery in County Donegal.…”

“…Rinaldi et al (2009) found clusters of fasciolosis in water buffaloes farms in Italy; Bennema et al (2011) detected spatial clusters of the disease in dairy cow farms in Belgium, and Selemetas et al (2015b) identified high-risk and low-risk regions of fasciolosis in Munster province of Ireland. However, a national-scale cluster analysis of the disease in dairy farms has not yet been conducted in Ireland to detect high-risk regions of fasciolosis and specific infection patterns.…”

Wat zijn de mogelijkheden om een leverbotinfectie van melkvee te voorkomen?

“…Vanaf het begin van de maand juli is er een piek in het aantal volwassen leverbotslakken die na de maand juli afloopt tot eind september. Begin oktober tot eind december kan er opnieuw een piek voorkomen indien de weersomstandigheden zich daarvoor lenen (Charlier et al, 2014;Hourdin et al, 2006 (Caron et al, 2007;Fairweather, 2011;Mas-Coma et al, 2009;Selemetas et al, 2015a). Onderzoek toont aan dat de meeste slakken worden gevonden in greppels en licht moerasachtige grond (Charlier et al, 2014).…”