No abstract

The economic, veterinary, and medical impact of the parasite Fasciola hepatica, liver fluke, is difficult to alleviate due to increasing incidences of resistance to the principal anthelmintic drugs. These have occurred in widely separated regions. The rate of response to selection imposed by such drugs will be dependent on the genetic variation present in the F. hepatica gene pool, but this is at present unknown. We have assessed the genetic diversity of mitochondrial haplotypes found in the infrapopulation of flukes recovered from a calf of known provenance and from six other cattle and sheep hosts located in Ireland and four from elsewhere. Our results revealed that at least ten different mitochondrial composite PCR-restriction fragment length polymorphism haplotypes had been acquired by a single animal in 1 year, and there was comparable diversity in six other definitive hosts carrying field-acquired infections. The extent of divergence between these fluke lineages suggests that they predate the last ice age and, thus, cannot have developed in Northern Europe. A consequence of this high level of diversity is that there will be frequent selection for anthelmintic resistance and rapid responses to climatic changes.

No abstract

Risk factors related to herd and farmer status, farm and pasture management, and environmental factors derived by satellite data were examined for their association with the prevalence of F. hepatica in sheep and goat farms in Thessaly, Greece. Twelve farms (16.2%) and 58 farms (78.4%) of 74 had evidence of infection using coproantigen and serology respectively. The average normalized difference vegetation index (NDVI) of farm location for 12 months before sampling was the most significant environmental risk factor for F. hepatica infection based on high seropositivity. The risk of infection increased by 1% when the value of NDVI increased by 0.01 degree. A geospatial map was constructed to show the relative risk (RR) of Fasciola infection in sheep and goat farms in Thessaly. In addition, geospatial maps of the model-based predicted RR for the presence of Fasciola infection in farms in Thessaly and the entire area of Greece were constructed from the developed model based on NDVI. In conclusion, this study demonstrated that Thessaly should be regarded as an endemic region for Fasciola infection and it represents the first prediction model of Fasciola infection in small ruminants in the Mediterranean basin.

Gastrointestinal (GI) parasitic infections of sheep and goats were investigated in 69 farms located in Thessaly region of Greece, characterized by temperate Mediterranean climate, during two consecutive seasons. A total of 557 fecal samples were collected. Helminth eggs were detected in 44 (7.9%) samples. Strongyle-type eggs were found in 19 (3.4%) samples, Nematodirus spp. eggs in 6 (1.1%) samples, Trichuris spp. eggs in 16 (2.9%) samples, Fasciola hepatica in 3 (0.5%) samples, and Dicrocoelium dendriticum in 1 (0.2%) sample. Coccidian oocysts were found in 36 (6.5%) samples. Risk factors related to animal and farmer status, farm and pasture management, and environmental factors derived by satellite data were examined for their association with the prevalence of helmith infections. A logistic regression model showed that the educational level of farmers and the elevation of farm location were associated with helminth infections.