Use of a Novel Real-Time PCR to Investigate Anthelmintic Efficacy Against Haemonchus contortus in Sheep and Goat Farms

Gastrointestinal nematode infections are due to a wide number of helminthic genera and species, representing a major concern in goat and sheep farming and leading to different health issues and a general economic loss. Traditional diagnostic tools do not allow for a specific identification and, although a shift towards molecular diagnostic techniques is ongoing, species or genus-specific diagnosis is still poorly implemented. This study describes the development of a novel real-time PCR method for diagnosing Haemonchus sp. and its relative abundance in mixed infections in grazing ruminants. The method employs two primer/probe sets targeting the 18S-rRNA-ITS1-5.8S-ITS2 region: one shared by all strongylids (GEN) and another specific to Haemonchus sp. (HAEM). The method demonstrated optimal efficiency and determination coefficients when applied to serial dilutions of DNA extract. It was then applied in Faecal Egg Count Reduction Test (FECRT) trials conducted on five sheep and five goat farms in northeastern Italy. Seven farms were suspected of overall resistance and only one farm of Heamonchus-related resistance. The results proved the genus-specific approach as valuable in interpreting treatment outcomes and showing concerning levels of anthelmintic treatment ineffectiveness. Further research and sensitization activity is required to encourage the adoption of the method by local farmers and veterinarians.