Epsilon Archive for Student Projects

Abstract

Parascaris spp. are prevalent equine gastrointestinal nematodes that predominantly infect foals. The infection causes impaired welfare and can have a lethal outcome due to complications such as intestinal obstruction. Due to a prepatent period of 10-14 weeks, diagnosis with coprological techniques is limited and therefore most foals are routinely dewormed during their first year without knowledge of infectious status. The parasite is showing an alarming emerging resistance to numerous anthelmintic drug classes, limiting the possibilities of treatment. Diagnostics through serological techniques have been developed for the related pig roundworm, Ascaris suum, using an indirect ELISA targeting either Ascaris suum haemoglobin (AsHb) or L3-Lung antigens. This study investigated the possibility of using a modified version of the indirect ELISA protocol, targeting the same AsHb and L3-Lung antigens to identify Parascaris spp. infection in foals. Two farms were included with a total of 15 foals concluding the study. The foals were sampled for blood for serum extraction from two weeks of age and followed at four-week intervals. Faecal samples were examined from six weeks with about two-week intervals until positive for Parascaris spp. eggs to determine a patent infection. The results showed that antibodies for Parascaris spp. could be detected with both the AsHb ELISA and L3-Lung ELISA. Moreover, an initial increase in antibody levels were observed for both antigens. A significant correlation between antibody levels in twoweek-old foals and their mother was found, indicating passive transfer of antibodies via colostrum. The antibody levels of the foals thereafter decreased from the first to the second and third sampling occasion and then significantly increased to the fourth occasion for both AsHb and L3-Lung ELISAs, indicating an immunological response to the Parascaris spp. infection. This study shows the potential of developing a clinically applicable serological technique for Parascaris spp. The possibility of a clinically applicable test could be used for targeted deworming and decrease the anthelmintic use, thereby limiting the emerging anthelmintic resistance in Parascaris spp. and reducing the environmental contamination with residues of anthelmintic compounds.