Prevalence, intensity and seasonality of gastrointestinal parasites in abattoir horses in Germany

Prevalence and intensity of gastrointestinal parasites were studied through a longitudinal survey in 400 horses over a 17-month period in an abattoir in Germany. Three hundred and ten horses (77.5 %) were demonstrated harbouring endoparasites either by direct recovery of parasites from the digestive tract and/or in terms of faecal egg counts (strongyles). The following parasites were found (percentage prevalence, range of counts): Gasterophilus intestinalis larvae (2.25 %, 1-154), Gasterophilus nasalis larvae (0.25 %, 44), Trichostrongylus axei (11.0 %, 1-3,620), Habronema majus (8.0 %; 1-422), Habronema muscae (26.5 %, 1-3,563), Habronema spp. fourth-stage larvae (5.5 %; 1-1,365), Parascaris equorum (total prevalence 11.3 %; adults 8.8 %, 1-178; fourth-stage larvae 2.5 %, 5-2,320), Anoplocephala perfoliata (28.5 %, 1-2,013) and Paranoplocephala mamillana (1.0 %, 1-11). Strongyle eggs (>= 10 eggs per gram of faeces) were recorded in 60.8 % of the horses (10-6,450 eggs per gram of faeces). Prevalences of infection with T. axei, P. equorum and strongyles did not show a correlation to specific seasons. In contrast, a significant variation among seasons of collection was shown for the infection rates of Habronema spp. (p<0.05) and A. perfoliata (p<0.001). Seasonal prevalence of Habronema spp. infection was significantly (p<0.01) higher in summer (39.0 %), autumn (34.8 %) and winter (36.5 %) than in spring (18.7 %), and A. perfoliata were significantly (p<0.001) more often recorded during autumn (36.1 %) and winter (36.5 %) than in spring (17.3 %) and summer (15.9 %). Prevalences of T. axei, Habronema spp., strongyles and A. perfoliata in male and female horses were almost alike, but ascarids were significantly (p=0.025) more often recorded in male than in female horses.