A comparison of the helminth faunas of wild and farm-reared red-legged partridge

More than 4 million farm-reared red-legged partridge (Alectoris rufa; hereafter partridge) are released each year in autumn for harvest purposes in Spain. We compared the helminth fauna of 122 juvenile, farm-reared partridge from 9 farms around Spain with that of 174 wild partridge from 7 harvest areas where no releases currently are conducted. We examined the digestive tract, liver, and trachea. Fourteen helminth species were retrieved (6 from farm-reared partridge, 9 from wild partridge). No trematode or nematode species were shared by both groups of partridge, and only 1 cestode species was present in both populations. Monoxenous nematodes were the most prevalent species found in farm-reared birds. Ascaridia compar, a parasite of the rock partridge (A. graeca) previously unreported in the red-legged partridge, was found in 4 facilities. Heteroxenous helminths, such as Dicrocoelium sp., Raillietina tetragona, and Cheilospirura gruveli, predominated in wild partridge. The prevalence and intensity of helminths in some farmed partridge were higher than expected considering the routine use of antihelminthics in these facilities. Thus, released partridge may introduce new parasites into wild populations, come into contact with parasites of wild partridge, and be negatively affected by their parasite burdens after release. These risks require further study.This is a contribution to CICYT PB1-02-004, to FEDER-UE 1FD1997-2299, and to a joint project CSIC/Principado de Asturias.Peer reviewe