Lung parasites of the genus Metastrongylus Molin, 1861 (Nematoda: Metastrongilidae) in wild boar (Sus scrofa L., 1758) in Central-Italy: An eco-epidemiological study

The respiratory tracts of 57 wild boars (Sus scrofa L. 1758) hunted in central Italy during the 2011/2012 hunting season were examined to detect the presence of lung worms. Fifty-five out of 57 animals (96,5%) were positive. Five species of Metastrongylus were detected and their prevalence was as follows: Metastrongylus asymmetricus Noda, 1973 (91.2%), Metastrongylus confusus Jansen, 1964 and Metastrongylus salmi Gedoelst, 1923 (87.7%), Metastrongylus apri Gmelin, 1790 (80.7%), Metastrongylus pudendotectus Vostokov, 1905 (70.2%). In most cases multi-species infection was observed. The highest parasite load was found in young animals (<1 year old). The Metastrongylus genus sex ratio (M/F) had a range from 1:4.8 to 1:1.5 in favor of females. The Simpson and Shannon-Wiener indices showed a moderate uniformity in parasite community composition. The Fager index highlighted a high degree of affinity among all pairs of selected parasites. The whole parasite population showed an aggregate distribution. Our findings confirm that these parasites are widespread in the wild boar population. The establishment of outdoor domestic pig farming in the same area of the game preserve could pose the risk of infection to domestic animals. Further studies will be needed to understand the factors involved in the presence and prevalence of the intermediate host as well as the population dynamics of Metastrongylus spp.