Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)

The helminth fauna of M nivalis in Iberia is formed mainly by oligoxenic species, such as 71 mustelae, A. putorii, M. patens, S. mustelorum and F. martis. However, this parasitic fauna shows certain peculiarities as shown by the Mustelids in Central and Eastern Europe. One of these peculiarities is the absence of Trematodes and Acanthocephales. On the contrary, in the Peninsula a greater richness of parasites transmitted by Invertebrates as intermediate hosts (Molluscs and Arthropods) is observed. The absence of species such as E. squamula or Euparyphium melis (Schrank, 1788), among the Trematoda, or Centrorhynchus spp., among the Acanthocephala, parasitizing M nivalis in Iberia can be considered as surprising. In fact, the helminths were reported in Iberia parasitizing other Mustelids (Feliu et al. 1989, Miquel 1993, Motje 1995). Among the Nematodes, the most evident absences occur in the Trichuridae and Ascarididae families. As far as the Metastrongyloidea is concerned, the occurrence of C. melesi parasitizing M nivalis has not been detected outside the Iberian Peninsula. From a quantitative point of view, the helminth showing a higher prevalence and parasitic load is M patens. In fact, it is the helminth best adapted to all the Iberian Mustelids (Feliu et al. 1991, Motje 1995). Furthermore, taking into account the abundance indexes, M. patens is the species most dominant in the helminth community of the weasel, in all the subpopulations. Among the rest of species of the community, only T. mustelae, A. putorii, and S. mustelorum can be considered as well-adapted species, because they have been found in all the subpopulations. These species are, in general, codominant in the general analysis and among the helminthfaunas of the samples. Except for S. nasicola (non representative data), the rest of parasitic species show in Iberia a prevalence always lower than 5% and are immigrant species. Therefore, the chorology of the majority of species is rather peculiar. Thus, Crenosoma melesi and Mastophorus muris show a marked preference for the population of the Montseny Massif, where they appear as codominant species. This is the principal reason for the fact that the Montseny appears as the area where M nivalis shows the most diversified parasite fauna. The parasitic communities of the two host subpopulations established as regards to sex do not differ markedly from each other. At a qualitative level, the absence of Trichinella sp. in males and C. melesi and M. muris in females are accidental. When comparing both samples, statistically significant differences were not detected either for the prevalences or for the intensities. However, the prevalences of M. patens and of the other geohelminth (SI mustelorum) are uneven. In the case of males a predominance of one species over the other does not exist. On the other hand, for the females the higher prevalence of M. patens (50%) over S. mustelorum (13.3%) is statistically significant (chi square test; pO.01). The geographical location of the host seems to influence the helminth fauna of M nivalis more markedly than sex does. This is obvious both at a qualitative (number of species) and at a quantitative level (prevalences and parasitic burden). At a qualitative level, as we have already mentioned, it stands out that the community from the Montseny Massif is the most diverse. From a quantitative point of view significant differences are observed, for the nematodes prevalence (NP) and for the total parasitation (TP), between the Montseny Massif and the other four areas considered. From the chi square tests the differences are: MON-NW (NP and TP p<0.01); MON-NE (NP pO.01 and TP p<0.05); MON-CN (NP and TP p<0.01); MON-CS (NP and TP p<0.01). Differences between the populations NW-CS (NP and TP p<0.05) have also been found.