Parasite community structure and parasite groups relationships in Wood Mouse (Apodemus sylvaticus)

Macro- and micro-parasites community structure studies are important to understand host-parasites interaction. Interactions between parasite groups within hosts can range from the mere coincidence of more than one groups in... [ view full abstract ]

Macro- and micro-parasites community structure studies are important to understand host-parasites interaction. Interactions between parasite groups within hosts can range from the mere coincidence of more than one groups in the same host, through one group influencing the environment within that host in a way that benefits or impairs the survival of the second group.

Wood mice (Apodemus sylvaticus) (n=126) were included in the study. Prevalence and abundance of gamasid mites, fleas, ticks, gastrointestinal (GI) nematodes, GI cestodes and GI trematodes and prevalence of Bartonella spp. and Calodium hepaticum were determined. Overall parasite community structure was evaluated using C-score index, which quantifies the degree of species co-occurrences by null models analysis. Prevalence and abundance relationships between parasites group’s pairs were tested using X2 or Fisher’s exact test and Mann-Withney U test or Spearman’s r respectively.

Observed C-score was significantly smaller than expected by chance (p<0.001), indicating a positive co-occurrence of parasites groups on wood mice, therefore an aggregated community structure. We found 14 of significant associations, of which all but one were positive. Gamasid mites and fleas were involved in eight of 14 and seven of 14, respectively, significant positive relationships. Conversely GI nematodes were not associated with any other parasite group. Parasites assemblages tend to be aggregately distributed among hosts and positive co-occurrence were consistently detected in parasite communities. The results suggest that infestation by gamasid mites and fleas may be more detrimental for hosts than other infection by other parasite groups. This may be caused by exploiting host immune system and facilitating parasitization by other parasite groups.