Effect of socio-ecological factors and parasite infection on body condition of Brown Mouse Lemur Microcebus rufus (Mammalia: Primates: Cheirogaleidae)

Various studies in ecology have shown the relationship between body condition and parasitic loads in nonhuman primates, however, little information is available regarding prosimians such as lemurs. In this study, the synergistic effect of parasite infection and socio-ecological factors on the body condition of Microcebus rufus in the family Cheirogaleidae was analyzed in Ranomafana National Park in southeastern Madagascar. This lemur species is characterized by its ability to adapt to different types of forest, and by seasonal fattening. Based on the factors considered, this species is, therefore, a good model for the study of body condition and ecology of infectious diseases in lemurs. Floatation and direct observation techniques were used for examination of parasite infection. Two indices considering body condition were analyzed: volume index (VI) and condition index (CI), the residual between the mass observed and the corrected mass. The generalized linear mixed model (GLMM) was used to model the synergistic effect of parasite infections and socio-ecological factors on variation in body condition, with the identity of individuals used as a random factor. We identified five species of helminths, one species of protist, and one species of lice which infected the 204 mouse lemurs captured. There was a sexual difference for all measures of the parasite infection. The more parasite species an individual was infected with, the smaller was its body size according to the Volume Index that reflects deposits of subcutaneous fat. Individuals with more positive Condition Index values, particularly females, excreted more parasite eggs or oocyst in their faecal matter. The results suggest that an individual’s body condition constitutes an indicator of risk of parasite infection and transmission.

Tracking year-to-year changes in intestinal nematode communities of rufous mouse lemurs (Microcebus rufus)

SUMMARYWhile it is known that intestinal parasite communities vary in their composition over time, there is a lack of studies addressing how variation in component communities (between-hosts) manifests in infracommunities (within-host) during the host lifespan. In this study, we investigate the changes in the intestinal parasite infracommunities in wild-living rufous mouse lemurs (Microcebus rufus) from Ranomafana National Park in southeastern Madagascar from 2010 to 2012. We used high-throughput barcoding of the 18S rRNA gene to interrogate parasite community structure. Our results show that in these nematode communities, there were two frequently occurring putative species and four rarer putative species. All putative species were randomly distributed over host individuals and they did not occur in clear temporal patterns. For the individuals caught in at least two different years, there was high turnover of putative species and high variation in fecal egg counts. Our study shows that while there was remarkable variation in infracommunities over time, the component community was relatively stable. Nevertheless, the patterns of prevalence varied substantially between years in each component community.