Contrasting pattern of Eimeria spp. oocyst emission in chamois (Rupicaprar.rupicapra) and red deer (Cervus elaphus) from Italian Alps

Parasites have often been considered as partial limiting factor of wildlife populations, underlining their impact on animal welfare. Despite previous surveys showed a possible relation between coccidian infection and juvenile mortality in livestock, little information is available on the detrimental effects of protozoa infections on wild ungulate population dynamics. Therefore we investigated oocyst emission in chamois (Rupicapra r. rupicapra) and red deer (Cervus elaphus) as dominant species in Alps whose census data are available, and we modelled through Generalized Linear Models in order to evaluate which epidemiological factors may influence oocyst emissions. Overall 96 chamois and 68 red deer faecal samples have been monthly collected through transects within the Alpe Veglia-Alpe Devero Natural Park, in 2011 and 2013 from June to November. Samples have been analyzed by FLOTAC techniques to estimate oocyst per gram of faeces (OPG). The overall oocyst prevalence was 66% and 75% respectively in chamois and red deer. In chamois, kids emissions are significantly higher than those of adults, suggesting that classes 0 are more susceptible than older age classes due to their immature immune system. Moreover higher summer faecal OPG emissions were recorded in both chamois and red deer suggesting the positive effects of advantageous conditions of temperature and humidity even though the presence of newborn could also play a role influencing this major emission. In red deer there are no significant differences between classes 0 and adults, nevertheless in 2013 calves oocyst emissions were significantly higher than those registered in 2011. This could be caused by the snow coat persistance until July that causes energy expenditures in calves and could reduce the strength of their immune system. Future in-depth analyses about Eimeria spp. and other protozoa, such as Giardia spp. and Cryptosporidium spp., because of their impact on populations, have been planned, also in relation to data emerged from census, to investigate any influence between them.