Why are our roe deer short of breath? – prevalence and promotive factors of lung parasites in roe deer Capreolus capreolus in south‐eastern Germany

Abstract

The existence of bronchopulmonary nematodes in German roe deer Capreolus capreolus is well documented, with two types of lung parasites that have been described previously: Dictyocaulus capreolus and Varestrongylus capreoli. However, little is known about the impact of these parasites on their host animal or which parameters influence outbreak and intensity of infection. The aim of this study was to obtain new information on the relevance of factors such as season, environmental conditions or age, sex, and body mass of the infected roe deer. To obtain our results, the respiratory tracts of 762 roe deer from south‐eastern Germany were examined.In the sample, 42.5% of roe deer were infested with V. capreoli and 14.0% with D. capreolus, and 51.3% of animals were completely free of lung parasites. Testing for influencing variables, our regression models found both sex and age of the roe deer to statistically influence infestation, with male sex and younger age correlating with both stronger infestation and higher infestation rates. Accordingly, in male animals the infestation rates with V. capreoli and D. capreolus (45.1% and 20.1%, respectively) were higher than in females (39.4% and 8.0%, respectively).The overall infestation rate of juvenile animals was remarkably higher (73%) than those of sub‐adults (38.3%) or adults (28.4%).Across all age groups, infested animals showed lower body weights compared to non‐infested animals. According to our multiple linear regression model, roe deer infected with D. capreolus on average weighed 0.65 kg less than their healthy counterparts, and in the case of V. capreoli 0.72 kg less on average. While the burden on the well‐being of infested animals can only be assumed, these concrete figures (reduced body weight in infested compared to healthy animals) demonstrate the economic damage lung parasites cause to meat harvesting from bagged roe deer.