| Abstract: | The study was carried out on 70 roe deer (Capreolus capreolus) carcasses sent to our laboratory for diagnostic purposes between November 2012 and November 2013. The animals were mostly collected after car accident or found dead (n.33) in the province of Sondrio or died at a local rescue center (n.37). During routine necropsy facial and inguinal areas were examined for lice detection.
An “infestation score” was calculated (mild – medium – severe) according to the number of lice collected.
Some (1350) lice collected from the rostral part of the face area (nose and chin) were stored in 70% ethanol for species, sex and age characterization through dichotomical keys. 22 out of 70 (31%) roe deer were found visually infested by lice. Damalinia (Cervicola) meyeri, the typical louse of roe deer, is the only species of louse identified and, despite the severe dermatitis and massive infestation observed, we couldn’t find any exotic and more pathogenic species as reported for cervids in North America.
The nymphs/adult females ratio of Damalinia (Cervicola) meyeri varied from 0,13 to 4,92. Only 3 male lice were collected, from 3 different roe deer, supporting the hypothesis of parthenogenesis, as already observed in other Trichodectidae species.
According to the data analysis, a seasonal pattern both of age ratio and lice prevalence can be described. In particular a statistically significant increase of nynphs/adult female ratio can be described in spring and autumn (1,92 and 0,82 respectively) compared to summer and winter (0,38 and 0,31 respectively) (ANOVA P < 0,05) while an opposite prevalence trend can be seen in spring (25%) compared to autumn (60%), winter (50%) and summer (56%). The severity of dermatitis was positively correlated (ANOVA p< 0,01) with the nynphs/adult females ratio.
Roe deer infested also by other arthropods (Lipoptena spp., Cephenemyia spp., Ixodes spp.) demonstrated a younger population of lice (ANOVA P< 0,05).
The positive correlation between infestation score and age and gender (massive infestation in females more than ten years old, Fisher’s exact test p<0,05) suggest a hidden biotic factor that drive parasite population to rise. Furthermore, peculiar pathological state are able to interfere with the normal time budget of ungulates (i.e. resting and self grooming) and also on their home range and their intraspecific interaction, giving lice more chance to grow. However we couldn’t find any statistically significant correlation between pathological findings and infestation indices.
Based on these results we can assume that abiotic factors can influence the prevalence of lice in roe deer but more studies such as analysis on immune response or hematological parameters could help understanding the interaction between non blood sucking ectoparasites and host welfare status.
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