Emergence and expansion of roe deer (Capreolus capreolus) fibropapillomatosis in Slovakia

Twenty Years of Passive Disease Surveillance of Roe Deer (Capreolus capreolus) in Slovenia

Simple Summary

Wildlife can serve as a reservoir for highly contagious and deadly diseases, many of which are infectious to domestic animals and/or humans. Wildlife disease surveillance can be considered an essential tool to provide important information on the health status of the population and for the protection of human health. Between 2000 and 2019, examinations of 510 roe deer carcasses were conducted by comprehensive necropsy and other laboratory tests. In conclusion, the results of this research indicate a broad spectrum of roe deer diseases, but no identified disease can be considered a significant health threat to other wildlife species and/or to humans.

Abstract

In this paper, we provide an overview of the causes of death of roe deer (Capreolus capreolus) diagnosed within the national passive health surveillance of roe deer in Slovenia. From 2000 to 2019, postmortem examinations of 510 free-ranging roe deer provided by hunters were conducted at the Veterinary Faculty, Slovenia. A comprehensive necropsy was performed. According to the results of the necropsy, the samples were subjected to microscopic, histopathological, bacteriological, parasitological, or virological examination. The most frequent causes of death in roe deer were infectious diseases (67%), followed by noninfectious diseases (28%). Of all deaths, parasitic infections represented 48%, bacterial infections 14.8%, trauma 12.5%, and metabolic disorders 9.8%. Less frequent causes were diseases like neoplasia and mycotic infections, winter starvation, hernias, and lightning strike. This study covered an estimated 1% of the total disease-related mortality of roe deer in Slovenia. Comparisons of sex/age structure indicated that hunters did not provide random samples (e.g., young males were disproportionately represented). Therefore, such monitoring does not ensure an unbiased assessment of the significance of the individual disease for the mortality of the population; however, it can provide credible evidence of whether or not a particular disease is present in a population. We show that no identified disease in roe deer in Slovenia can be considered a significant health threat to roe deer, other wildlife species, or humans.

A Comprehensive Study of Cutaneous Fibropapillomatosis in Free-Ranging Roe Deer (Capreolus capreolus) and Red Deer (Cervus elaphus): from Clinical Manifestations to Whole-Genome Sequencing of Papillomaviruses

Papillomaviruses (PVs) are an extremely large group of viruses that cause skin and mucosa infections in humans and various animals. In roe deer and red deer, most PVs belong to the Deltapapillomavirus genus and cause neoplastic changes that are generally described as fibropapillomas. Despite the wide distribution of roe and red deer throughout Europe and beyond, the data in the scientific literature regarding the widespread distribution of PVs and the genetic variability of PV genomes in these species are rather scarce. This study describes cutaneous fibropapillomatosis cases in roe and red deer with clinical manifestations that are typical of infections with PVs. In all cases, the presence of PV DNA was confirmed using PCR, followed by Sanger sequencing of the partial L1 gene. The complete PV genomes were determined in all the investigated samples using next-generation sequencing technology, revealing infections of roe deer with the CcaPV1-type and red deer with the CePV1v-type variant. A comparison of the complete CcaPV1-type and CePV1v-type variant genome sequences reported here with already available complete genome sequences in GenBank revealed their great genetic stability across time and space.

Cutaneous Fibropapilloma in a Red Deer (Cervus elaphus) Associated with Cervus elaphus Papillomavirus in Portugal

A pedunculated cauliflower-like mass was detected on the left posterior limb of a subadult male red deer (Cervus elaphus) after a hunt in Portugal. Histologically the lesion was classified as cutaneous fibropapilloma. The identification of Cervus elaphus papillomavirus (CePV-1 variant) was based on sequencing of the L1 gene. The L2 sequence revealed a nine-nucleotide deletion, as already reported in the Italian and Hungarian CePV-1, further supporting the theory that this is a distinctive genomic characteristic of this viral variant, as this feature has been found in distinct cases from geographically distant countries. In addition, a coinfection with bovine papillomavirus was evidenced by amplification and sequencing of the E5 gene, confirming the ability of Delta papillomaviruses to cross-infect different animal species and providing more evidence that wildlife may act as reservoir for papillomaviruses affecting domestic species. Papillomavirus infection in red deer has been sporadically described in different European countries; in this work, we describe the identification of a CePV-1 variant infection associated with a red deer fibropapilloma in Portugal.