Two different epidemiological scenarios of border disease in the populations of Pyrenean chamois (Rupicapra p. pyrenaica) after the first disease outbreaks.

Laura Fernández-Sirera,Ignasi Marco,Santiago Lavín,Emmanuel Serrano,Cristina Riquelme,Oscar Cabezón,Alberto Allepuz,Rosa Rosell

doi:10.1371/journal.pone.0051031

Abstract

Since 2001 several outbreaks of a new disease associated with Border disease virus (BDV) infection have caused important declines in Pyrenean chamois (Rupicapra pyrenaica) populations in the Pyrenees. The goal of this study was to analyze the post-outbreak BDV epidemiology in the first two areas affected by disease with the aim to establish if the infection has become endemic. We also investigated if BDV infected wild and domestic ruminants sharing habitat with chamois. Unexpectedly, we found different epidemiological scenarios in each population. Since the disease outbreaks, some chamois populations recuperated quickly, while others did not recover as expected. In chamois from the first areas, prevalence was high (73.47%) and constant throughout the whole study period and did not differ between chamois born before and after the BDV outbreak; in all, BDV was detected by RT-PCR in six chamois. In the other areas, prevalence was lower (52.79%) and decreased during the study period; as well, prevalence was significantly lower in chamois born after the disease outbreak. No BDV were detected in this population. A comparative virus neutralisation test performed with four BDV strains and one Bovine viral diarrhoea virus (BVDV) strain showed that all the chamois had BDV-specific antibodies. Pestivirus antibodies were detected in all the rest of analyzed species, with low prevalence values in wild ruminants and moderate values in domestic ruminants. No viruses were detected in these species. These results confirm the hypothesis that outbreaks of BDV infection only affect the Pyrenean chamois, although other wild ruminants can occasionally be infected. In conclusion, two different scenarios have appeared since the first border disease outbreaks in Pyrenean chamois: on the one hand frequent BDV circulation with possible negative impact on population dynamics in some areas and on the other, lack of virus circulation and quick recovery of the chamois population.

Highlights

The Pyrenean chamois (Rupicapra pyrenaica pyrenaica) is a mountain ungulate endemic to the Pyrenees (Northern Spain, Andorra and Southern France) that belongs to the order Artiodactyla
The prevalence in animals born before or during the outbreak was 77.04% in Val d’Aran and Pallars Sobira (VAPS) and 64.43% in CAUBS, while the prevalence in chamois born after the epizooty was 61.14% in VAPS and 14.52% in CAUBS
This study focuses on the first two areas severely affected by outbreaks of Border disease virus (BDV) infection that were associated with high mortality in Pyrenean chamois

Summary

Introduction

The Pyrenean chamois (Rupicapra pyrenaica pyrenaica) is a mountain ungulate endemic to the Pyrenees (Northern Spain, Andorra and Southern France) that belongs to the order Artiodactyla. In 2001 and 2002 an outbreak of a previously unreported disease associated with BDV infection was described in Pyrenean chamois from the Central Pyrenees, in the Alt Pallars-Aran National Hunting Reserve (NHR). The population was found to have decreased by about 42%, most probably due to the disease. This was the first time that a BDV had been associated with an outbreak of a high-mortality disease in a wild species and the clinicopathological aspects were described [3]. Several disease outbreaks associated with the same virus occurred in other Pyrenean chamois populations [4]

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