Tracking the Origin of a Rabbit Haemorrhagic Virus 2 Outbreak in a Wild Rabbit Breeding Centre in Portugal; Epidemiological and Genetic InvestigationCarina L Carvalho1, Joana Rodeia2, Sandra Branco1, Madalena Monteiro3, Elsa Leclerc Duarte1, Pedro Melo4, Patricia Tavares Santos5, Ana Margarida Henriques6, Silvia Santos Barros6, Fernanda Ramos6, Teresa Fagulha6, Miguel Fevereiro6, and Margarida D Duarte6*
1Department of Veterinary Medicine, Institute of Agricultural and Environmental Sciences Mediterranean, Institute for Research and Advanced Training, University of Evora, Core Mitra, 7000 Evora, Portugal
- *Corresponding Author:
- Margarida D Duarte
National Institute for Agricultural and Veterinary Research (INIAV)
Virology Laboratory, Av. Of the Republic, Quinta do Pombal, 2780-157 Oeiras, Portugal
Tel: +351 214 767 490
Fax: +351 214403666
E-mail: [email protected]
Received date: September 20, 2016; Accepted date: October 27, 2016; Published date: November 07, 2016
Citation: Carvalho CL, Rodeia J, Branco S, Monteiro M, Duarte EL, et al. (2016) Tracking the Origin of a Rabbit Haemorrhagic Virus 2 Outbreak in a Wild Rabbit Breeding Centre in Portugal; Epidemiological and Genetic Investigation. J Emerg Infect Dis 1:114. doi:10.4172/2472-4998.1000114
Copyright: © 2016 Carvalho CL, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
As key prey, the wild rabbit downsize constitutes a major drawback on the endangered Iberian lynx (Lynx pardinus) re-introduction in the Iberia. Several captive breeding units mostly located in Alentejo, endeavour the wild rabbit repopulation of depleted areas assigned for the lynx re-introduction. Here we report an RHDV2 outbreak that occurred in early 2016 in a wild rabbit captive breeding unit located in Barrancos municipality. The estimated mortality rate between March and April 2016 was approximately 8.67%. Anatomopathologic examination was carried out for 13 victimized rabbits. Molecular characterization was based on the complete vp60 capsid gene. The 13 rabbit carcasses investigated showed typical macroscopic RHD lesions testing positive to RHDV2- RNA. Comparison of the vp60 nucleotide sequences obtained from two specimens with others publically available disclosed similarities below 98.22% with RHDV2 strains originated in the Iberia and Azores and revealed that the two identical strains from Barrancos-2016 contain six unique single synonymous nucleotide polymorphisms. In the phylogenetic analysis performed, the Barrancos-2016 strains clustered apart from other known strains, meaning they may represent new evolutionary RHDV2 lineages. No clear epidemiological link could be traced for this outbreak where the mortalities were lower compared with previous years. Yet, network analysis suggested a possible connection between the missing intermediates from which the strains from Barrancos 2013, 2014 and 2016 have derived. It is therefore possible that RHDV2 has circulated endemically in the region since 2012, with periodic epizootic occurrences. Still, six years after its emergence in wild rabbits, RHDV2 continues to pose difficulties to the establishment of natural wild rabbit populations that are crucial for the self-sustainability of the local ecosystems.