Pseudorabies virus infection (Aujeszky’s disease) in an Iberian lynx (Lynx pardinus) in Spain: a case report

Abstract

BackgroundThe only natural hosts of Pseudorabies virus (PRV) are members of the family Suidae (Sus scrofa scrofa). In species other than suids infection is normally fatal. In these mammals, including carnivores, PRV typically causes serious neurologic disease. The endangered Iberian lynx (Lynx pardinus) is a wild feline endemic to south-western Europe (Iberian Peninsula). The Iberian lynx was found to be the world’s most endangered felid species in 2002. In wild felines, PRV infection has only been previously reported once in a Florida panther in 1994. No seropositive lynxes have ever been found, nor has PRV been detected in dead Iberian lynxes to date.Case presentationWe describe the first reported case of pseudorabies in an Iberian lynx (Lynx pardinus). Pseudorabies was diagnosed in a young wild Iberian lynx from Extremadura (SW Spain) by histopathological examination, immunohistochemistry, polymerase chain reaction (PCR) and sequence analysis. Gross lesions included alopecia of the ventral neck, bloody gastro-intestinal contents and congestion of the brain. Histopathological analysis showed a moderate nonsuppurative meningoencephalitis with diffuse areas of demyelination, necrotizing gastritis and enteritis of the small intestine. Pseudorabies virus (PRV) antigen was found in neuronal and non-neuronal cells of the brain, tonsils, and gastric glandular epithelial cells by immunohistochemical analysis. The presence of the virus in the brain was confirmed by nested PCR. The sequence analysis of the 146 bp fragment (from the viral glycoprotein B gene) showed that the amplified sequence matched (with 100% identity) the PRV genome. Furthermore, specific DNA from glycoprotein D and E encoding-genes was detected by conventional and real-time PCR, respectively, confirming the latter that this infection was produced by a wild-type PRV strain.ConclusionsThis study supports the suspicion that PRV could infect the Iberian lynx. The detection of PRV in a dead Iberian lynx suggests that the virus may have a negative impact on the survival of endangered lynxes in the wild. However, because this is the first verified instance of lynx mortality resulting from pseudorabies, its true impact on the population is unknown.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0938-7) contains supplementary material, which is available to authorized users.

First description of sarcoptic mange in the endangered Iberian lynx (Lynx pardinus): clinical and epidemiological features

“…The existence of different situations, ecological features, and health threats prevents the extrapolation of data among different populations within the same species (López et al 2014). This presence of different health threats in different populations could explain the fact that the first descriptions of two new pathogen agents for the Iberian lynx, i.e., Pseudorabies virus (detected in 2015, Masot et al 2017) and S. scabiei (detected in 2016, as shown in this work) have been reported in cubs born in the first year with confirmed reproduction in Extremadura (SW Spain) and Castilla La Mancha (Central Spain), respectively, from which the species had disappeared and was reintroduced in 2014 (LIFE10NAT/ ES/570).…”

“…Subsequent studies carried out to investigate the transmission of FeLV from affected lynxes to cats stressed the particular susceptibility of Iberian lynxes to infectious diseases (Geret et al 2011). Other infectious diseases, such as tuberculosis, pasterellosis, clostridiosis, feline parvovirus infection, or Aujeszky's disease virus infection, have been confirmed to affect the Iberian lynx (Millán et al 2009;López et al 2014;Masot et al 2017), but few works have been published with regard to the effects of macroparasites and ectoparasites on L. pardinus, including their effect as pathogens or as vectors of pathogens (Millán et al 2007). Sarcoptic mange, which is caused by the burrowing mite Sarcoptes scabiei, is a relevant illness owing to its zoonotic condition and economical relevance in domestic animals, while from an ecological point of view, sarcoptic mange may be an important problem for isolated or small size populations (Martin et al 1998;Kalema-Zikusoka et al 2002).…”

Lynx eats cat: disease risk assessment during an Iberian lynx intraguild predation

“…Under this scenario, a routine FeLV epidemiological surveillance was implemented from the very beginning of the reintroduction program in Extremadura. Since then, only one lynx was identified as FeLV-provirus positive by PCR in samples of spleen and bone marrow out of 27 lynxes sampled to date (Masot et al 2017).…”

The Role of Scavenging in Disease Dynamics

“…Cannibalism after Aujeszky's disease outbreaks (a viral disease of swine and wild boar that can affect most mammals except humans and primates) in wild boar has been related to pathogen transmission (Gortazar et al 2002), although the relevance of scavenging is punctual and short-term. Anecdotally, scavenging Aujeszky's virus infected material is a risk for carnivores, such as the Florida panther (Felis concolor corii), the European brown bear (Ursus arctos; Glass et al 1994;Zanin et al 1997) and the endangered Iberian lynx (Masot et al 2016), although without relevance for disease maintenance.…”