Wolf ( Canis lupus ) as canine adenovirus type 1 (CAdV‐1) sentinel for the endangered cantabrian brown bear ( Ursus arctos arctos )

Abstract

Canine adenovirus type 1 (CAdV‐1) causes infectious canine hepatitis (ICH) and has recently been described as a cause of death among endangered populations of European brown bear (Ursus arctos arctos) in the Cantabrian mountain range in Asturias, Spain. Sympatric wild and domestic carnivores can act as reservoirs of the virus and likely spread it into the environment and subsequently transmit it to brown bears. The present work investigates the prevalence and geo‐temporal distribution of CAdV‐1 among free‐ranging wolves (Canis lupus) in Asturias from 2009 to 2018, during which three fatal cases of ICH were reported among brown bears in the region. A total of 149 wolves were analysed in this study, of which 21 (14%) were found to have CAdV‐1 DNA based on real‐time polymerase chain reaction (RT‐PCR) of spleen samples. Prevalence of the virus was similar between males and females. All but one of the 20 CAdV‐1‐positive animals of estimable age were younger than 2 years, and only one of the 46 adult animals (>2 years) tested positive. Prevalence was highest in the western area of Asturias and during 2010 and 2011. Our results confirm that CAdV‐1 is circulating in Asturian free‐ranging wolves, supporting their possible role as virus reservoirs and sentinels in the region of this emerging disease in brown bears.

Integrated Use of Molecular Techniques to Detect and Genetically Characterise DNA Viruses in Italian Wolves (Canis lupus italicus)

“…Four out of 23 (17.4%) wolves tested positive for CAdV DNA. Two wolves tested positive to CAdV-1, supporting the possibility that the wolf may transmit CAdV-1 to other wild carnivores or domestic dogs via urine, faeces, and anal gland secretions, representing a risk for not-vaccinated animals [ 37 ]. A higher frequency of CAdV-1 infection in wolves were reported in Spain by Oleaga and colleagues (14.1%) [ 37 ] and Millán and colleagues (70.3%) [ 29 ].…”

“…Two wolves tested positive to CAdV-1, supporting the possibility that the wolf may transmit CAdV-1 to other wild carnivores or domestic dogs via urine, faeces, and anal gland secretions, representing a risk for not-vaccinated animals [ 37 ]. A higher frequency of CAdV-1 infection in wolves were reported in Spain by Oleaga and colleagues (14.1%) [ 37 ] and Millán and colleagues (70.3%) [ 29 ]. The variable frequency of infection detected can be explained by a genuine non-homogeneous spread of the virus in different geographical areas investigated, as reported for red foxes [ 67 ].…”

“…CAdV-2 has been detected in faecal samples of red foxes and wolves, but its pathogenic role in domestic dogs as well as in wild carnivores is unclear [ 33 , 34 , 35 ]. The recommended vaccination of dogs using modified live CAdV-2 confer cross-protection and has greatly reduced the circulation of CAdV-1 among domestic dogs in developed countries [ 36 ], but unvaccinated dogs in rural areas may be a source of the virus [ 37 ].…”

Canine Adenovirus 1 Isolation Bioinformatics Analysis of the Fiber

“…The haemagglutination and neutralization tests do not provide definitive differentiation between CAdV-1 and CAdV-2 isolated from the digestive tract ( Timurkan et al., 2018 ). However, PCR is a powerful tool for the differentiation of CAdV-1 and CAdV-2 ( Balboni et al., 2019 ; Oleaga et al., 2021 ). The genomic region encoding the E3 gene and flanking sequences were selected as the target for a pair of primers to diagnose and differentiate the two serotypes of CAdV ( Hu et al., 2001 ).…”

Immunogenicity of an Inactivated Canine Adenovirus Type 1 Vaccine for Foxes

“…Conversely, CAdV-2 infects respiratory tissues and induces infectious laryngotracheitis ( 3 ). CAdV-1 infects a wide range of animals, including dogs, foxes, wolves ( 4 ), mountain dogs, bears, skunks, and guinea pigs. The virus consists of a non-enveloped icosahedral virion of 80 nm in diameter that replicates in the nucleus of the host cell.…”