A screening for virus infections in eight herds of semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus) in Norway, 2013–2018

Authors: TRYLAND, MORTEN - University Of Norway; SÁNCHEZ ROMANO, JAVIER - University Of Norway; NYMO, IGENBJORG - Norwegian Veterinary Institute; BREINES, EVA - University Of Norway; ANCIN MURGUZUR, FRANCISCO - University Of Norway; KJENSTAD, OLE - University Of Norway; LI, HONG - Retired ARS Employee; Cunha, Cristina

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2021
Publication Date: 10/12/2021
Citation: Tryland, M., Sánchez Romano, J., Nymo, I.H., Breines, E.M., Ancin Murguzur, F.J., Kjenstad, O.C., Li, H., Cunha, C.W. 2021. A screening for virus infections in eight herds of semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus) in Norway, 2013–2018. Frontiers in Veterinary Science. 8. Article 707787. https://doi.org/10.3389/fvets.2021.707787.
DOI: https://doi.org/10.3389/fvets.2021.707787

Interpretive Summary: Reindeer husbandry is of major economic and cultural importance in Norway. However, little is known about the exposure of semi-domesticated reindeer to viral pathogens in southern regions of of the country, where about 67.000 reindeer are hosted. In this study, the prevalence of viral pathogens was investigated in eight different semi-domesticated reindeer herds sampled during fall and winter (October - April) in five consecutive years, during the period 2013 to 2018. A total of 618 animals were sampled live at routinely herding practices or during slaughter process. Antibodies against Cervid herpesvirus 2 and malignant catarrhal fever viruses were found in all eight herds sampled, with a total prevalence of 42 % (range 21-62 %) and 11 % (range 2-15 %), respectively. Anti-Pestivirus antibodies were detected in five of eight herds, with a total prevalence of 19 % (range 0-52 %). Antibodies against Bluetongue virus or Schmallenberg virus were not detected in any herd. Parapoxvirus-specific DNA was detected in two animals representing two different herds in Finnmark. The study establishes a reference point for exposure of semi-domesticated reindeer to viral pathogens in important herding regions in Norway. Such reference data are necessary for future studies, addressing impacts of climate change and pasture fragmentation, and the mitigation strategies conducted, such as supplementary feeding.

Technical Abstract: Background: Previous serological screenings have indicated that Eurasian semi-domesticated tundra reindeer (Rangifer tarandus tarandus) in Finnmark, Northern Norway, are exposed to alphaherpesvirus, gammaherpesvirus and pestivirus. Alphaherpesvirus (i.e., Cervid herpesvirus 2; CvHV2) has been identified as the transmissible component of infectious keratoconjunctivitis (IKC). Limited knowledge exists on the presence and prevalence of virus infections in other herding regions in Norway, which are hosting !67,000 semi-domesticated reindeer and have contact with other species and populations of wildlife and livestock than those present in Finnmark. Methods: Blood samples (n = 618) were obtained over five winter seasons (2013–2018), from eight different herds representing summer pasture districts in Tana, Lakselv, Tromsø, Lødingen, Hattfjelldal, Fosen, Røros, and Filefjell, distributed from North to South of the reindeer herding regions in Norway. Blood samples were investigated for specific antibodies against five viral pathogen groups, alphaherpesvirus, gammaherpesvirus (viruses in the malignant catarrhal fever group; MCFV), pestivirus, bluetongue virus (BTV), and Schmallenberg virus (SBV), by using commercial multispecies serological tests (ELISA). In addition, swab samples obtained from the nasal mucosal membrane from 486 reindeer were investigated by PCR for parapoxvirusspecific DNA. Results: Antibodies against aphaherpesvirus and MCFV were found in all eight herds, with a total prevalence of 42% (range 21–62%) and 11%(range 2–15%), respectively. Anti-Pestivirus antibodies were detected in five of eight herds, with a total prevalence of 19% (range 0–52%), with two of the herds having a particularly high seroprevalence. Antibodies against BTV or SBV were not detected in any of the animals. Parapoxvirus-specific DNA was detected in two animals representing two different herds in Finnmark. Conclusions: This study confirmed that alphaherpesvirus and MCFV are enzootic throughout the geographical reindeer herding regions in Norway, and that pestivirus is present in most of the herds, with varying seroprevalence. No exposure to BTV and SBV was evident. This study also indicated that semi-domesticated reindeer in Finnmark are exposed to parapoxvirus without disease outbreaks being reported from this region