Lymphoid and fetal tissue as diagnostic samples for pestivirus detection in semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus) in Norway

Introduction Serological data have indicated presence of a potentially endemic pestivirus in global reindeer populations for several decades. However, a pestivirus is yet to be detected in natural reindeer populations, and information on clinical symptoms, pathogenesis, and epidemiology is therefore lacking. Our objective was to evaluate lymphoid and fetal tissue for the detection of pestivirus from Norwegian semi-domesticated reindeer. These tissues were selected based on evidence supporting their use for pestivirus detection in other host species and the absence of confirmed detection in our previous study of reindeer ear tissue. Methods Spleen ( n = 522), intestinal lymph node ( n = 11), and fetal tissue ( n = 112) samples were collected and analyzed using reverse transcription polymerase chain reaction (RT-PCR), a commercial BVDV E rns antigen-capture ELISA (ACE), three commercial quantitative BVDV PCR (RT-qPCR), and virus isolation. Results A virus “Reindeer-508” was successfully isolated and propagated from one spleen sample. Sequencing of the 5′ untranslated region (5′UTR) and the nearly complete genome sequence consisting of 11,194 nucleotides, demonstrated closest similarity with the pronghorn antelope ( Antilocapra americana ) pestivirus ( Orthopestivirus antilocaprae) with 76.10% and 61.56% similarity, respectively. The RT-qPCR and ACE assays did not detect the novel isolate. Discussion The detection of this novel virus underscores the need for further studies to define its characteristics, distribution, prevalence, pathogenicity, tissue tropism, and effects on reindeer health and reproduction, while evaluating the adequacy of current orthopestivirus detection methods and the potential relevance for surveillance programs in Fennoscandia.