Background: Equine parvovirus‐hepatitis (EqPV‐H) research is in its infancy. Information regarding prevalence, geographical distribution, genetic diversity, pathogenesis and risk factors enhances understanding of this potentially fatal infection. Objectives: Determining the prevalence of EqPV‐H in Austrian equids. Investigating factors increasing probability of infection, liver‐associated biochemistry parameters, concurrent equine hepacivirus (EqHV) infection and phylogenetic analysis of Austrian EqPV‐H variants. Study design: Cross‐sectional study. Methods: Sera from 259 horses and 13 donkeys in Austria were analysed for anti‐EqPV‐H VP1‐specific antibodies by luciferase immunoprecipitation system (LIPS) and EqPV‐H DNA by nested polymerase chain reaction (PCR). Associations between infection status, sex and age were described. Glutamate dehydrogenase (GLDH), gamma‐glutamyl transferase (GGT), bile acids and albumin concentrations were compared between horses with active infection and PCR‐negative horses. PCR targeting partial EqPV‐H NS1 was performed and phylogenetic analysis of Austrian EqPV‐H variants was conducted. Complete coding sequences (CDS) of four Austrian variants were determined by next‐generation sequencing (NGS) and compared with published sequences. Results: Horses' EqPV‐H seroprevalence was 30.1% and DNA prevalence was 8.9%. One horse was co‐infected with EqHV. Significantly, higher probability of active EqPV‐H infection was identified in 16‐ to 31‐year‐old horses, compared with 1‐ to 8‐year‐old horses ( P = 0.002; OR = 8.19; 95% CI = 1.79 to 37.50) and 9‐ to 15‐year‐old horses ( P = 0.03; OR = 2.96; 95% CI = 1.08 to 8.17). Liver‐associated plasma parameters were not significantly different between horses with active infection and controls. Austrian EqPV‐H variants revealed high similarity to sequences worldwide. No evidence of EqPV‐H was detected in donkeys. Main limitations: Equids’ inclusion depended upon owner consent. There was only one sampling point per animal and the sample of donkeys was small. Conclusions: EqPV‐H antibodies and DNA are frequently detected in Austrian horses, without associated hepatitis in horses with active infection. The risk of active EqPV‐H infection increases with increasing age. Phylogenetic evidence supports close relation of EqPV‐H variants globally, including Austrian variants.

This pilot study aimed to investigate stable flies from Austrian pig farms for the presence of defined swine pathogens, such as porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus 2 (PCV2), hemotrophic mycoplasmas in ingested blood and/or body parts and bacteria on the surface of the flies. Furthermore, the use of stable flies as a diagnostic matrix for the detection of pathogens in the ingested pig blood should be investigated. In total, 69 different microorganisms could be found on the surface of tested S. calcitrans from 20 different pig farms. Escherichia coli was the most common bacterium and could be found on flies from seven farms. In seven farms, hemotrophic mycoplasmas were detected in stable flies. PRRSV could not be found in any of the samples of these 20 farms but PCV2 was detected in six farms. Whether the stable fly can be used as a matrix to monitor the health status cannot be accurately determined through this study, especially in regard to PRRSV. Nevertheless, it might be possible to use the stable fly as diagnostic material for defined pathogens like Mycoplasma suis and PCV2.

The diagnostic workup of respiratory disease in pigs is complex due to coinfections and non-infectious causes. The detection of pathogens associated with respiratory disease is a pivotal part of the diagnostic workup for respiratory disease. We aimed to report how frequently certain viruses and bacteria were detected in samples from pigs with respiratory symptoms in the course of routine diagnostic procedures. Altogether, 1975 routine diagnostic samples from pigs in Austrian swine stocks between 2016 and 2021 were analysed. PCR was performed to detect various pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV) (n = 921), influenza A virus (n = 479), porcine circovirus type 2 (PCV2) (n = 518), Mycoplasma (M.) hyopneumoniae (n = 713), Actinobacillus pleuropneumoniae (n = 198), Glaesserella (G.) parasuis (n = 165) and M. hyorhinis (n = 180). M. hyorhinis (55.1%) had the highest detection rate, followed by PCV2 (38.0%) and Streptococcus (S.) suis (30.6%). PRRSV was detected most frequently in a pool of lung, tonsil and tracheobronchial lymph node (36.2%). G. parasuis was isolated more frequently from samples taken after euthanasia compared to field samples. PRRSV-positive samples were more likely to be positive for PCV2 (p = 0.001), M. hyopneumoniae (p = 0.032) and Pasteurella multocida (p < 0.001). M. hyopneumoniae-positive samples were more likely to be positive for P. multocida (p < 0.001) and S. suis (p = 0.046), but less likely for M. hyorhinis (p = 0.004). In conclusion, our data provide evidence that lung samples that were positive for a primary pathogenic agent were more likely to be positive for a secondary pathogenic agent.

Prevalence studies have demonstrated a global distribution of equine hepacivirus (EqHV), a member of the family Flaviviridae. However, apart from a single case of vertical transmission, natural routes of EqHV transmission remain elusive. Many known flaviviruses are horizontally transmitted between hematophagous arthropods and vertebrate hosts. This study represents the first investigation of potential EqHV transmission by mosquitoes. More than 5000 mosquitoes were collected across Austria and analyzed for EqHV ribonucleic acid (RNA) by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Concurrently, 386 serum samples from horses in eastern Austria were analyzed for EqHV-specific antibodies by luciferase immunoprecipitation system (LIPS) and for EqHV RNA by RT-qPCR. Additionally, liver-specific biochemistry parameters were compared between EqHV RNA-positive horses and EqHV RNA-negative horses. Phylogenetic analysis was conducted in comparison to previously published sequences from various origins. No EqHV RNA was detected in mosquito pools. Serum samples yielded an EqHV antibody prevalence of 45.9% (177/386) and RNA prevalence of 4.15% (16/386). EqHV RNA-positive horses had significantly higher glutamate dehydrogenase (GLDH) levels (p = 0.013) than control horses. Phylogenetic analysis showed high similarity between nucleotide sequences of EqHV in Austrian horses and EqHV circulating in other regions. Despite frequently detected evidence of EqHV infection in Austrian horses, no viral RNA was found in mosquitoes. It is therefore unlikely that mosquitoes are vectors of this flavivirus.

The entry of BVDV into bovine cells was studied using CRIB cells (cells resistant to infection with bovine viral diarrhea virus [BVDV]) that have evolved from MDBK cells by a spontaneous loss of susceptibility to BVDV. Recently, larger genetic deletions were reported but no correlation of the affected genes and the resistance to BVDV infection could be established. The metalloprotease ADAM17 was reported as an essential attachment factor for the related classical swine fever virus (CSFV). To assess whether ADAM17 might be involved in the resistance of CRIB-1 cells to pestiviruses, we analyzed its expression in CRIB-1 and MDBK cells. While ADAM17 protein was detectable in MBDK cells, it was absent from CRIB-1 cells. No functional full-length ADAM17 mRNA could be detected in CRIB cells and genetic analysis revealed the presence of two defective alleles. Transcomplementation of functional ADAM17 derived from MDBK cells in CRIB-1 cells resulted in a nearly complete reversion of their resistance to pestiviral infection. Our results demonstrate that ADAM17 is a key cellular factor for the pestivirus resistance of CRIB-1 cells and establishes its essential role for a broader range of pestiviruses.

Background: Tick-borne encephalitis (TBE) is a zoonotic neurological disease caused by tick-borne encephalitis virus (TBEV), a flavivirus endemic in parts of Europe and Asia. Seroconversion without signs of clinical disease is common in dogs and most of the cases previously described have been tentatively diagnosed by combining neurologic signs with serum antibody titres. Here, the first Scandinavian RT-qPCR-confirmed clinical case of TBE in a dog is reported. Case presentation: A 4-year old castrated male Pointer Labrador cross was presented with acute-onset ataxia. During hospitalisation, the dog developed seizures. Despite aggressive treatment with steroids, antimicrobials and sedation/anaesthesia, there was continued deterioration during the following 24 h after admission and the dog was euthanised and submitted for necropsy. Histopathological changes in the brain were consistent with lymphoplasmacytic and histiocytic meningoencephalomyelitis. RT-qPCR examination of the brain was positive for TBEV, confirming infection. Conclusions: Meningoencephalomyelitis caused by TBEV should be a diagnostic consideration in dogs presenting with clinical signs of central nervous system disease such as acute-onset ataxia and seizures in areas where TBEV-positive ticks are endemic. Clinical TBE may be underdiagnosed in dogs due to lack of specific testing.