Search

Astroviruses (AstVs) are small RNA viruses characterized by a high mutation rate, the ability to recombine, and interspecies transmission, which allows them to infect a multitude of hosts including humans, companion animals, and farmed animals as well as wildlife. AstVs are stable in the environment, and their transmission is usually through the fecal–oral route or via contaminated water and food. Although direct zoonotic transmission was not confirmed, interspecies transmission events have occurred or have been indicated to occur in the past between wild and domestic animals and humans. They cause large economic losses, mainly in the poultry sector, due to gastroenteritis and mortality. In young children, they are the second most common cause of diarrhea. This study involved 166 intestine samples and pools of spleen, lymph node, and kidney samples collected from 352 wild animals, 52 pigs, and 31 companion animals. Astroviruses were detected in the intestine samples and were separately detected in pools of tissue samples prepared for individual animals using a heminested RT-PCR protocol. Amplicons were subjected to Sanger sequencing, and a phylogenetic analysis of 320 nt RNA-dependent RNA polymerase (RdRp) fragments referring to known nt sequences of astroviruses was performed. Astroviral RNA was detected in the intestine samples and/or tissue pools of red foxes (nine positive intestines and six positive tissue pools), rats (two positive intestines and three positive tissue pools), a cat (one AstV detected in an intestine sample), pigs (eight positive tissue pools), and wild boars (two positive pools of spleens, kidneys, and lymph nodes). No astroviral RNA was detected in wild mustelids, dogs, or other small wild animals including rodents. A phylogenetic analysis revealed that the astroviruses detected during this study were mostly host-specific, such as porcine, canine, and rat astroviruses that were highly homologous to the sequences of reference strains. In one of two wild boars, an AstV distinct to porcine species was found with the highest nt identity to Avastroviruses, i.e., turkey astroviruses, which suggests potential cross-species transmission of the virus, as previously described. Here, we present the first detection of astroviruses in the population of wild animals, companion animals, and pigs in Poland, confirming that astroviruses are frequent pathogens circulating in animals in the field. Our study also suggests potential cross-species transmission of Avaastrovirus to wild boars; however, further molecular characterization is needed. [ABSTRACT FROM AUTHOR]

Loss of pregnancy in mares is a major cause of economic and emotional impact for horse breeders. It can have many different infectious and noninfectious causes. The aim of this study was identification of the main viral causes of abortion in mares in Poland based on tissue samples from 180 aborted foetuses submitted for testing between 1999 and 2022. Tissues of aborted foetuses collected from different horse studs throughout Poland were tested for the presence of equine herpesvirus types 1 and 4 (EHV-1/-4) and if negative, for equine arteritis virus (EAV). The examination was performed using a PCR/reverse transcriptase PCR (1999–2012) and a quantitative PCR (2013–2022). The cause of abortion was determined to be EHV-1 in 49.4% of cases (n = 89), whereas no EHV-4- or EAV-positive cases were found. The proportion of abortions due to EHV-1 differed between regions, with the highest percentage in the Lubelskie and Wielkopolskie provinces. The results of the study indicate that EHV-1 is the most important viral infectious agent causing abortions in mares in Poland. [ABSTRACT FROM AUTHOR]

As the population size of free-living European bison in Poland has increased significantly over the last few years, conservation and management should be reconsidered to face new challenges, which aim to protect the whole population, not just individuals. The aim of our study was to analyse prevalence and identify risk factors for infections with viruses affecting reproduction (BVDV, BoHV-1, and BoHV-4), causing respiratory diseases (BRV3, BAdV-3, and BRSV), and emerging vector-borne viruses (BTV and SBV). Over 600 serum samples used in serology and 270 lung tissue samples, and 284 nasal swabs used in virological tests were collected from 24 free-living and captive European bison herds between 2016 and 2023. The seroprevalences varied between low (0.3–6.1% for BVDV, BoHV-1, and BoHV-4), medium (15.9% for BRSV and 22.1% for BTV) and high (43.3% for BRV3, 59.5% for BAdV-3, and 69.5% for SBV). Interspecies' and intraspecies' risk of endemic viral infections was observed to be density-dependent, while the effect of anthropogenic factors on the spread of infections in free-living European bison has not been demonstrated. BTV is no longer circulating, while SBV has become endemic. The higher exposure to viruses in the European bison eliminated on the basis of a veterinary decision indicates the importance of an expert supervision for disease control and prevention. [ABSTRACT FROM AUTHOR]

Many countries have reported severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infections in mink, and transmission back to humans has raised the concern of novel variants emerging in these animals. The monitoring system on Polish mink farms detected SARS-CoV-2 infection first in January 2021 and has been kept in place since then. Oral swab samples collected between February 2021 and March 2022 from 11,853 mink from 594 farms in different regions of Poland were screened molecularly for SARS-CoV-2. Isolates from those with the highest loads of viral genetic material from positive farms were sequenced and phylogenetically analysed. Serological studies were also carried out for one positive farm in order to follow the antibody response after infection. SARS-CoV-2 RNA was detected in mink on 11 farms in 8 out of 16 Polish administrative regions. Whole genome sequences were obtained for 19 SARS-CoV-2 strains from 10 out of 11 positive farms. These genomes belonged to four different variants of concern (VOC) – VOC-Gamma (20B), VOC-Delta (21J), VOC-Alpha (20I) and VOC-Omicron (21L) – and seven different Pango lineages – B.1.1.464, B.1.1.7, AY.43, AY.122, AY.126, B.1.617.2 and BA.2. One of the nucleotide and amino acid mutations specific for persistent strains found in the analysed samples was the Y453F host adaptation mutation. Serological testing of blood samples revealed a high rate of seroprevalence on the single mink farm studied. Farmed mink are highly susceptible to infection with SARS-CoV-2 of different lineages, including Omicron BA.2 VOC. As these infections were asymptomatic, mink may become an unnoticeable virus reservoir generating new variants potentially threatening human health. Therefore, real-time monitoring of mink is extremely important in the context of the One Health approach. [ABSTRACT FROM AUTHOR]

Bovine coronavirus (BCoV) is a causative agent of enteric and respiratory diseases in cattle. Despite its importance for animal health, no data is available on its prevalence in Poland. The aim of the study was to determine the virus' seroprevalence, identify risk factors of BCoV exposure in selected cattle farms and investigate the genetic variability of circulating strains. Serum and nasal swab samples were collected from 296 individuals from 51 cattle herds. Serum samples were tested with ELISA for the presence of BCoV-, bovine herpesvirus-1 (BoHV-1)- and bovine viral diarrhoea virus (BVDV)-specific antibodies. The presence of those viruses in nasal swabs was tested by real-time PCR assays. Phylogenetic analysis was performed using fragments of the BCoV S gene. Antibodies specific to BCoV were found in 215 (72.6%) animals. Seropositivity for BCoV was more frequent (P>0.05) in calves under 6 months of age, animals with respiratory signs coinfected with BoHV-1 and BVDV and increased with herd size. In the final model, age and herd size were established as risk factors for BCoV-seropositivity. Genetic material of BCoV was found in 31 (10.5%) animals. The probability of BCoV detection was the highest in medium-sized herds. Polish BCoVs showed high genetic homology (98.3–100%) and close relatedness to European strains. Infections with BCoV were more common than infections with BoHV-1 and BVDV. Bovine coronavirus exposure and shedding show age- and herd density-dependence. [ABSTRACT FROM AUTHOR]

Equine foamy virus (EFVeca) is a foamy virus of non-primate origin and among the least-studied members of this retroviral subfamily. By sequence comparison, EFVeca shows the highest similarity to bovine foamy virus. In contrast to simian, bovine or feline foamy viruses, knowledge about the epidemiology of EFVeca is still limited. Since preliminary studies suggested EFVeca infections among horses in Poland, we aimed to expand the diagnostics of EFVeca infections by developing specific diagnostic tools and apply them to investigate its prevalence. An ELISA test based on recombinant EFVeca Gag protein was developed for serological investigation, while semi-nested PCR for the detection of EFVeca DNA was established. 248 DNA and serum samples from purebred horses, livestock and saddle horses, Hucul horses and semi-feral Polish primitive horses were analyzed in this study. ELISA was standardized, and cut off value, sensitivity and specificity of the test were calculated using Receiver Operating Characteristic and Bayesian estimation. Based on the calculated cut off, 135 horses were seropositive to EFVeca Gag protein, while EFVeca proviral DNA was detected in 85 animals. The rate of infected individuals varied among the horse groups studied; this is the first report confirming the existence of EFVeca infections in horses from Poland using virus-specific tools. [ABSTRACT FROM AUTHOR]

Bats are a major global reservoir of alphacoronaviruses (alphaCoVs) and betaCoVs. Attempts to discover the causative agents of COVID-19 and SARS have revealed horseshoe bats (Rhinolophidae) to be the most probable source of the virus. We report the first detection of bat coronaviruses (BtCoVs) in insectivorous bats in Poland and highlight SARS-related coronaviruses found in Rhinolophidae bats. The study included 503 (397 oral swabs and 106 fecal) samples collected from 20 bat species. Genetically diverse BtCoVs (n = 20) of the Alpha- and Betacoronavirus genera were found in fecal samples of two bat species. SARS-related CoVs were in 18 out of 58 lesser horseshoe bat (Rhinolophus hipposideros) samples (31%, 95% CI 20.6–43.8), and alphaCoVs were in 2 out of 55 Daubenton's bat (Myotis daubentonii) samples (3.6%, 95% CI 0.6–12.3). The overall BtCoV prevalence was 4.0% (95% CI 2.6–6.1). High identity was determined for BtCoVs isolated from European M. daubentonii and R. hipposideros bats. The detection of SARS-related and alphaCoVs in Polish bats with high phylogenetic relatedness to reference BtCoVs isolated in different European countries but from the same species confirms their high host restriction. Our data elucidate the molecular epidemiology, prevalence, and geographic distribution of coronaviruses and particularly SARS-related types in the bat population. [ABSTRACT FROM AUTHOR]

Summary: A novel arbovirus, called Schmallenberg virus (SBV), emerged in Europe in 2011 infecting domestic as well as wild ruminants. The virus was first detected in Poland during the 2012 vector season. In order to study the SBV post‐epidemic period in Poland, over twenty‐one thousand domestic ruminants (cattle, sheep, goats) were tested for SBV infection between 2013 and 2018. Samples were collected as part of the national Bluetongue virus (BTV) surveillance programme. Thirteen per cent of all samples were collected from animals between 6 months and one year of age. Overall, 37.5% of ruminants tested seropositive. The seroprevalence fluctuated yearly and was highest in 2014 and 2017; however, seroconversion was detected in younger animals throughout the study indicating continuous virus circulation during the 6‐year study period. A significantly higher proportion of seropositive animals were detected among cattle and older animals. Uneven distribution of seropositive animals between provinces was identified and may be a result of different housing and breeding practices and/or meteorological conditions influencing local and regional vector abundances, rather than farm stocking densities. A small number of animals were identified as being exposed to both SBV and BTV; this is likely due to the fact that the same Culicoides species transmit these two viruses thus increasing the risk of co‐exposure. Considering these results, in addition to virological and entomological studies carried out in Poland previously, it can be concluded that SBV is endemic in Poland with cyclical waves of virus circulation happening every 3–4 years. [ABSTRACT FROM AUTHOR]

Since April 2020, when the first SARS-CoV-2 infection was reported in mink and subsequently in mink farm workers in the Netherlands, it has been confirmed that human-to-mink and mink-to-human transmission can occur. Later, SARS-CoV-2 infections in mink were reported in many European and North American countries. Samples from 590 mink from a total of 28 farms were tested by real-time RT-PCR. Whole genome sequences from one positive farm were generated and genetic relatedness was established. SARS-CoV-2 RNA was detected on a breeder farm with stock of 5,850 mink. Active viraemia was confirmed in individually tested samples with Ct values respectively between 19.4 and 29.6 for E and N gene fragments. Further testing of samples from culled animals revealed 70% positivity in throat swabs and 30% seropositivity in blood samples. Phylogenetic analysis of full-length nucleotide sequences of two SARS-CoV-2 isolates revealed that they belong to the 20B Nextstrain clade. Several nucleotide mutations were found in analysed samples compared to the reference Wuhan HU-1 strain and some of them were nonsynonymous. We report the infection of mink with SARS-CoV-2 on one farm in Poland and the results of subsequent analysis of virus sequences from two isolates. These data can be useful for assessment of the epidemiological situation of SARS-CoV-2 in Poland and how it endangers public health. [ABSTRACT FROM AUTHOR]

In this report, we describe the detection of bovine viral diarrhea virus (BVDV) contamination in commercial animal-derived sera and vaccines against animal viral pathogens on the market in Poland. Antibodies against BVDV were detected in 4/45 sera samples (8.9%) using an ELISA test. The presence of BVDV antigen was found using ELISA in 3/45 serum samples (6.6%) and 18/172 vaccine samples (10.5%). An RT -PCR was conducted using primers targeting two genome regions, the five prime untranslated region (5'UTR) and N-terminal protease (Npro). BVDV RNA was detected in 33/45 (73.3%) of sera, and 11/172 samples (6.4%) of collected vaccines, of which one vaccine did not declare BVDV strain in its composition. A single serum showed the presence of an infectious virus and only one was contaminated with all 3 species of BVDV. The most frequent species in sera was BVDV-3 (75.5%), whereas in vaccines only BVDV-1 was identified. Sequence analysis showed that the tested commercial sera and one vaccine were contaminated by six genotypes of BVDV: -1a, -1b, -1c, -1d, -2a, and -3. Identification of BVDV and its genetic material in animal-derived products is important due to the possibility of pestivirus transmission as well as the chance of falsifying the results of a diagnostic test. It also demonstrates the necessity of rigorous monitoring of the bioproducts used at the laboratory and industry level. [ABSTRACT FROM AUTHOR]

Introduction: Traditionally, evolutionary analysis of equine influenza virus (EIV) is based on the HA gene. However, the specificity of the influenza virus enables the classification of viral strains into different phylogenetic groups, depending on the gene being analysed. The aim of the study was to analyse phylogenetic paths of EIV based on M gene with reference to the HA gene. Material and Methods: M gene of Polish isolates has been sequenced and analysed along with all M sequences of EIV available in GenBank database. Phylogenetic analysis was performed using BioEdit, ClustalW, and MEGA7 softwares. Results: The clustering of the strains isolated not only from Asia but also from Europe into one common Asian-like group of EIV was observed. Twelve nucleotide substitutions in the M gene of strains from the Asian-like group were crucial for the evolutionary analysis. We also observed homology in the M gene of the Asian-like and H7N7 strains. Conclusions: M gene specific for the Asian-like group is present in strains recently isolated in Europe and Asia, which were classified previously in the Florida 2 clade based on HA. Therefore, Asian-like group does not seem to be assigned to a specific geographical region. Traces of H7N7 strains in more conservative genes like M of some contemporary EIV strains may indicate the link between the old phylogenetic group and recent H3N8 strains. Analysis of conservative genes may be more useful in tracking the direction of virus evolution than in the genes where the high variability rate may blur the original relationships. [ABSTRACT FROM AUTHOR]

The 2 predominant circulating subtypes of influenza A virus in the dog population, equine-origin H3N8 and avian-origin H3N2, constitute a potential zoonotic risk. We determined the prevalence of influenza A antibodies in 496 dogs in Poland and found 2.21% of sera positive by commercial ELISA. Hemagglutination inhibition (HI) assays indicated 7.25% of sera positive using equine H3N8, swine H3N2, and pandemic H1N1 antigens, with the most frequently detected immune response being to H3N2. Considering interspecies transfer, reassortment ability, and close contact between dogs and humans, infections of dogs with influenza A virus should be monitored. [ABSTRACT FROM AUTHOR]

Equid herpesvirus type 1 (EHV-1) is a common viral infection associated with varied clinical outcomes including respiratory disease, abortion and neurological disease. We have characterized EHV-1 sequences (n = 38) obtained from cases of equine abortion in Poland between 1999 and 2016, based on sequencing of PCR products from open reading frames (ORF) 30 and 68 of the EHV-1 genome. The majority (81.6%) of sequences were not classified into any of the previously described groups based on the ORF68 sequence. The remaining sequences belonged to ORF68 group III (7.9%) or IV (10.5%). A haplotype network analysis did not show any obvious structure within networks of local Polish sequences, nor within a global network of 215 EHV-1 sequences when these networks were coloured based on the geographical origin of viruses or date of detection. Our data suggest that ORF68 does not provide a reliable molecular marker for epidemiological studies of EHV-1, at least in a global sense. Its usefulness to aid local investigations of individual outbreaks remains to be established. All but two Polish EHV-1 sequences belonged to the ORF30 N genotype. The two ORF30 D viruses were obtained from abortion cases in 2009 and 2010. Hence, abortion cases that occurred in Poland between 1999 and 2016 were caused predominantly by EHV-1 with the ORF30 N genotype, with no indication of an increase in the prevalence of the ORF30 D variant. [ABSTRACT FROM AUTHOR]

The study was performed on nasal swabs, tracheal samples, and sera obtained from young beef heifers aged between 6 and 12 months, from farms in eastern and south-eastern Poland. The samples were evaluated using bovine herpesvirus 1 (BHV-1) ELISA kits (ELISA BHV1 antibody and ELISA BHV1 antigen) and PCR. Among all the animals examined, 37 (32.2%) were positive in the ELISA BHV1 antigen test. The presence of BHV-1 was confirmed by PCR in 42 (36.5%) animals. In the ELISA BHV1 antibody test, 39 (33.9%) seropositive animals were identified. The presence of BHV-1 positive samples was observed in all the examined breeds of young cattle. There were no significant differences (P ≤ 0.05) in BHV-1 positive samples. The results indicate that the incidence of BHV-1 infections in feedlot cattle herds studied was 32.2%-36.5%, which suggests that preventive measures should be implemented in order to limit transmission of the virus. [ABSTRACT FROM AUTHOR]

Equid herpesvirus 5 (EHV-5) is one of two γ-herpesviruses that commonly infect horses worldwide. The objective of the study was to estimate the genetic variability within EHV-5 viruses circulating among horses in Poland. Partial glycoprotein B (gB) sequences from 92 Polish horses from 13 studs throughout Poland were compared to each other and to three EHV-5 sequences from other countries. Despite the overall high level of conservation, considerable variability was observed around the putative furin cleavage site. Based on phylogenetic analysis, the viruses clustered within two major lineages (A and B), with further sub-clustering within group A. The clustering of EHV-5 sequences was independent of age or geographical origin of the sampled horses. Recombination was identified as one of the factors contributing to the genomic heterogeneity. Viruses from unweaned foals were more similar to viruses from other foals at the same stud than to viruses form their dams, suggesting the horizontal transfer and/or evolution of EHV-5 within individual hosts. Our data indicate that the gB sequence is not suitable for tracking the source of EHV-5 infection. Further research is needed to elucidate the importance of the sequence variability around the EHV-5 gB furin cleavage site on the biology of the virus. [ABSTRACT FROM AUTHOR]

Background: Astroviruses (AstVs) are common pathogens of a wide range of animal hosts, including mammals and avians, causing gastrointestinal diseases, mainly gastroenteritis and diarrhea. They prompt a significant health problem in newborns and young children and economic losses in the poultry sector and mink farms. Recent studies revealed a growing number of bat species carrying astroviruses with a noticeable prevalence and diversity. Here, we demonstrate the first detection of bat astroviruses (BtAstVs) circulating in the population of insectivorous bats in the territory of Poland. Results: Genetically diverse BtAstVs (n = 18) were found with a varying degree of bat species specificity in five out of 15 bat species in Poland previously recognized as BtAstV hosts. Astroviral RNA was found in 12 out of 98 (12.2%, 95% CI 7.1–20.2) bat intestines, six bat kidneys (6.1%, 95% CI 2.8–12.7) and two bat livers (2.0%, 95% CI 0.4–7.1). Deep sequencing of the astroviral RNA-dependent RNA polymerase (RdRp) region revealed co-infections in five single bat individuals with highly distinct astrovirus strains. Conclusions: The detection of highly distinct bat astroviruses in Polish bats favors virus recombination and the generation of novel divergent AstVs and creates a potential risk of virus transmission to domestic animals and humans in the country. These findings provide a new insight into molecular epidemiology, prevalence of astroviruses in European bat populations and the risk of interspecies transmission to other animals including humans. [ABSTRACT FROM AUTHOR]

Background: Equid herpesvirus 1 (EHV-1) infections are endemic worldwide, including Poland. Many are subclinical, but some are associated with respiratory disease, abortion, neonatal foal death, or neurological disease. We describe an outbreak of abortions in Arabian mares at a well-managed State stud farm in Poland. Case presentation: Eight of 30 pregnant mares aborted and one gave birth to a weak foal that died within 72 h after birth. EHV-1 was isolated from all fetuses as well as from the diseased foal. All viruses belonged to the N752 variant based on the predicted open reading frame (ORF) 30 amino acid sequence. All were identical to each other and to previous EHV-1 viruses from the same stud based on the ORF68 sequence analysis. The outbreak coincided with the lapse in the routine yearly EHV-1/4 vaccinations of the mares. Conclusions: Multiple abortion due to EHV-1 infection can occur in well-managed groups of horses. Reactivation of latent EHV-1 in one of the resident mares followed by a horizontal spread was considered the most likely explanation for the outbreak. Routine vaccination is an important part of a herd-heath program. [ABSTRACT FROM AUTHOR]

Background: Bats are known to host a number of nonpathogenic viruses, as well as highly pathogenic viruses causing fatal diseases like rabies. Serological surveys as part of active and passive bat rabies surveillance mainly use seroneutralization assays, demonstrating the presence of lyssavirus-specific antibodies in a variety of European bats, particularly against European bat lyssaviruses type 1 (EBLV-1). Here, we present the first serological survey in European bats of this kind during which European bats from Poland collected in the frame of passive rabies surveillance between 2012 and 2018, as well as Serotine bats (Eptesicus serotinus) and North American Big Brown bats (Eptesicus fuscus) from previous experimental studies, were tested using a commercial ELISA kit for the detection of anti-lyssavirus antibodies. Results: Lyssavirus-specific antibodies were detected in 35 (30.4%) out of 115 Polish bats of both sexes, representing nine out of 13 identified bat species endemic mainly to Central Southern Europe and Western Asia, i.e., Eptesicus serotinus, Nyctalus noctula, Myotis daubentonii, Plecotus auritus, Vespertillo murinus,Pipistrellus pipistrellus, Pipistrellus pipilstrellus/Pipistrellus pygmaeus, Myotis brandtii, and Barbastella barbastellus. Seroprevalence was highest in bat species of Nyctalus noctula, Eptesicus serotinus, Plecotus auritus, and Myotis daubentonii. More than 60% of the ELISA seropositive bats originated from the voivodeships of Silesia, Lower-Silesian, Warmian-Mazurian, and Mazowian. Rabies-specific antibodies were also found in Eptesicus fuscus bats from North America. Conclusions: The study demonstrates the principal application of the BioPro Rabies ELISA Ab Kit for the detection of anti-lyssavirus specific antibodies in body fluids and serum samples of bats. However, results may only be reliable for North American bats, whereas interpretation of results for European bats per se is difficult because proper validation of the test is hampered by the protected status of these species. [ABSTRACT FROM AUTHOR]

Susceptibility to long-term persistent infection with Equine Arteritis Virus (EAV) in stallions is related with EqCXCL16 gene alleles of the host. In our study EqCXCL16 gene alleles were determined for 63 EAV shedders and 126 non-shedders of various horse breeds. In total, 60 (31.7%) out of 189 tested stallions were identified as carriers of susceptible variants of EqCXCL16 by real time PCR and Sanger sequencing. The presence of susceptible genotype was related to horse breed with the highest percentage in Wielkopolska breed, Polish coldblood and Silesian breed horses. Strong correlation between EqCXCL16 susceptible genotypes and EAV shedding in semen (p <.0001) was observed. • Correlation between real time RT-PCR EAV positive results in semen and the presence of susceptible variants of EqCXCL16 gene was confirmed in Polish stallions. • Two methods of EqCXCL16 variant detection: real time PCR and Sanger sequencing gave similar results. • Highest percantage of susceptible EqCXCL16 variant carriers was observed in Wielkopolska breed, Polish coldblood and Silesian breed horses. • Resistant variants of EqCXCL16 gene predominated in Arabian horses, Hucul horses and Malopolska breed horses. [ABSTRACT FROM AUTHOR]

The aim of the study was to examine the effect of bovine viral diarrhoea virus (BVDV) infection on bulk tank milk somatic cell counts (BMSCC). Twenty nine dairy farms supplying milk to a dairy in Eastern Poland were recruited for the study. Bulk milk ELISA and RT-PCR were used to determine the BVDV infection status and the presence of PI animals in the farms. The BMSCC mean values for the BVDV seronegative (218.7 x 10³ cells/ml; SD: 89.8) and seropositive (214.9 x 10³ cells/ml; SD: 74.0) herds did not differ significantly. To assess the relationship between BVDV infection and BMSCC a multilevel mixed-effects linear model was used. No statistically significant effect of BVDV infection on BMSCC was found. The mean values of BMSCC for the herds with PI individuals measured before (230.1 x 10³ cells/ml, SD: 64.9) and after (223.3 x 10³ cells/ml, SD: 62.4) the PI removal were not statistically different. An increase in herd size was associated with a significant decrease in BMSCC. An increase in BMSCC was observed during summer (from May to September) compared to during winter (from October to April). [ABSTRACT FROM AUTHOR]

Equine rhinitis A (ERAV) and B (ERBV) viruses are respiratory pathogens with worldwide distribution. The current study aimed to determine the frequency of infection of ERAV and ERBV among horses and foals at Polish national studs, and to determine genetic variability within the viruses obtained. Virus-specific quantitative RT-PCR assays targeting a 5' untranslated region were used to screen nasal swabs collected from 621 horses at 16 national horse studs from throughout Poland, including 553 healthy horses and 68 horses with respiratory disease. A partial DNA polymerase gene was amplified and sequenced from the qRT-PCR-positive samples. The obtained sequences were analysed using phylogeny and genetic network analysis. None of the nasal swabs were positive for ERAV, whereas ERBV was found in 11/621 (1.78%) samples collected from 10 healthy horses and one foal affected by respiratory disease. Partial DNA polymerase gene sequence variability was correlated with individual horses and studs from which samples were collected when only Polish sequences were analysed, but there was no correlation between country of origin and ERBV sequence when Polish and international sequences were included in the network. The report presents the first detection of ERBV in Poland.

In late 2022 and early 2023, SARS-CoV-2 infections were detected on three mink farms in Poland situated within a few km from each other. Whole-genome sequencing of the viruses on two of the farms showed that they were related to a virus identified in humans in the same region 2 years before (B.1.1.307 lineage). Many mutations were found, including in the S protein typical of adaptations to the mink host. The origin of the virus remains to be determined.

Equid herpesvirus 2 (EHV-2) and 5 (EHV-5) are two γ-herpesviruses that are commonly detected from horses worldwide, based on several cross-sectional molecular surveys. Comparatively few studies examined the dynamics of γ-herpesvirus infection over time in a group of horses. The aim of the current study was to investigate the dynamics of EHV-2/5 infections among mares and their foals at three Polish national studs with different breeds of horses: Arabians, Thoroughbreds and Polish Konik horses. Nasal swabs were collected from each of 38 mare-foal pairs monthly for a period of 6 to 8 months. Virus-specific quantitative PCR assays were used to determine the viral load of EHV-2 and EHV-5 in each sample. All 76 horses sampled were positive for EHV-2 or EHV-5 on at least one sampling occasion. The majority (73/76, 96%) were infected with both EHV-2 and EHV-5. In general, the mean load of viral DNA was higher in samples from foals than from mares, but similar for EHV-2 and EHV-5 at most sampling occasions. There was, however, a considerable variability in the viral DNA load between samples collected at different times from the same foal, as well as between samples from different foals. The latter was more apparent for EHV-2 than for EHV-5. All foals became infected with both viruses early in life, before weaning, and remained positive on all, or most, subsequent samplings. The virus shedding by mares was more intermittent, indicating the existence of age-related differences. Overall, the data presented extend our knowledge of EHV-2/5 epidemiology among mares and foals.

Tick-borne encephalitis (TBE) is one of the most common zoonotic diseases in Europe transmitted by Ixodidae vectors. While small mammals such as bank voles and ticks constitute the main reservoirs for virus transmission, large sylvatic species act as a food source for ticks. Cervids such as roe deer and red deer are considered sentinel species for TBE in natural foci. In addition, an increase of the population size and density of large wild mammals in an area corresponds to an increase in the tick burden and may potentially increase the prevalence of TBE virus (TBEV) in ticks and tick hosts and further exposure risk in humans. Humans are considered accidental hosts. The prevalence of TBE relies on interactions between host, vector and environment. The present study examines the exposure of the largest European herbivore, the European bison (Bison bonasus) to TBEV infection. Assessed using the IMMUNOZYM FSME ELISA (PROGEN), the overall TBEV seroprevalence was 62.7% in the 335 European bison that were studied. ELISA results were confirmed by the gold-standard virus neutralization test (VNT) with 98.7% sensitivity and thus giving a true prevalence of 63.5%. TBEV seroprevalence was significantly correlated to the origin, age group, sex, population type (free living/captive) and sanitary status (healthy/selectively eliminated/found dead/killed in accident) of the European bison in the univariable analysis. The highest seroprevalences were observed in the three largest north-eastern wild populations (Białowieska, Borecka and Knyszyńska forests), which corresponded with the highest incidence of human cases reported in the country. The risk of TBEV seropositivity increased with age and was higher in female and free-ranging European bison. Additionally, to the epidemiological investigation, the continuous detection of TBEV antibodies was studied by repetitive testing of animals over the course of 34 months. Two of six seropositive animals remained seropositive throughout the study. The presence of antibodies was followed throughout the study in seropositive European bison and for at least a year in animals that seroconverted during the observation period., (Copyright © 2021. Published by Elsevier GmbH.)

Foamy viruses (FVs) are widely distributed and infect many animal species including non-human primates, horses, cattle, and cats. Several reports also suggest that other species can be FV hosts. Since most of such studies involved livestock or companion animals, we aimed to test blood samples from wild ruminants for the presence of FV-specific antibodies and, subsequently, genetic material. Out of 269 serum samples tested by ELISA with the bovine foamy virus (BFV) Gag and Bet antigens, 23 sera showed increased reactivity to at least one of them. High reactive sera represented 30% of bison samples and 7.5% of deer specimens. Eleven of the ELISA-positives were also strongly positive in immunoblot analyses. The peripheral blood DNA of seroreactive animals was tested by semi-nested PCR. The specific 275 bp fragment of the pol gene was amplified only in one sample collected from a red deer and the analysis of its sequence showed the highest homology for European BFV isolates. Such results may suggest the existence of a new FV reservoir in bison as well as in deer populations. Whether the origin of such infections stems from a new FV or is the result of BFV inter-species transmission remains to be clarified.

Pooled samples of female and male Culicoides midges (5146 and 332 pools, respectively) that corresponded to a total number of 124,957 specimens were collected between 2013-2017 in the vicinity of cattle barns that were distributed throughout Poland were analyzed for the presence of Schmallenberg virus (SBV) RNA. Sixty-six pools tested positive (1.2%) with mean C t value of 34.95. The maximum likelihood estimated infection rate (MLE) was calculated at 0.53 per 1000 individuals; however, it peaked in 2016 with MLE of 3.7. Viral RNA was detected in C. obsoletus/scoticus complex, C. punctatus , and C. pulicaris pools. Moreover, viral material was present in nulliparous (virgin) Culicoides females (MLE 0.27) and for the first time reported in males (MLE 0.34), which suggests the possibility of transovarial route of SBV or virus RNA transmission, as both do not fed on host blood. The accuracy of targeted versus random SBV surveillance in Culicoides vectors was compared. The relationship between infection rate (expressed as minimum infection rate; MIR), in addition to MLE, was compared with the density of virus infected midges (DIM). In conclusion, the SBV infection rate in the vector was significantly higher in 2016 as compared to other surveillance years; this is consistent with the simultaneous increase in SBV seroprevalence (seroconversion) in ruminants during the same year.

The phylogenetic analysis of influenza virus is based mainly on the variable hemagglutinin or neuraminidase genes. However, some discrete evolutionary trends might be revealed when more conservative genes are considered. We compared all available in GenBank database full length NS sequences of equine influenza virus including Polish isolates. Four nucleotides at positions A202, A237, T672 and A714 and three amino acids at positions H59, K71 and S216 which are also present in A/eq/Pulawy/2006 and A/eq/Pulawy/2008 may be discriminating for the Florida sublineage. Threonine at position 83 seems to be characteristic for EIV strains of Florida 2 isolated after 2007. There are nine common substitutions in the NS sequences of A/eq/Pulawy/2005, A/eq/Aboyne/1/2005 and A/eq/Lincolnshire/1/2006 in relation to the reference strain A/eq/Miami/63, resulting in four amino acid changes in NS1 protein (I56, E76, K140, E179) and one in NEP (R22). We grouped these strains as "Aboyne-like". Some of the listed changes were also observed in H7N7 strains isolated between 1956 and 1966, in A/eq/Jilin/89 or in pre-divergent H3N8 strains. Two hypotheses regarding the origin of this group were postulated: three independent transfers of avian influenza viruses into the equine population or reassortation between H7N7 and H3N8 EIV. Similarities of the NS sequences of "Aboyne like" viruses to viruses isolated in the fifties or seventies can reflect a phenomenon of "frozen evolution"., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: The incidence of reported cases of equine herpesvirus myeloencephalopathy (EHM) caused by infection with neuropathogenic strains of equine herpesvirus 1 (EHV-1) has markedly increased over the last decade in many Western countries. The purpose of this study was to estimate the prevalence of the neuropathogenic (G2254) and non-neuropathogenic (A2254) variants of EHV-1 among isolates associated with abortions in Polish stud farms., Results: The results of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing were consistent, and showed that two out of 64 abortions (3.1%) were induced by the neuropathogenic genotype G2254. All remaining 18 EHV-1 positive abortion cases (28.1%) were caused by the non-neuropathogenic genotype A2254., Conclusions: Most of the abortions in mares in Poland from 1999 to 2012 were associated with non-neuropathogenic strains of EHV-1. However, the presented data indicate that the neuropathogenic genotype of the virus is also present in Polish stud farms. Such a presence suggests that the future emergence of EHM in Poland is probable.

Background: In view of recurrent Schmallenberg virus (SBV) infections all over Europe between 2011 and 2013, a lively scientific debate over the importance of the sylvatic transmission cycle of the virus has emerged. The study presents results of serosurvey which included wild ruminants representing species of red deer (Cervus elaphus), roe deer (Capreolus capreolus), European bison (Bison bonasus), fallow deer (Dama dama), mouflon (Ovis orientalis musimon) hunted or immobilized at 34 different locations of Poland in the autumn/winter 2013., Results: Out of 580 sera, 145 (25%) were considered positive for SBV antibodies. The overall SBV seroprevalence calculated using district probability weights was estimated at 27.7% (95% CI: 24.0-31.4). The seroprevalences at the district level varied between 0 and 80.0% (95% CI: 24.5-135.0%) with the mean within-district prevalence of 24.0% (95% CI: 16.5-31.4). Significantly higher seroprevalence was observed in animals from the Eastern provinces (36.6%) compared to the Western provinces (22.8%). SBV infection impact varied significantly between different species (higher SBV seroprevalence in larger species such as European bison), population type (free-ranging; captive), age, body weight, percent of the district forest area, part of Poland, and the densities of wild and domestic ruminants at the district and province level. Using statistical multivariable logistic model, population type, age, part of Poland and domestic ruminant density were identified as the main risk factors for SBV infection in wild ruminants in Poland., Conclusions: SBV seroprevalence in wild ruminants, similarly to the epizootic situation in domestic ruminants in the country, varied significantly between districts and provinces. Association between SBV seropositivity, species, animal body weight and age group expressed by a higher prevalence in larger ruminants may be explained by more frequent exposure to midge-vector bites of the latter, however it might also be related to the different species susceptibility to SBV infection. The positive effect of higher domestic ruminant density on the risk of SBV infection in wildlife and lower SBV seroprevalences in the latter suggested that the sylvatic cycle of SBV transmission is an effect of the pathogen spillover from the domestic animals.

This report describes the first identification in Poland of bovine viral diarrhoea virus (BVDV)-2 in a dairy herd where severe clinical disease with losses of young animals was observed. The virus was readily cultivated in cell culture and a phylogenetic analysis of the nucleotide sequences and secondary structures of the viral genomic 5' untranslated region confirmed virus identity. The economic impact of the infection was significant compared to the previously prevalent BVDV-1 infections confirming that this genotype of BVDV can cause severe sickness in affected herds. The use of BVDV-1 vaccine did not prevent the infection with the BVDV-2 genotype., (Copyright © 2014 Elsevier Ltd. All rights reserved.)