Occurrence of emerging ruminant viruses in goats in Poland.

Health status of Polish goat population in regard to the viral diseases remained mostly unknown. In order to determine serological status of Polish goats for selected emerging ruminant viruses, 365 serum samples collected between 2017 and 2019 in 36 districts within 10 of Polish provinces, were tested. No antibodies specific to Peste de Petite Ruminants Virus (PPRSV) and capripoxviruses (CaPV) were found in any of the tested animals. Only single individual (0.27%) was seropositive to Blutongue Virus (BTV). Antibodies directed to Schmallenberg Virus (SBV) were detected in 46 goats which represented 12.6% of the tested population. No association between seropositivity to SBV and year of sampling, province of origin, gender and age was found. In conclusion, among studied viral pathogens, currently only SBV seemed to be important for epidemiological status of Polish goats.

Serological Study of Exposure to Selected Arthropod-Borne Pathogens in European Bison (Bison bonasus) in Poland.

Bison bonasus is an indigenous species of Central and Eastern Europe with the largest wild population inhabiting Bialowieza Primeval Forest; however, free-living and captive European bison are reared in many countries around the world. Despite that the European bison was rescued from the extinction after the First World War, it remains as endangered species. Changing environment as well as human activity may have contributed to the observed increase of the risk of the emergence and re-emergence of pathogens. The aim of the survey was to establish the distribution of four pathogens transmitted by arthropods including three arboviruses [Bluetongue disease virus (BTV), Epizootic haemorrhagic disease virus (EHDV) and Schmallenberg virus (SBV)] and a bacteria (Francisella tularensis) in the main populations of European bison in Poland. A total of 251 European bison originating from eight main populations were included in the study and sampled between February 2011 and December 2014. Serum samples originated from chemically immobilized, eliminated or dead by natural causes animals. Additionally, 65 cervids from Bialowieza Forest were tested to compare the seroprevalences of other ruminants inhabiting the same environment. The antibodies to SBV and BTV were found in 76.1% and 24.7% of European bison, respectively. In autumn 2012, simultaneous emergence of SBV and BTV in European bison was observed; however, while SBV has spread in all populations scattered around the country, BTV infections were observed only in the north-eastern part of Poland, where BTV cases have been previously reported in domestic ruminants. European bison age was found to be the only significant risk factor for SBV and BTV seroprevalences; however, this association was connected to the animal size, rather than to the length of exposure. None of the animals tested positive for antibodies against EHDV or F. tularensis. SBV exposure rate of cervids was much lower (35.4%) than in European bison, while BTV seroprevalence was comparable in both groups.

Detection of Schmallenberg Virus RNA in Bull Semen in Poland.

The detection of Schmallenberg virus (SBV) in the breeding bull semen raised the question of the possibility of venereal transmission of SBV which could result in cost-intensive restrictions in the trade of bovine semen. In order to evaluate the presence of SBV RNA in bovine semen, 131 bull semen samples from four locations in Poland collected between 2013 and 2015 were analysed by RT-PCR for viral RNA. SBV RNA was detected in 5.3% of the samples. The study has revealed that application of an appropriate RNA extraction method is crucial to detect virus excretion via semen.

Post-epidemic Schmallenberg virus circulation: parallel bovine serological and Culicoides virological surveillance studies in Ireland.

BACKGROUND: Schmallenberg virus (SBV) emerged in northern-Europe in 2011 resulting in an epidemic of ruminant abortions and congenital malformations throughout the continent. In the years following the epidemic there have been reports of SBV overwintering and continued circulation in several European countries. When the population-level of immunity declines in exposed regions, re-introduction of SBV could result in further outbreaks of Schmallenberg disease. The aims of this study were to determine the SBV seroprevalence in previously exposed Irish dairy herds in 2014 and to investigate if SBV continued to circulate in these herds in the three years (2013-2015) following the Irish Schmallenberg epidemic. Whole-herd SBV serosurveillance was conducted in 26 herds before (spring) and following the 2014 vector-season (winter), and following the 2015 vector-season (winter). In spring 2014, 5,531 blood samples were collected from 4,070 cows and 1,461 heifers. In winter 2014, 2,483 blood samples were collected from 1,550 youngstock (8-10 months old) and a subsample (n = 933; 288 cows, 645 heifers) of the seronegative animals identified in the spring. Youngstock were resampled in winter 2015. Culicoides spp. were collected in 10 herds during the 2014 vector-season and analysed for SBV; a total of 138 pools (3,048 Culicoides) from 6 SBV vector species were tested for SBV RNA using real-time PCR. RESULTS: In spring 2014, animal-level seroprevalence was 62.5 % (cows = 84.7 %; heifers = 0.6 %). Within-herd seroprevalence ranged widely from 8.5 %-84.1 % in the 26 herds. In winter 2014, 22 animals (0.9 %; 10 cows, 5 heifers, 7 youngstock) originating in 17 herds (range 1-4 animals/herd) tested seropositive. In winter 2015 all youngstock, including the 7 seropositive animals in winter 2014, tested seronegative suggesting their initial positive result was due to persistence of maternal antibodies. All of the Culicoides pools examined tested negative for SBV-RNA. CONCLUSIONS: SBV appears to have recirculated at a very low level in these herds during 2013 and 2014, while there was no evidence of SBV infection in naïve youngstock during 2015. A large population of naïve animals was identified and may be at risk of infection in future years should SBV re-emerge and recirculate as it has done in continental Europe.

Association between antibody status to bovine herpesvirus 1 and quality of milk in dairy herds in Poland.

Bovine herpesvirus 1 (BoHV1) is one of the most important pathogens of cattle; however, its effect on somatic cell count and milk components is not completely understood. The aim of the current study was to examine the effect of BoHV1 infection on quality of bovine bulk tank milk (BTM). A total of 1,790 individual blood samples collected at 28 dairy farms were used to determine the BoHV1 infection status of the herds with ELISA tests. The quality parameters of milk were evaluated by instrumental methods with BTM samples collected at monthly intervals from May 2011 to May 2012. The statistical analysis was performed to study the associations between BoHV1 herd status, quality of BTM, and herd-specific parameters. The risk factors influencing bulk milk somatic cell count (BMSCC) were estimated using the multivariable mixed-effects maximum likelihood regression model. The true prevalences of BoHV1 infection at the animal and herd levels were 49.3 and 64.6%, respectively. The average BMSCC differed significantly between the herds grouped accordingly to their BoHV1 infection status. Interestingly, the highest BMSCC was observed in the vaccinated herds (240.3×10(3) cells/mL). Additionally, the BoHV1 herd status had a significant effect on the fat content of BTM. The largest herds that were investigated had a BoHV1 seroprevalence over 30%. The herd status was considerably influenced by the numbers of cows in the herds. Besides, no significant differences in total bacterial count or protein content in milk from BoHV1-infected und uninfected herds were observed. An increase in BMSCC was observed during summer compared with the winter months regardless of the BoHV1 status of the herds. In the final multivariable regression model, the main risk factors associated with BMSCC were BoHV1 herd status, the percentage of BoHV1 infected animals in a herd, the number of cows in a herd, and the season. Our study suggests that BoHV1 infection may influence BMSCC levels, which are key parameters of BTM quality and a reference for subclinical mastitis in a herd. In conclusion, BoHV1 infection may cause economic losses by decrease both of quantity and quality of milk.

Hepatitis E virus antibody prevalence in wildlife in Poland.

Hepatitis E is an important public health problem mostly in developing but occasionally also in industrialized countries. Domestic and wildlife animals are considered reservoirs of the hepatitis E virus (HEV). Since no information on the prevalence of autochthonous HEV infections in human and animal in Poland is available, the aim of the study was to investigate the HEV seroprevalence of different wildlife species as potential virus reservoirs in the country. No HEV antibodies were found in any of the sera collected from the red deer (Cervus elaphus), European bison (Bison bonasus), roe deer (Capreolus capreolus), elk (Alces alces), fallow deer (Dama dama), sika deer (Cervus nippon), Tatra chamois (Rupicapra rupicapra tatrica) or brown bear (Ursus arctos). HEV-specific antibodies were detected in 44.4% (95% CI 38.3-50.7) serum samples originated only from wild boars. The percentage of seropositive wild boars differed significantly between the provinces and was positively correlated with the wild boar density and rurality of the area. This study showed that HEV circulates among wild boar population in Poland, and this species should be considered as an important reservoir of the virus.

First report on equine herpesvirus type 4 isolation in Poland--evaluation of diagnostic tools.

Upper respiratory tract infections are still a serious problem in breeding and racing horses. The most common virological factors are EHV1 and EHV4, which are both a major cause of secondary infections. High EHV4 seroprevalence in Polish horses indicates a high transmission rate of this pathogen among horses and increases the need for proper diagnostics. The aim of this study was to develop a reliable laboratory diagnostic scheme for upper respiratory tract infections and to describe the first isolation of EHV4 in Poland. Twenty one nasal swabs collected from young horses under the age of 2 years showing clinical signs of equine rhinopneumonitis were tested with duplex PCR for simultaneous detection and differentiation between EHV1/EHV4. Positive samples were then subjected to virus isolation in Vero cells. Additionally, real-time PCR was developed which allowed viral copy numbers to be quantified and enabled defining that a DNA load below 10(3) copies per 1 ml of the sample reflected latent infection or decline of the disease. However, the sensitivity of traditional PCR proved to be sufficient in the diagnostic of the lytic infections and allowed identification of 10 EHV4 infected horses from which 3 strains were successfully isolated in cell culture. Another four EHV4 positive results were obtained by real-time PCR; but, a high Ct (threshold cycle) and a low virus DNA copy number suggested a latent infection. This report describes the first successful isolation of EHV4 from Polish horses.

Predominance of bovine viral diarrhea virus 1b and 1d subtypes during eight years of survey in Poland.

The genetic diversity of bovine viral diarrhea virus (BVDV) was determined from 65 animals persistently infected with BVDV and diagnosed between 2004 and 2011 in Poland. The samples originated from 28 herds in 12 provinces, where over 90% of the whole cattle population of Poland is reared. Phylogenetic analysis based on the fragments of two genomic regions of BVDV namely, 5'-untranslated region (5'-UTR) and N(pro) was performed. All the BVDV isolates belonged to BVDV-1 species and were further divided into four subtypes. There were 31 viruses of BVDV-1b subtype (47.6%) present in 12 herds, 24 of BVDV-1d subtype (36.9%) in 9 herds, 8 of BVDV-1f subtype (12.3%) in 5 herds and 2 BVDV-1g subtype (3.0%) in 2 herds. Neither BVDV-1a subtype, nor BVDV-2 species or any atypical bovine pestivirus were found among isolates tested. Despite increasing import of live cattle in the recent years, genetic diversity of Polish BVDV isolates was rather low.

First report of Schmallenberg virus infection in cattle and midges in Poland.

Two outbreaks of Schmallenberg virus (SBV) infection that coincided with the introduction of two bulls imported from France into two herds located in West Pomerania and Silesia provinces in Poland are described in detail. The first SBV real-time RT-PCR-positive result was obtained during routine testing of one of the imported bulls. The second bull and the affected farms were tracked by further investigation. Transmission of SBV into Polish cattle herds where the bulls were imported was confirmed by viral RNA detection in real-time RT-PCR, virus isolation followed by immunoperoxidase (IPX) staining and seroconversion. SBV RNA was detected also in Culicoides obsoletus pools caught in a trap located 5 km from one of the outbreaks. Testing nearly 900 samples collected prior to the two outbreaks from the same areas or provinces neighbouring with Germany where SBV cases had previously been detected gave negative results for the presence of SBV or specific antibodies. These cases are the first ones detected in cattle in Poland and provide evidence of recent transmission of the pathogen into the country and involvement of midge vectors.

Genetic detection and characterization of atypical bovine pestiviruses in foetal bovine sera claimed to be of Australian origin.

Two European laboratories independently detected atypical bovine pestiviral nucleic acids in three commercial batches of foetal bovine serum (FBS) that was claimed by the producers to be of Australian origin. Additional batches of FBS were obtained directly from Australia to exclude possible contamination of the Australian FBS with that of South American origin during manufacturing/packaging in European countries. RT-PCR amplification of partial 5'untranslated region and the complete N(pro) gene yielded a specific band with expected size, which was confirmed by DNA sequencing. Bayesian analysis of sequence data demonstrated a closer phylogenetic relation of the newly detected atypical bovine pestiviruses to those of South American origin, which were related to the recognized bovine pestivirus species, bovine viral diarrhoea virus. Taken together, the results indicated the presence of atypical bovine pestiviruses in the Australian FBS, and most likely in Australian Continent.

Differences in the susceptibility of dromedary and Bactrian camels to foot-and-mouth disease virus.

In this study, two sheep, eight dromedary camels and two Bactrian camels were inoculated with foot-and-mouth disease virus (FMDV) type A SAU 22/92. Five naive dromedary camels and four sheep were kept in direct or indirect contact with the inoculated camels. The inoculated sheep, which served as positive controls, displayed typical moderate clinical signs of FMD and developed viraemia and high antibody titres. The presence of the virus was also detected in probang and mouth-swab samples for several days after inoculation. In contrast, the inoculated dromedary camels were not susceptible to FMDV type A infection. None of them showed clinical signs of FMD or developed viraemia or specific anti-FMDV antibodies despite the high dose of virus inoculated. All the contact sheep and contact dromedaries that were kept together with the inoculated camels remained virus-negative and did not seroconvert when tested up to 28 days post-inoculation (p.i.). In comparison with the non-susceptible dromedaries, the two inoculated Bactrian camels showed moderate to severe clinical signs of FMD; however, the clinical signs of FMD appeared rather late, between 8 and 14 days p.i., compared to the inoculated sheep. Characteristic FMD lesions in the Bactrian camels, accompanied with severe lameness, were only observed on the hind feet. The presence of the virus in the serum samples of both Bactrian camels was detected by real-time RT-PCR in one of the animals on days 3 and 7 p.i. and in the second animal from days 1 to 3 p.i. and subsequently again on day 21 p.i. The Bactrian camels developed high titres of antibodies to the inoculated FMDV which appeared at 7-10 days p.i. and lasted up to 130 days p.i. Only low and transient amounts of FMDV were detected in the mouth-swab and probang samples collected from both Bactrian camels.