A picture of trends in Aujeszky's disease virus exposure in wild boar in the Swiss and European contexts

Pseudorabies virus VHS protein abrogates interferon responses by blocking NF-κB and IRF3 nuclear translocation

Herpesviruses antagonize host antiviral responses through a myriad of molecular strategies culminating in the death of the host cells. Pseudorabies virus (PRV) is a significant veterinary pathogen in pigs, causing neurological sequalae that ultimately lead to the animal's demise. PRV is known to trigger apoptotic cell death during the late stages of infection. The virion host shutdown protein (VHS) encoded by UL41 plays a crucial role in the PRV infection process. In this study, we demonstrate that UL41 inhibits PRV-induced activation of inflammatory cytokine and negatively regulates the cGAS-STING-mediated antiviral activity by targeting IRF3, thereby inhibiting the translocation and phosphorylation of IRF3. Notably, mutating the conserved amino acid sites (E192, D194, and D195) in the RNase domain of UL41 or knocking down UL41 inhibits the immune evasion of PRV, suggesting that UL41 may play a crucial role in PRV's evasion of the host immune response during infection. These results enhance our understanding of how PRV structural proteins assist the virus in evading the host immune response.

Sex-based differences in the distribution of Aujeszky's disease-seropositive Japanese wild boar

BACKGROUND

Aujeszky's disease virus (ADV) primarily infects domestic pigs and wild boars, causing the abortion and death of young piglets due to central nervous system disorders. In Japan, the national eradication program for ADV in domestic pigs has been successful in most prefectures; however, concern has been raised regarding ADV-infected wild boars as a source of transmission to domestic pigs.

RESULTS

We assessed the nationwide seroprevalence of ADV among wild boars (Sus scrofa) in Japan. Moreover, we determined the sex-based differences in the spatial clustering of seropositive animals. Serum samples were obtained from a total of 1383 wild boars acquired by hunting in 41 prefectures in three fiscal years (April-March in 2014, 2015, and 2017). Seropositivity tests for ADV using enzyme-linked immunosorbent assay, the latex agglutination and neutralization tests showed 29 boars seropositive for ADV (29/1383, 2.1% [95% confidence interval, CI: 1.4-3.0%]), with 28 of these boars originating from three prefectures in the Kii Peninsula (28/121, 23.1% [95% CI: 16.0-31.7%]). The degree of spatial clustering of these ADV-seropositive adult boars in the Kii Peninsula was evaluated using the K-function and data from sera samples of 46 (14 seropositive) male and 54 (12 seropositive) female boars. The degree of clustering among females was significantly higher in seropositive animals than in tested animals; however, such a difference was not observed for seropositive males.

CONCLUSIONS

The spatial dynamics of ADV among adult wild boars may be characterized based on sex, and is likely due to sex-based differences in behavioral patterns including dispersal among wild boars.

Epidemiology of Aujeszky disease in wild boars (Sus scrofa L.) in Croatia

Aujeszky disease (AD) or pseudorabies is a viral disease of domestic and wild animals caused by the Suid alphaherpesvirus 1. In wild boar infection usually undergo latent phase but under certain conditions reactivation of the virus can result in a disease. Seroprevalence in wild boars ranges from 0.8 to 100%, and is among other influenced by region, type of management, age and sex of the studied animals. In this study we analyzed blood, lungs, olfactory bulbs and spleen from 222 free-living wild boars from different localities in Croatia and compared results obtained by ELISA with PCR, sex, age and locality. Total seroprevalence was 33.78%, ranging from 25.26% in males to 40.15% in females (p = 0.0346; χ2 = 4.47). According to the age categories prevalence was 10% in offspring, 27.53% in subadults, and 66.75% in adults. Seroprevalence in adult males (66.66%) and females (65.30%) was almost identical. In males, significantly lower seroprevalence was detected in offspring compared to subadults (χ2 = 4.07, p < 0.05) and adults (χ2 = 31.04; p < 0.05), and in subadults compared to adults (χ2 = 15.13; p < 0.0001). Among females, adults had a significantly higher prevalence compared to offspring (χ2 = 19.27; p < 0.0001) and subadults (χ2 = 8.62; p < 0.01). Analysis between counties revealed Sisačko-moslavačka county as a hot-spot for AD. None of the samples was positive for ADV antigens. The observed trend in prevalence points to the fact that the main transmission occurs during one part of the year (most probably the mating season). Also, triggers for virus reactivation might be more complex than previously thought, since none of our samples, collected during the mating and hunting season, was PCR positive. Finally, we can conclude that adult males represent the main transmission link between different wild boar groups.

Suid alphaherpesvirus 1 of wild boar origin as a recent source of Aujeszky's disease in carnivores in Germany

BACKGROUND

The high susceptibility of carnivores to Suid Alphaherpesvirus 1 [SuAHV1, synonymous pseudorabies virus (PrV)], renders them inadvertent sentinels for the possible occurrence of Aujeszky's disease (AD) in domestic and wild swine populations. The aim of this study was to epidemiologically analyse the occurrence of PrV infections in domestic and wild animals in Germany during the last three decades and to genetically characterise the causative PrV isolates.

METHODS

PrV in dogs was detected using standard virological techniques including conventional and real time PCR, virus isolation or by immunohistochemistry. Available PrV isolates were characterized by partial sequencing of the open gC reading frame and the genetic traits were compared with those of archived PrV isolates from carnivores and domestic pigs from Germany before the elimination of AD in the domestic pig population.

RESULTS

During 1995 and 2022, a total of 38 cases of AD in carnivores, e.g. dogs and red foxes, were laboratory confirmed. Sequencing and subsequent phylogenetic analysis of PrV isolates established a strong connection between AD cases in carnivores and the occurrence of PrV infections in European wild boars in the end phase of and after elimination of AD from the domestic pig population. While PrV infections occur at low numbers but regularly in hunting dogs, interestingly, PrV was not observed in grey wolves in Germany. In none of 682 dead-found grey wolves and wolf-dog hybrids tested from Germany during 2006-2022 could PrV infection be detected by molecular means.

CONCLUSIONS

Although PrV has been eliminated from domestic pigs, spillover infections in domestic and wild carnivores should always be expected given the endemic presence of PrV in wild pig populations. Since detection of PrV DNA and virus in carnivores is sporadic even in areas with high seroprevalence of PrV in wild pigs, it may not reflect the full diversity of PrV.

The Epidemiology and Variation in Pseudorabies Virus: A Continuing Challenge to Pigs and Humans

Pseudorabies virus (PRV) can infect most mammals and is well known for causing substantial economic losses in the pig industry. In addition to pigs, PRV infection usually leads to severe itching, central nervous system dysfunction, and 100% mortality in its non-natural hosts. It should be noted that increasing human cases of PRV infection have been reported in China since 2017, and these patients have generally suffered from nervous system damage and even death. Here, we reviewed the current prevalence and variation in PRV worldwide as well as the PRV-caused infections in animals and humans, and briefly summarized the vaccines and diagnostic methods used for pseudorabies control. Most countries, including China, have control programs in place for pseudorabies in domestic pigs, and thus, the disease is on the decline; however, PRV is still globally epizootic and an important pathogen for pigs. In countries where pseudorabies in domestic pigs have already been eliminated, the risk of PRV transmission by infected wild animals should be estimated and prevented. As a member of the alphaherpesviruses, PRV showed protein-coding variation that was relatively higher than that of herpes simplex virus-1 (HSV-1) and varicella-zoster virus (VZV), and its evolution was mainly contributed to by the frequent recombination observed between different genotypes or within the clade. Recombination events have promoted the generation of new variants, such as the variant strains resulting in the outbreak of pseudorabies in pigs in China, 2011. There have been 25 cases of PRV infections in humans reported in China since 2017, and they were considered to be infected by PRV variant strains. Although PRV infections have been sporadically reported in humans, their causal association remains to be determined. This review provided the latest epidemiological information on PRV for the better understanding, prevention, and treatment of pseudorabies.

Phospho-proteomics identifies a critical role of ATF2 in pseudorabies virus replication

Pseudorabies virus (PRV), an etiological agent of pseudorabies in livestock, has negatively affected the porcine industry all over the world. Epithelial cells are reported as the first site of PRV infection. However, the role of host proteins and its related signaling pathways in PRV replication is largely unclear. In this study, we performed a quantitative phosphoproteomics screening on PRV-infected porcine kidney (PK-15) epithelial cells. Totally 5723 phosphopeptides, corresponding to 2180 proteins, were obtained, and the phosphorylated states of 810 proteins were significantly different in PRV-infected cells compared with mock-infected cells (P ​< ​0.05). GO and KEGG analysis revealed that these differentially expressed phosphorylated proteins were predominantly related to RNA transport and MAPK signaling pathways. Further functional studies of NF-κB, transcription activator factor-2 (ATF2), MAX and SOS genes in MAPK signaling pathway were analyzed using RNA interference (RNAi) knockdown. It showed that only ATF2-knockdown reduces both PRV titer and viral genome copy number. JNK pathway inhibition and CRISPR/Cas9 gene knockout showed that ATF2 was required for the effective replication of PRV, especially during the biogenesis of viral genome DNA. Subsequently, by overexpression of the ATF2 gene and point mutation of the amino acid positions 69/71 of ATF2, it was further demonstrated that the phosphorylation of ATF2 promoted PRV replication. These findings suggest that ATF2 may provide potential therapeutic target for inhibiting PRV infection.

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Phosphoproteomic profiling of PRV-infected PK-15 ​cells with iTRAQ-quantification.

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JNK pathway regulates ATF2 phosphorylation and PRV replication.

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Phosphorylation of ATF2 promotes PRV replication.

Pseudorabies virus tegument protein UL13 recruits RNF5 to inhibit STING-mediated antiviral immunity

Pseudorabies virus (PRV) has evolved various immune evasion mechanisms that target host antiviral immune responses. However, it is unclear whether and how PRV encoded proteins modulate the cGAS-STING axis for immune evasion. Here, we show that PRV tegument protein UL13 inhibits STING-mediated antiviral signaling via regulation of STING stability. Mechanistically, UL13 interacts with the CDN domain of STING and recruits the E3 ligase RING-finger protein 5 (RNF5) to promote K27-/K29-linked ubiquitination and degradation of STING. Consequently, deficiency of RNF5 enhances host antiviral immune responses triggered by PRV infection. In addition, mutant PRV lacking UL13 impaired in antagonism of STING-mediated production of type I IFNs and shows attenuated pathogenicity in mice. Our findings suggest that PRV UL13 functions as an antagonist of IFN signaling via a novel mechanism by targeting STING to persistently evade host antiviral responses.

Induction of type I interferons mediated by cGAS-STING axis is critical for host against DNA virus infection whereas herpesviruses employ multiple strategies to antagonize this signaling pathway for immune evasion. Herein, our findings provide strong evidence that PRV tegument protein UL13 functions as a suppressor of STING-mediated antiviral response via recruitment of E3 ligase RNF5 to induce K27-/K29-linked ubiquitination and degradation of STING. Therefore, our study reveals a novel evasion strategy of PRV against host defense and suggests UL13 could be a promising target for development of gene-deleted vaccine for pseudorabies.

Porcine Circoviruses and Herpesviruses Are Prevalent in an Austrian Game Population

During the annual hunt in a privately owned Austrian game population in fall 2019 and 2020, 64 red deer (Cervus elaphus), 5 fallow deer (Dama dama), 6 mouflon (Ovis gmelini musimon), and 95 wild boars (Sus scrofa) were shot and sampled for PCR testing. Pools of spleen, lung, and tonsillar swabs were screened for specific nucleic acids of porcine circoviruses. Wild ruminants were additionally tested for herpesviruses and pestiviruses, and wild boars were screened for pseudorabies virus (PrV) and porcine lymphotropic herpesviruses (PLHV-1-3). PCV2 was detectable in 5% (3 of 64) of red deer and 75% (71 of 95) of wild boar samples. In addition, 24 wild boar samples (25%) but none of the ruminants tested positive for PCV3 specific nucleic acids. Herpesviruses were detected in 15 (20%) ruminant samples. Sequence analyses showed the closest relationships to fallow deer herpesvirus and elk gammaherpesvirus. In wild boars, PLHV-1 was detectable in 10 (11%), PLHV-2 in 44 (46%), and PLHV-3 in 66 (69%) of animals, including 36 double and 3 triple infections. No pestiviruses were detectable in any ruminant samples, and all wild boar samples were negative in PrV-PCR. Our data demonstrate a high prevalence of PCV2 and PLHVs in an Austrian game population, confirm the presence of PCV3 in Austrian wild boars, and indicate a low risk of spillover of notifiable animal diseases into the domestic animal population.

Aujeszky's disease in hunting dogs after the ingestion of wild boar raw meat in Sicily (Italy): clinical, diagnostic and phylogenetic features

Background

Aujeszky's disease is caused by Suid Herpes Virus-1 and species belonging to the genus Sus scrofa are the main reservoir hosts. This virus, however, is capable of infecting and causing severe disease, with an almost constant fatal outcome in other species, both domestic and wild (carnivores, monogastric herbivores and ruminants). Moreover, the possibility of transmission to humans has been demonstrated. This study reports and describes the clinical, diagnostic, pathological and phylogenetic aspects of two cases of Aujeszky's disease in two hunting dogs following the ingestion of infected wild boar raw meat. These cases are contextualized in the province of Messina (Sicily), where a high prevalence of Aujeszky's disease has been recorded (average of 12,20% in the period 2010–2019) in farmed pig, and with evidence of spread to other species. A severe outbreak in cattle has recently been reported in these areas. Nevertheless, cases of Aujeszky's disease in dogs are rarely reported and this study represents the first well-documented report in this species in Sicily.

Case presentation

After a wild boar hunt, two dogs showed neurological symptoms and intense itching unresponsive to therapy. Diagnosis of Aujeszky's disease was made based on clinical suspicion, anamnestic information and confirmed by the isolation of the virus from the brain of both dogs. In addition, molecular typing, sequencing and phylogenetic analysis of the Real-Time PCR products were performed. The sequences studied were placed in the Italian Clade 1 along with the sequences obtained from wild boars and hunting dogs from Italy and France.

Conclusions

The finding of this disease in non-natural hosts in Sicilian multi-host epidemiological contexts suggests that the risk of inter-species transmission is concrete and that attention should be paid to developing disease control programs in these territories. The data obtained from genome sequencing of the two SuHV-1 isolates contribute to the enrichment of the GenBank with unknown sequences and the phylogenetic analysis implementation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03138-2.

Aujeszky's Disease in South-Italian Wild Boars (Sus scrofa): A Serological Survey

Simple Summary

Aujeszky’s disease (AD, pseudorabies) is a viral disease of suids caused by Suid Herpesvirus 1 (SHV-1) also referred as Aujeszky’s disease virus (ADV) or Pseudorabies virus (PRV). The aim of our study was to evaluate seroprevalence of AD in wild boar hunted in the Campania Region, during the 2016–2017 hunting season. A total of 503 serum samples from wild boars hunted in the provinces of Campania Region were tested for antibody against ADV using an ELISA assay. A Seroprevalence of 23.85% (120/503, 95% Confidence Interval (CI 95%: 20.15–27.55) was found. Gender was not significantly associated with of ADV seropositivity (p > 0.05), while the presence of ADV antibodies was statistically associated with age (>36-month, p < 0.0001) and location (Avellino, p = 0.0161).

Abstract

Aujeszky’s disease (AD, pseudorabies) is a viral disease of suids caused by Suid Herpesvirus 1 (SHV-1) also referred as Aujeszky’s disease virus (ADV) or Pseudorabies virus (ADV). Domestic pig and Wild boar (Sus scrofa) are the natural host, but many species can be infected with ADV. The aim of our study was to evaluate seroprevalence of AD in wild boar hunted in the Campania Region, during the 2016–2017 hunting season. A total of 503 serum samples from wild boars hunted in the provinces of Campania Region (Southern Italy) were collected and were tested for antibody against ADV using an AD, blocking ELISA assay. A Seroprevalence of 23.85% (120/503, 95% Confidence Interval (CI): 20.15–27.55) was found. Gender was not significantly associated with of ADV seropositivity (p > 0.05), while the presence of ADV antibodies was statistically associated with age (>36-month, p < 0.0001) and location (Avellino, p = 0.0161). Our prevalence values are like those obtained in 2010 in our laboratory (30.7%), demonstrating a constant circulation of ADV in the area.

Health status of free-ranging pure and cross-mixed miniature swine population from Northeast Spain

BACKGROUND

Miniature pigs have gained popularity as companion animals in the recent years in Spain. Due to the fact that their abandonment and crossing breeds with wild boars can cause severe problems, investigation about the health status is needed.

OBJECTIVES

The aim of this study was to determine their health status according to the clinical findings during physical examination and the results of antibody serology tests against selected infectious diseases.

METHODS

Two-hundred and eleven miniature pigs (Sus scrofa) were included in the study. Their origin, age, sex, housing conditions and diet were recorded.

RESULTS

The housing of the animals ranged from wild animals to ones living in animal sanctuaries. The diet varied from a natural one in the wild to commercial and homemade food. Thirty animals out of two-hundred and eleven were hybrids between miniature pigs and wild boars according to morphological characteristics. Antibody serology techniques of Influenza A virus, Hepatitis E virus, brucellosis, tuberculosis, African swine fever, Classical swine fever and Aujeszky's disease was performed. The prevalence for Influenza A was 5.30%, for Hepatitis E was 5.35% and the rest tested negative. It is important to control and monitor these zoonotic infections to prevent Public Health problems.

CONCLUSIONS

The results obtained from this investigation demonstrated that the animals' health status in this study is optimal and the diseases prevalence is similar or minor when compared to previous studies. This study confirms the hybridization of miniature pig and wild boar in Catalonia.

Inactivated vaccine against Aujeszky's disease

BACKGROUND AND AIM

The Aujeszky's disease, also known as Pseudorabies, remains one of the most problematic fulminant diseases in domestic animals, affecting the central nervous system. The study aimed to investigate the effect of an inactivated vaccine against Aujeszky's disease based on "Kordai" virus strain.

MATERIALS AND METHODS

To test the inactivation of the "Kordai" strain (grown by the roller method in VNK-21/13 cell culture with an infectious titer of at least 7.5 lg TCD50/ml) which is causative of Aujeszky's disease, next-generation teotropin and propolis preparations were usedin concentrations of 0.1%, 0.08%, and 0.04%.

RESULTS

As a result of comparative studies on the optimization of parameters for inactivating the "Kordai" virus strain, it was established that teotropin is a more effective inactivant than propolis. At the same time, the optimal final concentration of teotropin for inactivation was 0.1%, along with a reaction medium temperature of 37°C, pH of 7.4-7.6, and duration of inactivation of 14 h. The titer of virus-neutralizing activity (VNA) of antibodies at the pH (neutralization reactions) in vaccinated sheep of 10-12 months of age was 7.5±0.3, Ig TCID50/ml (tissue culture infectious dose 50%), and 3.5±0.3 in the cell culture VNK-21/13 (culture of Syrian hamster kidney cells).

CONCLUSION

To determine colostral immunity in newborn lambs, the method of metabolic status correction was used to vaccinate lambs obtained from immune sheep 4 months after birth. The results showed that lambs obtained from immune sheep had high VNA titers. A sustained immune response in vaccinated animals was obtained after double vaccination.

Retrieving Historical Cases of Aujeszky's Disease in Sicily (Italy): Report of a Natural Outbreak Affecting Sheep, Goats, Dogs, Cats and Foxes and Considerations on Critical Issues and Perspectives in Light of the Recent EU Regulation 429/2016

Aujeszky’s disease is caused by Suid alphaherpesvirus 1, and its main reservoir host is the pig. However, other species are also susceptible. Infection with this virus causes a severe neurological clinical picture named Aujeszky’s disease, usually accompanied by itching and death a few days after the onset of symptoms. This study reports a multi-species outbreak of Aujeszky’s disease that occurred in Sicily, which led to the death of 2 goats, 15 sheep, 2 dogs, 2 cats and 2 foxes. The diagnosis was made by culture, indirect immunofluorescence on brain samples and confirmed by biological test on rabbits. This study reports the first cases of Aujeszky’s disease in Italy in cats, goat and sheep. The finding of Aujeszky’s disease in several species in Sicily suggests a potential epizootic risk. In such areas where a multi-host system is recognised, an analysis of the risk factors should be carried out in order to develop targeted strategies for the control and eradication of the disease. The critical issues that hinder the control of Aujeszky’s disease in the studied territory and perspectives for eradication in the light of EU regulation 429/2016 are also discussed.

AUJESZKY'S DISEASE IN HUNTED WILD BOAR (SUS SCROFA) IN THE IBERIAN PENINSULA

Aujeszky's disease (AD, pseudorabies) eradication programs in domestic pigs are implemented in several European countries where AD virus (ADV) circulates in local wild boar (Sus scrofa), making studies on ADV infection dynamics in wild boar increasingly relevant. The objective of our study was to characterize ADV dynamics in wild boar at a site in central Portugal and compare this site to three enzootic sites in central Spain. A total of 235 wild boar were sampled during the hunting season 2014-15. We collected serum, tissues (oropharyngeal tonsils and trigeminal and sacral ganglia), and swabs (oral, nasal, and genital) and analyzed these samples to detect ADV antibodies (enzyme-linked immunosorbent assay) and DNA (PCR). An overall seroprevalence of 42.6% was found (range 12.7-57.7%), being highest in adults (54.1%; 72/133). Overall, 2.8% (3/108) oral, 6.4% (7/109) nasal, and 12.8% (12/94) genital swabs were PCR positive. We found 20.4% (20/98) of the wild boar had at least one positive swab and were considered shedders. We found ADV in tissues of five animals; of 111 tonsils, three (2.7%) were PCR positive. Trigeminal (2/48; 4%) and sacral (2/53; 4%) ganglia collected in central Portugal, pertaining to three animals, were positive for ADV DNA. Logistic regression models showed that seroprevalence was influenced by site and age, whereas ADV shedding was influenced by site. Our study describes patterns of ADV infection in wild boar in Portugal and shows that wild boar also pose a risk, albeit lower than that in central Spain, for the eradication of AD from extensively managed domestic pigs in Portugal.

Foodborne Zoonoses Common in Hunted Wild Boars

The northern European wild boar population has increased during the last decade. Highest wild boar numbers in Finland have been reported in the southeastern part near the Russian border. Wild boars may be infected with several human and animal pathogens. In this study, we investigated the presence of important foodborne pathogens in wild boars hunted in 2016 in Finland using serology, PCR and culturing. Seroprevalence of Salmonella (38%) and Yersinia (56%) infections was high in wild boars. Antibodies to hepatitis E virus, Toxoplasma gondii and Brucella were found in 18%, 9% and 9% of the wild boars, respectively. Trichinella antibodies were detected in 1% of the animals. We recorded no differences in the seroprevalence between males and females. However, Yersinia and T. gondii antibodies were detected significantly more often in adults than in young individuals. Listeria monocytogenes (48%) and stx-positive Escherichia coli (33%) determinants were frequently detected in the visceral organs (spleen and kidneys) by PCR. Yersinia pseudotuberculosis O:1 and L. monocytogenes 2a and 4b were identified by culturing from the PCR-positive samples. Brucella suis biovar 2 was isolated from visceral organs. No African swine fever, classical swine fever or Aujeszky's disease were detected in the wild boars. Our study shows that wild boars are important reservoirs of foodborne pathogens.

First Report of a Severe Outbreak of Aujeszky's Disease in Cattle in Sicily (Italy)

Aujeszky’s disease in cattle is caused by Suid herpes virus 1. The natural infection has been reported worldwide in bovine species and it is related to direct and indirect contact with infected pigs, which represent the main reservoir of the virus. Here, it is reported the first documented outbreak of Aujeszky’s disease in cattle in Sicily (Italy). Severe itching and nonspecific neurological symptoms were the main reported clinical signs. No characteristic gross and histological features were reported other than cutaneous lesions caused by excessive pruritus and hyperaemia, haemorrhages and inflammation in the central nervous system. Diagnosis was confirmed by real time PCR and immunohistochemistry on the nervous tissue. The route of infection remained unknown, but serological data observed in pigs living in close cohabitation with cattle revealed a circulation of a wild strain of the virus in the area. This study contributes to a better knowledge of this disease in a non-conventional host and suggests the need to increase the prophylaxis control plans in specific breeding contexts.

Monitoring of Pseudorabies in Wild Boar of Germany-A Spatiotemporal Analysis

To evaluate recent developments regarding the epidemiological situation of pseudorabies virus (PRV) infections in wild boar populations in Germany, nationwide serological monitoring was conducted between 2010 and 2015. During this period, a total of 108,748 sera from wild boars were tested for the presence of PRV-specific antibodies using commercial enzyme-linked immunosorbent assays. The overall PRV seroprevalence was estimated at 12.09% for Germany. A significant increase in seroprevalence was observed in recent years indicating both a further spatial spread and strong disease dynamics. For spatiotemporal analysis, data from 1985 to 2009 from previous studies were incorporated. The analysis revealed that PRV infections in wild boar were endemic in all German federal states; the affected area covers at least 48.5% of the German territory. There were marked differences in seroprevalence at district levels as well as in the relative risk (RR) of infection of wild boar throughout Germany. We identified several smaller clusters and one large region, where the RR was two to four times higher as compared to the remaining areas under investigation. Based on the present monitoring intensity and outcome, we provide recommendations with respect to future monitoring efforts concerning PRV infections in wild boar in Germany.

Harmonizing methods for wildlife abundance estimation and pathogen detection in Europe-a questionnaire survey on three selected host-pathogen combinations

Background

The need for wildlife health surveillance as part of disease control in wildlife, domestic animals and humans on the global level is widely recognized. However, the objectives, methods and intensity of existing wildlife health surveillance programs vary greatly among European countries, resulting in a patchwork of data that are difficult to merge and compare. This survey aimed at evaluating the need and potential for data harmonization in wildlife health in Europe. The specific objective was to collect information on methods currently used to estimate host abundance and pathogen prevalence. Questionnaires were designed to gather detailed information for three host-pathogen combinations: (1) wild boar and Aujeszky’s disease virus, (2) red fox and Echinococcus multilocularis, and (3) common vole and Francisella tularensis.

Results

We received a total of 70 responses from 19 European countries. Regarding host abundance, hunting bags are currently the most widely accessible data source for widely distributed mid-sized and larger mammals such as red fox and wild boar, but we observed large differences in hunting strategies among countries as well as among different regions within countries. For small rodents, trapping is the method of choice, but practical applications vary among study sites. Laboratory procedures are already largely harmonized but information on the sampled animals is not systematically collected.

Conclusions

The answers revealed that a large amount of information is available for the selected host-pathogen pairs and that in theory methods are already largely harmonized. However, the comparability of the data remains strongly compromised by local differences in the way, the methods are applied in practice. While these issues may easily be overcome for prevalence estimation, there is an urgent need to develop tools for the routine collection of host abundance data in a harmonized way. Wildlife health experts are encouraged to apply the harmonized APHAEA protocols in epidemiological studies in wildlife and to increase cooperation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0935-x) contains supplementary material, which is available to authorized users.

Pseudorabies virus infection (Aujeszky's disease) in an Iberian lynx (Lynx pardinus) in Spain: a case report

Background

The only natural hosts of Pseudorabies virus (PRV) are members of the family Suidae (Sus scrofa scrofa). In species other than suids infection is normally fatal. In these mammals, including carnivores, PRV typically causes serious neurologic disease. The endangered Iberian lynx (Lynx pardinus) is a wild feline endemic to south-western Europe (Iberian Peninsula). The Iberian lynx was found to be the world’s most endangered felid species in 2002. In wild felines, PRV infection has only been previously reported once in a Florida panther in 1994. No seropositive lynxes have ever been found, nor has PRV been detected in dead Iberian lynxes to date.

Case presentation

We describe the first reported case of pseudorabies in an Iberian lynx (Lynx pardinus). Pseudorabies was diagnosed in a young wild Iberian lynx from Extremadura (SW Spain) by histopathological examination, immunohistochemistry, polymerase chain reaction (PCR) and sequence analysis. Gross lesions included alopecia of the ventral neck, bloody gastro-intestinal contents and congestion of the brain. Histopathological analysis showed a moderate nonsuppurative meningoencephalitis with diffuse areas of demyelination, necrotizing gastritis and enteritis of the small intestine. Pseudorabies virus (PRV) antigen was found in neuronal and non-neuronal cells of the brain, tonsils, and gastric glandular epithelial cells by immunohistochemical analysis. The presence of the virus in the brain was confirmed by nested PCR. The sequence analysis of the 146 bp fragment (from the viral glycoprotein B gene) showed that the amplified sequence matched (with 100% identity) the PRV genome. Furthermore, specific DNA from glycoprotein D and E encoding-genes was detected by conventional and real-time PCR, respectively, confirming the latter that this infection was produced by a wild-type PRV strain.

Conclusions

This study supports the suspicion that PRV could infect the Iberian lynx. The detection of PRV in a dead Iberian lynx suggests that the virus may have a negative impact on the survival of endangered lynxes in the wild. However, because this is the first verified instance of lynx mortality resulting from pseudorabies, its true impact on the population is unknown.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0938-7) contains supplementary material, which is available to authorized users.

Epidemiological survey of enteric viruses in wild boars in the Czech Republic: First evidence of close relationship between wild boar and human rotavirus A strains

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Prevalence of enteric RNA-viruses in free-living wild boars was studied.

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Most frequent were teschovirus A, sapelovirus A, RVC; less prevalent RVA and EV-G.

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No PRRSV or members of family Coronaviridae were detected.

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We found close relationship between wild boar and domestic pig or human RVA strains.

Population of wild boar is increasing in the whole Europe, the animals migrate close to human habitats which greatly increases the possibility of natural transmission between domestic animals or humans and wild boars. The aim of the study was to estimate in population of free-living wild boar in the Czech Republic the prevalence of enteric viral pathogens, namely rotavirus groups A and C (RVA and RVC), porcine reproductive and respiratory syndrome virus (PRRSV), and members of family Coronaviridae (transmissible gastroenteritis virus – TGEV, porcine epidemic diarrhea virus − PEDV, porcine respiratory coronavirus – PRCV, and porcine hemagglutination encephalomyelitis virus – PHEV) and Picornaviridae,(teschovirus A – PTV, sapelovirus A – PSV, and enterovirus G – EV-G). In our study, stool samples from 203 wild boars culled during hunting season 2014–2015 (from October to January) were examined by RT-PCR. RVA was detected in 2.5% of tested samples. Nucleotide analysis of VP7, VP4, and VP6 genes revealed that four RVA strains belong to G4P[25]I1, G4P[6]I5, G11P[13]I5, and G5P[13]I5 genotypes and phylogenetic analysis suggested close relation to porcine and human RVAs. The prevalence of RVC in wild boar population reached 12.8%, PTV was detected in 20.2%, PSV in 8.9%, and EV-G in 2.5% of samples. During our study no PRRSV or coronaviruses were detected. Our study provides the first evidence of RVC prevalence in wild boars and indicates that wild boars might contribute to the genetic variability of RVA and also serve as an important reservoir of other enteric viruses.