Search

Despite the large wild boar population in South Korea, research on infectious diseases is limited. We investigated the prevalence of infectious diseases caused by Porcine Circovirus Type 2 (PCV2), Aujeszky's Disease Virus (ADV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Mycoplasma hyopneumoniae in 400 wild boars in South Korea. PCV2 antibodies were detected in 223 samples, antigens in 112, and both in 101. ADV and PRRSV antibodies were detected in one and three samples, respectively. M. hyopneumoniae antibodies were identified in 28 samples. PCV2 was detected in all nine regions, M. hyopneumoniae in five, PRRSV in three, and ADV in one. Infectious-disease monitoring is crucial to safeguard wild boars.

Background: Pseudorabies virus (PRV), porcine parvovirus (PPV) and porcine circovirus 3 (PCV3) are common in swine farms in China. Single infection or co-infection with PRV, PPV and/or PCV3 was difficult to distinguish between their clinical symptoms and pathological changes. Therefore, a quick and accurate detection method is needed for epidemiological surveillance, disease management, import and export control., Methods: In the present study, we established a multiplex real-time PCR assay based on SYBR Green I for the simultaneous detection of PRV, PPV and PCV3 genomes., Results: PRV, PPV and PCV3 were distinguished in the same sample by their different melting temperatures (Tm), with melting peaks at 90 °C for PRV, 84 °C for PPV and 80 °C for PCV3, respectively, and other non-targeted swine pathogens did not exhibit specific melting peaks. The assay showed a high degree of linearity (R 2 ≧0.995), and the detection limits were 4.76 copies/μL for PRV, 3.67 copies/μL for PPV, 3.07 copies/μL for PCV3 and 1.87 × 10 2 copies/μL for the three mixed plasmids, respectively. In this research, 81 clinical samples from pig farms in nine different regions of Guangdong Province were used to evaluate this new method. The detection rate of the multiplex real-time PCR assay was higher than that of the conventional PCR assay., Conclusions: This multiplex real-time PCR assay could be used as a diagnostic tool that is rapid, sensitive and reliable for the detection of co-infection of PRV, PPV and PCV3 as well as for molecular epidemiological surveillance., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Research Ethic Committee of the College of Life Science and Engineering, Foshan University. Experimental protocols for acquiring swine clinical samples were performed in strict accordance with the Chinese Regulations of Laboratory Animals. All of the farm owners provided written informed consent to collect the samples which were used in the study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Pseudorabies (PR) is a highly infectious disease caused by pseudorabies virus (PRV). This study aimed to detect and identify recent outbreaks of genotype Ⅱ PRV, and further analysis it's etiological characteristics and pathogenicity. The brain tissues with suspected PRV infection were isolated and the main virulence-related genes of the isolated PRV strain were amplified and sequenced for phylogenetic analysis. In addition, the pathogenicity of the isolated PRV strain to 6-week-old mice and 9-days-old suckling piglets were evaluated. The results showed that a PRV strain was successfully isolated and named PRV TJbd2023 strain, which could proliferate in PK-15 cells and TCID 50 of the 6th generation virus reached 10 7.57 /0.1 ml. Phylogenetic trees and amino acids analysis were constructed based on full-length gE sequences, which showed that PRV TJbd2023 strain was clustered into genetype Ⅱ PRV variant with a characteristic 21-nucleotide insertion (encoding 63 AASTPAA 69 ) in gC gene, and some amino acid point mutations were also found in other virulence-related genes, including gB protein R 223 H and E 836 K, gD protein R 320 S, and gE protein T 242 A. Animal experiments showed that TJbd2023 could cause acute neurological symptoms with 10 3.41 /mL LD 50 on KM mice, and intranasal inoculation of suckling piglets with 2 ml of TJbd2023 strain(10 6.57 /0.1 ml) led to a mortality rate of 66.70 %. Emerging genotype Ⅱ PRV variant such as isolated in our research named TJbd2023 with high pathogenicity might be responsible for recent outbreaks of PRV and immunization failure of Bartha-K61 vaccine in Tianjin, China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Pseudorabies is an infection of domestic and wild pigs that has occasionally been reported in dogs with fatal encephalitis. Hunting dogs are predisposed to pseudorabies exposure due to incorrect practices (administration of raw infected meat) or close contact with infected wild boars. This study described an outbreak of pseudorabies in two hunting dogs in the Campania region, southern Italy., Case Presentation: Two hunting dogs were hospitalized after a hunting trip, with fever, itching, and self-inflicted lesions. Laboratory tests showed mild anemia and marked leukocytosis. Despite conservative therapy, both animals died 48 h after the presentation of symptoms. One of the carcasses was sent to the Department of Veterinary Medicine and Animal Production in Naples to confirm the suspicion of pseudorabies. DNA was extracted from different matrices and used as a template for real-time PCR to detect PRV. Several samples (brain, cerebellum, brainstem, lung, and liver) tested positive. Subsequent sequence analyses of glycoprotein E from DNA extracted from the brain stem revealed a sequence similarity to those described in previous cases of pseudorabies in dogs in Italy, France and Belgium. One month after the outbreak, blood samples were collected from 42 dogs belonging to the same hunting team and from 245 dogs (cohort population) living in the Campania region. All samples were tested with two commercial ELISAs to detect seroconversion against glycoproteins B and E. A seroprevalence of 19% was observed in the hunting team affected by the outbreak, while only 0.8% was observed in the regional dog population., Conclusions: The data reported in this study demonstrate potential exposure to PRV by dead-end hosts, particularly hunting dogs. The sequencing results indicated the homogeneity of PRV strains circulating in the different Italian regions., (© 2024. The Author(s).)

Background: Pigs are susceptible to several ruminant pathogens, including Coxiella burnetti, Schmallenberg virus (SBV) and bovine viral diarrhea virus (BVDV). These pathogens have already been described in the pig population, although the dynamics of the infection and the impact on pig farms are currently unclear. The aim of this work was to evaluate the presence of these infections in the pig population of the Campania region, southern Italy, and to evaluate the risk factors associated with a greater risk of exposure., Results: A total of 414 serum samples belonging to 32 herds were tested for the presence of antibodies against SBV, Coxiella, and BVD using commercial multispecies ELISA kits. SBV (5.3%) was the most prevalent pathogen, followed by Coxiella (4.1%) and BVD (3%). The risk factors included in the study (age, sex, province, farming system, ruminant density and major ruminant species) had no influence on the probability of being exposed to BVD and Coxiella, except for the location, in fact more pigs seropositive to Coxiella were found in the province of Caserta. However, the univariate analysis highlighted the influence of age, location, and sex on exposure to SBV. The subsequent multivariate analysis statistically confirmed the importance of these factors. The presence of neutralizing antibodies for SBV and BVDV, or antibodies directed towards a specific phase of infection for Coxiella was further confirmed with virus-neutralization assays and phase-specific ELISAs in a large proportion of positive samples. The presence of high neutralizing antibody titers (especially for SBV) could indicate recent exposures. Twelve of the 17 positive samples tested positive for antibodies against Coxiella phase I or II antigens, indicating the presence of both acute and chronic infections (one animal tested positive for both phases antibodies)., Conclusions: Our study indicates a non-negligible exposure of pigs from southern Italy to the above pathogens. Further studies are necessary to fully understand the dynamics of these infections in pigs, the impact on productivity, and the public health consequences in the case of Coxiella., (© 2024. The Author(s).)

Background: The only natural hosts of Pseudorabies virus (PRV) are members of the family Suidae (Sus scrofa scrofa). In mammals, the infection is usually fatal and typically causes serious neurologic disease. This study describes four Aujeszky's disease cases in free-ranging Italian wolves (Canis lupus italicus). In Italy, the wolf is a strictly protected species and is in demographic expansion., Case Presentation: Three wolves (Wolf A, B, and C) were found in a regional park in Northern Italy, and one (Wolf D) was found in Central Italy. Wolf A and D were alive at the time of the finding and exhibited a fatal infection with epileptic seizures and dyspnoea, dying after a few hours. Wolf B presented scratching lesions under the chin and a detachment of the right earlobe, whilst Wolf C was partially eaten. The wolves showed hepatic congestion, diffuse enteritis, moderate pericardial effusion, severe bilateral pneumonia, and diffuse hyperaemia in the brain. The diagnostic examinations included virological analyses and detection of toxic molecules able to cause serious neurological signs. All four wolves tested positive for pseudorabies virus (PrV). The analysed sequences were placed in Italian clade 1, which is divided into two subclades, "a" and "b". The sequences of Wolf A, B, and C were closely related to other Italian sequences in the subclade b, originally obtained from wild boars and hunting dogs. The sequence from Wolf D was located within the same clade and was closely related to the French hunting dog sequences belonging to group 4., Conclusion: Results showed the presence of PrV strains currently circulating in wild boars and free-ranging Italian wolves. The genetic characterisation of the PrV UL44 sequences from the four wolves confirmed the close relationship with the sequences from wild boars and hunting dogs. This fact supports a possible epidemiological link with the high PrV presence in wild boars and the possibility of infection in wolves through consumption of infected wild boar carcasses or indirect transmission. To the best of our knowledge, this study is the first detection of Pseudorabies virus in free-ranging Italian wolves in northern and central Italy., (© 2023. The Author(s).)

Pseudorabies virus (PRV) is an important pathogen that can cause harm to the pig population. Since 2011, there have been a number of large-scale outbreaks of pseudorabies on Chinese farms where animals had been vaccinated with the Bartha-K61 vaccine. In order to understand the epidemiological trend and genetic variations of PRV in Guangxi province, China, 819 tissue samples were collected from swine farms where PRV infection was suspected from 2013 to 2019, and these were tested for infectious wild strains of PRV. The results showed a positive rate of PRV in Guangxi province of 28.21% (231/819). Thirty-six wild-type PRV strains were successfully isolated from PRV-positive tissue samples, and a genetic evolutionary analysis was performed based on the gB, gC, gD, gE, and TK genes. Thirty of the PRV strains were found to be closely related to the Chinese variant strains HeN1-China-2012 and HLJ8-China-2013. In addition, five PRV strains were genetically related to Chinese classical strains, and one isolate was a recombinant of the PRV variant and the vaccine strain Bartha-K61. Amino acid sequence analysis showed that all 36 PRV strains had characteristic variant sites in the amino acid sequences of the gB, gC, gD, and gE proteins. Pathogenicity analysis showed that, compared to classical PRV strains, the PRV variant strains were more pathogenic in mice and had a lower LD 50. Taken together, our results show that wild-type PRV infections are common on pig farms in Guangxi province of China and that the dominant prevalent strains were those of the PRV variants. The PRV variant strains also had increased pathogenicity in mice. Our data will provide a useful reference for understanding the prevalence and genetic evolution of PRV in China., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Pseudorabies virus (PRV) is a double-stranded linear DNA virus capable of infecting various animals, including humans. We collected blood samples from 14 provinces in China between December 2017 and May 2021 to estimate PRV seroprevalence. The PRV gE antibody was detected using the enzyme-linked immunosorbent assay (ELISA). Logistic regression analysis identified potential risk factors associated with PRV gE serological status at the farm level. Spatial-temporal clusters of high PRV gE seroprevalence were explored using SaTScan 9.6 software. Time-series data of PRV gE seroprevalence were modeled using the autoregressive moving average (ARMA) method. A Monte Carlo sampling simulation based on the established model was performed to analyze epidemic trends of PRV gE seroprevalence using @RISK software (version 7.0). A total of 40,024 samples were collected from 545 pig farms across China. The PRV gE antibody positivity rates were 25.04% (95% confidence interval [CI], 24.61% to 25.46%) at the animal level and 55.96% (95% CI, 51.68% to 60.18%) at the pig farm level. Variables such as farm geographical division, farm topography, African swine fever (ASF) outbreak, and porcine reproductive and respiratory syndrome virus (PRRSV) control in pig farms were identified as risk factors for farm-level PRV infection. Five significant high-PRV gE seroprevalence clusters were detected in China for the first time, with a time range of 1 December 2017 to 31 July 2019. The monthly average change value of PRV gE seroprevalence was -0.826%. The probability of a monthly PRV gE seroprevalence decrease was 0.868, while an increase was 0.132. IMPORTANCE PRV is a critical pathogen threatening the global swine industry. Our research fills knowledge gaps regarding PRV prevalence, infection risk factors, spatial-temporal clustering of high PRV gE seroprevalence, and the epidemic trend of PRV gE seroprevalence in China in recent years. These findings are valuable for the clinical prevention and control of PRV infection and suggest that PRV infection is likely to be successfully controlled in China., Competing Interests: The authors declare no conflict of interest.

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., (© 2023. The Author(s).)

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., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Pseudorabies virus (PRV), the causative agent of Aujeszky's disease, has gained increased attention in China in recent years due to outbreaks of emergent pseudorabies. However, there is limited information about the evolution and pathogenicity of emergent PRV field strains in China. In this study, two PRV field strains were isolated from an intensive pig farm with suspected PRV infection. These were named the GXLB-2015 and GXGG-2016 strains and their growth characteristics together with their genome sequences and pathogenicity were determined. Nucleotide homology and phylogenetic analysis revealed the GXLB-2015 stain was relatively close to the foreign PRV isolated strains with respect to the whole genome sequence. However, it formed an independent branch between the foreign PRV isolates and the previous PRV variants isolated in China. Further recombination and genetic evolution analysis showed that the GXLB-2015 strain was a natural recombinant between the Bartha strain and PRV variants. The GXGG-2016 strain was highly homologous with the Chinese classical strains, but it has a natural deletion of 69 aa in the thymidine kinase (TK) gene. Pathogenicity analysis showed that, the GXLB-2015 strain had the strongest pathogenicity to mice with an LD 50 of 10 3.5 , while the GXGG-2016 strain with the TK gene deletion was not pathogenic to mice. Taken together, our data provide direct evidence for the genomic recombination and natural TK gene deletion of PRVs, which may provide a reference for a better understanding of PRV evolution in China and contribute to the clinical control of PRV infection in pig farms., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Aujeszky's disease is mainly a swine disease, still endemic worldwide. It can infect other mammalians, including human beings, and it is usually fatal with nervous symptoms. Ever since the disease was detected in 1988 in Argentina, many outbreaks have been reported involving both feral swine and dogs., Aim: At present, in Argentina, Pseudorabies virus (PRV) cases are sporadically reported; however, clinical cases are informed. This study aims to obtain information about the seroprevalence of PRV in wild boars and to isolate and characterize PRV from clinical samples., Methods: From 2018 to 2019, 78 wild boars' serum samples from Bahía de Samborombón natural reserve were analyzed for antibodies to PRV using a virus neutralization test. Clinical samples from 17 pigs, 2 wild boars, 1 dog, and 1 cat were collected from 2013 to 2019 for viral isolation and detection of the presence of the gD gene by PCR. For sequence analysis, the gC partial gene was amplified., Results: Five strains were isolated from the dog, cat, and swine samples. The new PRV strains identified were confirmed by BLAST analysis, which revealed between 99.74% and 100% of similarity to the NIA-3 strain and phylogenetic analysis of the partial gene encoding the gC protein revealed that the PRV strains have divided into two main clades, clade 1 and clade 2., Conclusion: This report informed that most new cases of PRV were detected in the central regions of Argentina, where pig production is concentrated. The study in Bahía de Samborombón revealed a high percentage of detection but, the sampling is not representative of that of the rest of the country. Therefore, a systematic sampling effort of wild boar throughout the country should be included in the national program control. Although in Argentina only the inactivated Bartha vaccine is allowed, recombination risk should not be ignored if attenuated vaccines are incorporated into the National control plan. The two strains, one from the cat and one from the dog sample, are directly related to infected swine. The information about clinical cases and molecular characterization of new strains is important for a better understanding of the dynamics of PRV and to promote preventive measures., Competing Interests: The authors declare that there is no competing interest regarding the publication of this paper.

Pseudorabies virus (PRV) has received widespread attention for its potential health effects on humans, wildlife, domestic animals, and livestock. In this review, we focus on PRV dynamics in wildlife, given the importance of wild-origin PRV transmission to domestic and farm animals. Wild boars, pigs, and raccoons can serve as reservoirs of PRV, with viral transmission to domestic livestock occurring via several routes, such as wild herd exposure, contaminated meat consumption, and insect vector transmission. Many endangered feline and canine species can be infected with PRV, with acute disease and death within 48 h. The first confirmed human case of PRV infection in mainland China was reported in 2017. Thus, PRV exhibits potentially dangerous cross-host transmission, which is likely associated with inappropriate vaccination, poor awareness, and insufficient biosecurity. Currently, no vaccine provides full protection against PRV in all animals. Here, we summarize the epidemiology and pathogenesis of PRV infection in wild, domestic, and farmed animals, which may facilitate the design of novel therapeutics and strategies for controlling PRV infection and improving wildlife protection in China.

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.

We sequenced the complete genome of the pseudorabies virus (PRV) FJ epidemic strain, and we studied the characteristics and the differences compared with the classical Chinese strain and that of other countries. Third-generation sequencing and second-generation sequencing technology were used to construct, sequence, and annotate an efficient, accurate PRV library. The complete FJ genome was 143,703 bp, the G+C content was 73.67%, and it encoded a total of 70 genes. The genetic evolution of the complete genome and some key gene sequences of the FJ strain and PRV reference strains were analyzed by the maximum likelihood (ML) method of MEGA 7.0 software. According to the ML tree based on the full-length genome sequences, PRV FJ strain was assigned to the branch of genotype II, and it showed a close evolutionary relationship with PRV epidemic variants isolated in China after 2011. The gB, gC, gD, gH, gL, gM, gN, TK, gI, and PK genes of the FJ strain were assigned to the same branch with other Chinese epidemic mutants; its gG gene was assigned to the same branch with the classic Chinese Fa and Ea strains; and its gE gene was assigned to a relatively independent branch. Potential recombination events were predicted by the RDP4 software, which showed that the predicted recombination sites were between 1694 and 1936 bp, 101,113 and 102,660 bp, and 107,964 and 111,481 bp in the non-coding region. This result broke the previously reported general rule that pseudorabies virus recombination events occur in the gene coding region. The major backbone strain of the recombination event was HLJ8 and the minor backbone strain was Ea. Our results allowed us to track and to grasp the recent molecular epidemiological changes of PRV. They also provide background materials for the development of new PRV vaccines, and they lay a foundation for further study of PRV.

In recent years, the prevalence of pseudorabies virus (PRV) has caused huge economic losses to the Chinese pig industry. Meanwhile, PRV infection in humans also sounded the alarm about its cross-species transmission from pigs to humans. To study the regional PRV epidemic, serological and epidemiological investigations of PRV in pig populations from Yunnan Province during 2017-2021 were performed. The results showed that 31.37% (6324/20,158, 95% CI 30.73-32.01) of serum samples were positive for PRV glycoprotein E (gE)-specific antibodies via enzyme-linked immunosorbent assay (ELISA). The risk factors, including the breeding scale and development stage, were significantly associated with PRV seroprevalence among pigs in Yunnan Province. Of the 416 tissue samples collected from PRV-suspected pigs in Yunnan Province, 43 (10.33%, 95% CI 7.41-13.26) samples were positive for PRV- gE nucleic acid in which 15 novel PRV strains from these PRV-positive samples were isolated, whose gC and gE sequences were analyzed. Phylogenetic analysis showed that all 15 isolates obtained in this study belonged to the genotype II. Additionally, the gC gene of one isolate (YuN-YL-2017) was genetically closer to variant PRV strains compared with others, while the gE gene was in the same clade with other classical PRV strains, indicating that this isolate might be a recombinant strain generated from the classical and variant strains. The results revealed the severe PRV epidemic in Yunnan Province and indicated that PRV variants are the major genotypes threatening the pig industry development.

Feral swine (Sus scrofa), an important prey species for the endangered Florida panther (Puma concolor coryi), is the natural host for pseudorabies virus (PRV). Prior to this study, PRV had been detected in just three panthers. To determine the effect of PRV on the panther population, we prospectively necropsied 199 panthers and retrospectively reviewed necropsy and laboratory findings, reexamined histology, and tested archived tissues using real-time PCR from 46 undiagnosed panther mortalities. Seven additional infections (two prospective, five retrospective) were detected for a total of 10 confirmed panther mortalities due to PRV. To further evaluate the effect of PRV, we categorized radio-collared (n=168) and uncollared panther mortalities (n=367) sampled from 1981 to 2018 based on the likelihood of PRV infection as confirmed, probable, suspected, possible, or unlikely/negative. Of 168 radio-collared panthers necropsied, PRV was the cause of death for between eight (confirmed; 4.8%) and 32 (combined confirmed, probable, suspected, and possible categories; 19.0%) panthers. The number of radio-collared panther mortalities due to PRV was estimated to be 15 (95% empirical limits: 12-19), representing 8.9% (confidence interval: 4.6-13.2%) of mortalities. Gross necropsy findings in 10 confirmed cases were nonspecific. Microscopic changes included slight to mild perivascular cuffing and gliosis (primarily in the brain stem), lymphoplasmacytic meningoencephalitis (cerebral cortex), and intranuclear inclusion bodies (adrenal medulla). The PRV glycoprotein C gene sequences from three positive panthers grouped with the sequence from a Florida feral swine. Our findings indicate that PRV may be an important and underdiagnosed cause of death in Florida panthers., (© Wildlife Disease Association 2021.)

Little is known about disease transmission relevant contact rates at the wildlife-livestock interface and the factors shaping them. Indirect contact via shared resources is thought to be important but remains unquantified in most systems, making it challenging to evaluate the impact of livestock management practices on contact networks. Free-ranging wild pigs (Sus scrofa) in North America are an invasive, socially-structured species with an expanding distribution that pose a threat to livestock health given their potential to transmit numerous livestock diseases, such as pseudorabies, brucellosis, trichinellosis, and echinococcosis, among many others. Our objective in this study was to quantify the spatial variations in direct and indirect contact rates among wild pigs and cattle on a commercial cow-calf operation in Florida, USA. Using GPS data from 20 wild pigs and 11 cattle and a continuous-time movement model, we extracted three types of spatial contacts between wild pigs and cattle, including direct contact, indirect contact in the pastoral environment (unknown naturally occurring resources), and indirect contact via anthropogenic cattle resources (feed supplements and water supply troughs). We examined the effects of sex, spatial proximity, and cattle supplement availability on contact rates at the species level and characterized wild pig usage of cattle supplements. Our results suggested daily pig-cattle direct contacts occurred only occasionally, while a significant number of pig-cattle indirect contacts occurred via natural resources distributed heterogeneously across the landscape. At cattle supplements, more indirect contacts occurred at liquid molasses than water troughs or molasses-mineral block tubs due to higher visitation rates by wild pigs. Our results can be directly used for parameterizing epidemiological models to inform risk assessment and optimal control strategies for controlling transmission of shared diseases., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Pseudorabies (PR), also called Aujeszky's disease, is a highly infectious disease caused by pseudorabies virus (PRV). Without specific host tropism, PRV can infect a wide variety of mammals, including pig, sheep, cattle, etc., thereby causing severe clinical symptoms and acute death. PRV was firstly reported in China in 1950s, while outbreaks of emerging PRV variants have been documented in partial regions since 2011, leading to significant economic losses in swine industry. Although scientists have been devoting to the design of diagnostic approaches and the development of vaccines during the past years, PR remains a vital infectious disease widely prevalent in Chinese pig industry. Especially, its potential threat to human health has also attracted the worldwide attention. In this review, we will provide a summary of current understanding of PRV in China, mainly focusing on PRV history, the existing diagnosis methods, PRV prevalence in pig population and other susceptible mammals, molecular characteristics, and the available vaccines against its infection. Additionally, promising agents including traditional Chinese herbal medicines and novel inhibitors that may be employed to treat this viral infection, are also discussed., (© 2021. Wuhan Institute of Virology, CAS.)

In late 2011, the outbreak of pseudorabies (PR) occurred in Bartha-K61-vaccinated pig farms and spread rapidly to many provinces of China, causing substantial economic losses to the swine industry. A total of 4708 pig serum samples from Henan province during 2018-2019 were collected to screen for the presence of pseudorabies virus (PRV) gE-specific antibodies, and phylogenetic analysis based on the gE gene of PRV was performed. Of the 4708 serum samples tested, 30.14% (1419/4708) were seropositive for PRV antibodies, based on PRV gE-coated enzyme-linked immunosorbent assay (ELISA), with slaughterhouses having the highest seroprevalence. The seropositive rates of PRV also varied with the region and the season. Phylogenetic analysis showed that three PRV isolates from this study were clustered in an independent branch together with the Chinese variant PRV strains (after 2012), and had a closer genetic relationship with the Chinese variant PRV strains, but differed genetically from the 4 early Chinese PRV strains and 4 European-American strains. This study suggests that three PRV isolates may belong to PRV variants, and the development of a novel vaccine against PRV variants is particularly urgent., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Pseudorabies virus (PRV) is an economically significant swine infectious agent. A PRV outbreak took place in China in 2011 with novel virulent variants. Although the association of viral genomic variability with pathogenicity is not fully confirmed, the knowledge concerning PRV genomic diversity and evolution is still limited. Here, we sequenced 54 genomes of novel PRV variants isolated in China from 2012 to 2017. Phylogenetic analysis revealed that China strains and US/Europe strains were classified into two separate genotypes. PRV strains isolated from 2012 to 2017 in China are highly related to each other and genetically close to classic China strains such as Ea, Fa, and SC. RDP analysis revealed 23 recombination events within novel PRV variants, indicating that recombination contributes significantly to the viral evolution. The selection pressure analysis indicated that most ORFs were under evolutionary constraint, and 19 amino acid residue sites in 15 ORFs were identified under positive selection. Additionally, 37 unique mutations were identified in 19 ORFs, which distinguish the novel variants from classic strains. Overall, our study suggested that novel PRV variants might evolve from classical PRV strains through point mutation and recombination mechanisms.

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., (© Wildlife Disease Association 2021.)

We isolated two pseudorabies virus (PRV) isolates (designated OT-1 and OT-2) from two hunting dogs exhibiting neurological manifestations after eating the flesh of wild boar hunted in Oita prefecture, Kyushu Island, Japan. The isolates corresponded to a previously reported PRV (MY-1 strain) isolated from a hunting dog in neighboring Miyazaki prefecture, and it clustered into genotype II based on the glycoprotein C sequence. Our results suggest that this common PRV strain may have been maintained in wild boars on Kyushu Island even though domestic pigs in this area have attained an Aujeszky's disease-free status.

Background: Porcine circovirus type 2 (PCV2) is one of the crucial swine viral pathogens, caused porcine circovirus associated diseases (PCVAD). Shandong province is one of the most important pork producing areas and bears a considerable economic loss due to PCVAD. However, there is limited information on epidemiology and coinfection rate of PCV2 with other critical swine diseases in this area, such as porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), Pseudorabies virus (PRV), and porcine epidemic diarrhea virus (PEDV)., Results: Overall, 89.59% serum samples and 36.98% tissue samples were positive for PCV2 specified ELISA and PCR positive for PCV2, respectively. The coinfection rates of PCV2 with PRRSV, PRV, CSFV, and PEDV were 26.73%, 18.37%, 13.06%, and 3.47%, respectively. Moreover, genetic characteristic of PCV2 were analyzed based on the cap genes showing that PCV2d is the dominant sub-genotype circulating in the province., Conclusions: Our findings reveal that PCV2d, as the dominant strain, is prevailing in pig farms in Shandong province at high levels. There was a high frequency of coinfection of PCV2 and PRRSV.

Porcine respiratory disease complex (PRDC), a respiratory disease caused by a variety of factors, is one of the most common problems in the intensive pig farms. To investigate the mixed infection incidence of wild-type pseudorabies virus (WT PRV) and respiratory bacteria, a total of 1,293 clinical samples were collected from pigs with typical respiratory signs from 14 different provinces of China from September 2016 to February 2018. The WT PRV was detected by ELISA targeting gE antibody while the bacteria were detected by bacterial isolation and serotyping by PCR. The results revealed that the detection rate of A. pleuropneumoniae and B. bronchiseptica infection associated with WT PRV infection were 6.30% and 15.99%, respectively, which were significantly higher than those without WT PRV infection (3.41% and 4.41%) at the farm level (p < .05). There were no significant differences in the detection rate of H. parasuis, S. suis or P. multocida between WT PRV positive and negative farms (p > .05). However, the detection rate of attenuated H. parasuis and S. suis strains were 68.19% and 64.75%, respectively, in WT PRV infected farms, which were significantly higher than those (41.56% and 52.25%) in WT PRV free farms (p < .05). The prevalent serotypes of H. parasuis-5/12 and S. suis-2 were also investigated by multiplex PCR. These results indicated that the presence of WT PRV increased the chance of bacterial infection and the number of pathogenic strains in the respiratory system of pigs. Therefore, the eradication of pseudorabies is an effective approach to prevent and control the bacterial respiratory diseases in the intensive pig farms in China., (© 2020 The Authors. Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Background: The relevance of the study is determined by the danger that this disease poses to all types of domestic animals in the Republic of Kazakhstan, as well as the significant damage caused by this situation to the entire agriculture of the Republic of Kazakhstan. Timely and competent analysis of the epizootic situation for this disease in the country will reliably determine the development tendencies of this condition and predetermine a set of measures that should be taken to combat this animal disease in agricultural regions of the Republic of Kazakhstan., Aim: This study examines the development of the epizootic situation of Aujeszky's disease within the territory of the Republic of Kazakhstan., Methods: To achieve the set research goal, a combination of quantitative and qualitative research methods are used., Results: The results of this research article can be of significant importance for livestock breeders in the Republic of Kazakhstan, who are working on raising the number of pigs and other types of domestic animals and are interested in a further increase in the number., Conclusion: From a practical standpoint, the significance of this study is conditioned by the possibility of searching and determining the main directions of the spread of the disease under consideration in agricultural lands and regions of the Republic of Kazakhstan, as well as taking a set of measures to eradicate such a disease and prevent its future occurrence in the country.

The control and elimination of pseudorabies (PR) is one of the most important goals in the pig industry. After the first PR outbreak in Korea in 1986, all pigs infected with PR virus (PRV) were removed, and a vaccination program for pigs was implemented. No PR has occurred in Korea since 2010, and vaccination was discontinued after 2013. Information on the seroprevalence of PRV in pigs, including wild boars ( Sus scrofa ), is important for evaluating the PR status in a country. In this study, 2.65% (28/1057) of the wild boars tested had antibodies against PRV in 2018, indicating that PRV has been circulating continuously in the wild boar population in Korea. Effective means should be implemented to prevent the transmission of PRV between wild and domestic pigs, because the wild boar is a potential reservoir host for PRV.

We investigated the landscape epidemiology of a globally distributed mammal, the wild pig (Sus scrofa), in Florida (U.S.), where it is considered an invasive species and reservoir to pathogens that impact the health of people, domestic animals, and wildlife. Specifically, we tested the hypothesis that two commonly cited factors in disease transmission, connectivity among populations and abundant resources, would increase the likelihood of exposure to both pseudorabies virus (PrV) and Brucella spp. (bacterial agent of brucellosis) in wild pigs across the Kissimmee Valley of Florida. Using DNA from 348 wild pigs and sera from 320 individuals at 24 sites, we employed population genetic techniques to infer individual dispersal, and an Akaike information criterion framework to compare candidate logistic regression models that incorporated both dispersal and land cover composition. Our findings suggested that recent dispersal conferred higher odds of exposure to PrV, but not Brucella spp., among wild pigs throughout the Kissimmee Valley region. Odds of exposure also increased in association with agriculture and open canopy pine, prairie, and scrub habitats, likely because of highly localized resources within those land cover types. Because the effect of open canopy on PrV exposure reversed when agricultural cover was available, we suggest that small-scale resource distribution may be more important than overall resource abundance. Our results underscore the importance of studying and managing disease dynamics through multiple processes and spatial scales, particularly for non-native pathogens that threaten wildlife conservation, economy, and public health.

Pseudorabies (PR) is a highly contagious disease affecting a wide range of animals, which annually causes great economic losses in China. In this study, a total number of 18,815 serum samples and 1,589 tissue samples were collected from 311 intensive pig farms (≥350 sows) located in eight cities in Heilongjiang province, and tested by ELISA and PCR. Overall, the serum positive rates of gE and gB protein were 16.3% and 84.5%, respectively. The PCR-positive rate of PR virus (PRV) in tissue samples was 17.8%. The coinfection rates of PRV with porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), and classical swine fever virus (CSFV) were also measured. The rate of PRV coinfected with PRRSV was 36.0% followed by 12.9% with PCV2 and 1.8% with CSFV, respectively. These results clearly demonstrate PRV prevalence and its coinfection rate in Heilongjiang province, indicating high PR endemic in pig farms in this region. This study provides data for further epidemiological investigations and a reference for developing PRV control strategies in this region and in China.

Free-ranging wild boars (Sus scrofa) from two different Brazilian biomes were sampled. Only one of 36 (2.8%) animals tested from central-western Brazil were positive for antibodies against pseudorabies virus (PRV) by enzyme-linked immunosorbent assay. Peccaries and other wildlife species can be exposed to PRV in these areas. In addition, wild boars could have impact on livestock and PRV eradication., (© Wildlife Disease Association 2020.)

In the present study, a specific and reliable duplex SYBR green I-based quantitative real-time polymerase chain reaction assay was established to detect pseudorabies virus (PRV) and porcine circovirus 3 (PCV3) simultaneously. Viral genomes of PRV and PCV3 in one specimen were identified by their different melting temperatures with melting peaks at 87 °C and 81 °C for PRV and PCV3 respectively, whilst other non-targeted swine pathogens exhibited no fluorescent signals. The assay displayed a high degree of linearity (R 2  > 0.997), and the limits of detection were 37.8 copies/μL, 30.6 copies/μL and 60 copies/μL for PRV, PCV3 and the mixture of two recombinant plasmids, respectively. It had good repeatability and reproducibility, and the coefficients of variation in intra-batch and inter-batch assays were all less than 2.0%. In this research, the duplex assay was further evaluated using 117 clinical tissue specimens from diseased pigs in the field. The results revealed the infection rates of PRV and PCV3 were 23.08% (27/117) and 55.56% (65/117) respectively, and PRV and PCV3 co-infection rate was 14.53% (17/117). The assay could be utilized as a diagnostic tool with specificity, sensitivity, and reliability for molecular epidemiological surveillance of PRV and PCV3., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Rationale/background: Though much smaller than the bovine industry, the porcine sector in Argentina involves a large number of farms and represents a significant economic sector. In recent years Argentina has implemented a national registry of swine movements amongst other measures, in an effort to control and eventually eradicate endemic Aujesky's disease. Such information can prove valuable in assessing the risk of transmission between farms for endemic diseases but also for other diseases at risk of emergence., Methods: Shipment data from 2011 to 2016 were analyzed in an effort to define strategic locations and times at which control and surveillance efforts should be focused to provide cost-effective interventions. Social network analysis (SNA) was used to characterize the network as a whole and at the individual farm and market level to help identify important nodes. Spatio-temporal trends of pig movements were also analyzed. Finally, in an attempt to classify farms and markets in different groups based on their SNA metrics, we used factor analysis for mixed data (FAMD) and hierarchical clustering., Results: The network involved approximate 136,000 shipments for a total of 6 million pigs. Over 350 markets and 17,800 production units participated in shipments with another 83,500 not participating. Temporal data of shipments and network metrics showed peaks in shipments in September and October. Most shipments where within provinces, with Buenos Aires, Cordoba and Santa Fe concentrating 61% of shipments. Network analysis showed that markets are involved in relatively few shipments but hold strategic positions with much higher betweenness compared to farms. Hierarchical clustering yielded four groups based on SNA metrics and node characteristics which can be broadly described as: 1. small and backyard farms; 2. industrial farms; 3. markets; and 4. a single outlying market with extreme centrality values., Conclusion: Characterizing the network structure and spatio-temporal characteristics of Argentine swine shipments provides valuable information that can guide targeted and more cost-effective surveillance and control programs. We located key nodes where efforts should be prioritized. Pig network characteristics and patterns can be used to create dynamic disease transmission models, which can both be used in assessing the impact of emerging diseases and guiding efforts to eradicate endemic ones., Competing Interests: The authors have declared that no competing interests exist.

Background: Pseudorabies, also known as Aujeszky's disease, is caused by the pseudorabies virus (PRV) and has been recognized as a critical disease affecting the pig industry and a wide range of animals around the world, resulting in great economic losses each year. Shandong province, one of the most vital food animal-breeding regions in China, has a very dense pig population, within which pseudorabies infections were detected in recent years. The data, however, on PRV epidemiology and coinfection rates of PRV with other major swine diseases is sparse., Objectives: This study aimed to investigate the PRV epidemiology in Shandong and analyze the current control measures., Methods: In this study, a total number of 16,457 serum samples and 1,638 tissue samples, which were collected from 362 intensive pig farms (≥ 300 sows/farm) covered all cities in Shandong, were tested by performing enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR)., Results: Overall, 52.7% and 91.5% of the serum samples were positive for PRV-gE and -gB, respectively, based on ELISA results. In addition, 15.7% of the tissue samples were PCR positive for PRV. The coinfection rates of PRV with porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus, and classical swine fever virus were measured; coinfection with PCV2 was 35.0%, higher than those of the other two viruses. Macroscopic and microscopic lesions were observed in various tissues during histopathological examination., Conclusions: The results demonstrate the PRV prevalence and its coinfection rates in Shandong province and indicate that pseudorabies is endemic in pig farms in this region. This study provides epidemiological data that can be useful in the prevention and control of pseudorabies in Shandong, China., Competing Interests: The authors have no conflicts of interest to declare., (© 2020 The Korean Society of Veterinary Science.)

Pseudorabies virus (PRV) infects numerous species of domestic and wild animals leading to severe diseases especially in swine and cattle. Since 2011, the variant PRVs were identified in pigs, which were genetically different from classic strains. Although variant PRV infection is widely observed in pigs, there is still no report of variant PRV infection in cattle. Here, we reported a natural infection of variant PRV leading to acute bovine death in Eastern China. Our study suggests that the new variant PRV strains could be a potential threat to cattle industry and possibly to the public health of human., (© 2019 Blackwell Verlag GmbH.)

Aujeszky's disease (AD) virus is enzootic in Iberian wild boar, thus posing a threat to the official eradication of AD on extensive domestic pig farms in Spain. Understanding the dynamics and drivers of ADV infection in wild boar will help prevent viral transmission at the wild boar-pig interface. This study analyses the dynamics of ADV infection in wild boar and tests relevant hypotheses in order to identify drivers of ADV infection dynamics. Wild boar sera (N = 971) and oropharyngeal tonsils (TN, N = 549) collected over 11 consecutive years in south-western Spain were tested for ADV antibodies and DNA, respectively. We tested the hypotheses that population immunity modulates the risk of ADV infection (H 1 ) and that detecting ADV DNA in TN is a good proxy of the annual ADV infection pressure (H 2 ). This was done by building logistic regression models that were subsequently employed to test the influence of a series of host population and host individual factors-including predictors of ADV immunity in the population-on the annual risk of new ADV infections and on the presence of ADV DNA in TN. The premise of H 1 was that there would be a negative association between the proportion of ADV antibody-positive wild boar in a given year and the risk of ADV infection of naïve individuals. There was, however, a positive association, and H 1 was, therefore, rejected. If detecting ADV in TN had been a good indicator of ADV infection pressure, a positive association with the proportion of ADV antibody-positive wild boar would have been found. However, this was not the case and H 2 was also rejected. We confirmed that ADV infection is a dynamic phenomenon. The risk of infection with ADV can change considerably between consecutive years, and these changes are positively associated with the proportion of infected wild boar in the population., (© 2019 Blackwell Verlag GmbH.)

Since late 2011, outbreaks of pseudorabies virus (PRV) have occurred in southern China causing major economic losses to the pig industry. We previously reported that variant PRV forms and recombination in China could be the source of continued epidemics. Here, we analyzed samples from intensive pig farms in eastern China between 2017 and 2019, and sequenced the main glycoproteins (gB, gC, gD, and gE) to study the evolution characteristics of PRV. Based on the gC gene, we found that PRV variants belong to clade 2 and detected a founder effect during by the PRV epidemic. In addition, we detected inter- and intra-clade recombination; in particular, inter-clade recombination in the gB genes of strains FJ-ZXF and FJ-W2, which were recombinant with clade 1 strains. We also found specific amino-acid changes and positively selected sites, possibly associated with functional changes. This analysis of the emergence of PRV in China illustrates the need for continuous monitoring and the development of vaccines against specific variants of PRV.

Direct contact with swine infected by Aujeszky's disease virus (ADV) represents a potential risk of transmission to carnivore species, in which the infection is normally fatal. We assessed exposure to ADV in hunting dogs in an area where the virus is highly endemic in wild boar populations. Two out of 466 (0.43%; 95% CI 0.00-1.02%) hunting dogs analyzed were positive by gE-bELISA, gB-bELISA and the virus neutralization test. The seroprevalence levels detected, as well as the absence of reports of clinical cases in the hunting dog groups tested, indicate limited contact of this species with ADV in the study area. Further studies are warranted to assess the pathogenicity of Aujeszky's disease virus strains infecting wild boar.

USDA APHIS Wildlife Services (WS) responded to the threat of feral swine as a pathogen reservoir as early as 2004. To increase awareness and knowledge on that risk, WS began opportunistic sampling of animals harvested by its operational component to curtail swine damage to agriculture and property. Initially, pseudorabies and swine brucellosis were of most concern, as both serve as a potential threat to the domestic swine industry and the latter also possesses zoonotic implications. In 2006, classical swine fever, a foreign animal disease, became the main driver for feral swine pathogen surveillance. Subsequent years of surveillance identified numerous other disease risks inherent within populations of feral swine. Presently, feral swine surveillance falls under the purview of the APHIS National Feral Swine Damage Management Program, which began in 2014. In January 2018, a panel of animal disease experts representing industry, government, and academia were invited to Fort Collins, Colorado to discuss successes of this surveillance, identify any shortcomings or needs, and propose future feral swine surveillance. This manuscript serves to synthesize WS' surveillance and the future direction of these efforts., (Published by Oxford University Press on behalf of the American Society of Animal Science 2019.)

Background: Pseudorabies virus (PRV) causes Aujeszky's disease in pigs and can be transmitted to other mammals, including humans. In the current study, we systematically studied the interspecies transmission and evolutionary history of PRV., Methods: We performed comprehensive analysis on the phylodynamics, selection, and structural biology to summarize the phylogenetic and adaptive evolution of PRV based on all available full-length and major glycoprotein sequences., Results: PRV can be divided into 2 main clades with frequent interclade and intraclade recombination. Clade 2.2 (variant PRV) is currently the most prevalent genotype worldwide, and most commonly involved in cross-species transmission events (including humans). We also found that the population size of clade 2.2 has increased since 2011, and the effective reproduction number was >1 from 2011 to 2016, indicating that PRV may be still circulating in swine herds and is still a risk in relation with cross-species transmission in China. Of note, we identified amino acid sites in some important glycoproteins gB, gC, gD, and gE that may be associated with PRV adaptation to new hosts and immune escape to vaccines., Conclusions: Our study provides important genetic insight into the interspecies transmission and evolution of PRV within and between different hosts that warrant additional surveillance., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

In this study, we reported a moderately pathogenic pseudorabies virus (PRV) variant isolated from one Bartha-K61-vaccinated pig farm in Weifang, Shandong Province, China, 2014. The sick piglets in the farm were characterized by anorexia, weight loss and neurologic symptoms but did not die. Sequence alignment of the gE gene indicated that it belonged to a new mutated PRV strain and about 15% amino acid sites had mutations, deficiencies and insertions compared to the other PRV strains. The gD gene had two amino acid insertions and ten amino acid mutations in comparison with the Bartha-K61 vaccine strain. The TK and gM genes were the same as one highly pathogenic PRV TJ strain. Evidence from virus isolation, laboratory challenge, serological detection and histopathologic examination confirmed that the etiological agent of the disease is PRV SD1404, which is a moderately pathogenic strain and causes piglets to be sick but not to die. PRV SD1404 strain is different from other reports and should be paid more attention to avoid economic losses., (Copyright © 2018. Published by Elsevier B.V.)

Hog pseudorabies (Aujeszky's disease) can incur serious losses for farm owners and even the entire hog industry by causing infertility, abortion, and stillbirth among sows, as well as diarrhoea, respiratory failure, and death among piglets. Pseudorabies virus could be prevented, controlled, and eliminated by clean-up at both farm and regional levels through a strict procedure of vaccination, quarantine, diagnosis, elimination of positive animals, and healthy animals nurturing. Using data from 63 large-scale hog farms from nine provinces (municipalities, autonomous regions) of China, we evaluated the economic consequences of hog pseudorabies clean-up in China's hog farms based on a partial budgeting method. By comparing large-scale hog farms that have performed pseudorabies clean-up with similar farms that have not, we analysed how clean-up affected farm profit and whether there existed sufficient economic incentives for farm owners to adopt pseudorabies control measures. Further, we examined how the economic consequences varied with factors such as clean-up history and farm size. The findings showed that, on average, clean-up adopters outperformed non-adopters by 8.02 million yuan per farm per year within the four years post clean-up adoption. Also, we found that the net profit changes attributable to pseudorabies clean-up increased over time and with farm size. Although we cannot extrapolate to all Chinese hog farms, these findings suggest that the earlier a hog farm adopted pseudorabies clean-up, the larger the economic benefits would be, especially for large-scale farms., (Copyright © 2018. Published by Elsevier B.V.)

Although  the  eradication  of  Pseudorabies  virus  (PrV)  in  domestic  pigs  is  ongoing,  the circulation  of  this  virus  in  wild  boars  remains  a  threat  in  the  currently  unprotected, 'low prevalence', pig population. In this study, we reported PrV prevalence data and the influence of  possible  risk  factors  in  2  North-West  Italian  wild  boar  populations  (free  and  enclosed) with the goal of supporting the implementation of a risk-based AD surveillance system. Sera from  1,425  wild  boars  were  collected  between  2011  and  2015  and  tested  by  ELISA  for  the presence  of  PrV  antibodies;  the  overall  raw  seroprevalence  was  30.39%  (433/1,425;  CI  95% 28.01-32.85%).  A  significant  difference  was  however  observed  between  the  prevalence rates  of  the  free  range  population  (9.98%;  90/902;  CI  95%;  8.10-12.12%)  and  the  enclosed  population of La Mandria park (Piedmont, Italy) (65.58%; 343/523; CI 95%; 61.51-69.65%). In both populations a significantly higher number of adults and females were found positive to PrV  ELISA.  Specific  territorial  data  on  PrV  circulation  in  wild  boars  should  be  acquired  from other regions for guiding risk-based measures in order to reduce the threat of AD re-infection in a more cost-effective manner.

Land use influences disease emergence by changing the ecological dynamics of humans, wildlife, domestic animals, and pathogens. This is a central tenet of One Health, and one that is gaining momentum in wildlife management decision-making in the United States. Using almost 2000 serological samples collected from non-native wild pigs ( Sus scrofa ) throughout Florida (U.S.), we compared the prevalence and exposure risk of two directly transmitted pathogens, pseudorabies virus (PrV) and Brucella spp., to test the hypothesis that disease emergence would be positively correlated with one of the most basic wildlife management operations: Hunting. The seroprevalence of PrV- Brucella spp. coinfection or PrV alone was higher for wild pigs in land management areas that allowed hunting with dogs than in areas that culled animals using other harvest methods. This pattern did not hold for Brucella alone. The likelihood of exposure to PrV, but not Brucella spp., was also significantly higher among wild pigs at hunted sites than at sites where animals were culled. By failing to consider the impact of dog hunting on the emergence of non-native pathogens, current animal management practices have the potential to affect public health, the commercial livestock industry, and wildlife conservation.

Background: Pigs (Sus scrofa) are the natural hosts of pseudorabies virus (PRV), also known as Aujeszky's disease. Infection in mammals, with the exception of humans, typically causes extreme itching, facial swelling, and excessive salivation, followed by death in non-suid species. The risk to susceptible mammals was assumed to decrease when PRV was eliminated from U.S. commercial swine in 2004, though the virus remains endemic in feral swine. Infected feral swine pose a threat to the disease-free status of the commercial swine industry, and to other animals, including dogs, that come in direct or indirect contact with them. Since dogs are commonly used for hunting feral swine, they are at high risk of exposure., Case Presentation: The following report describes the progression of pseudorabies infection in dogs in two states after exposure to feral swine. The first case occurred in a dog in Alabama after participation in a competitive wild hog rodeo. The second case occurred in multiple dogs in Arkansas after hunting feral swine, and subsequent consumption of the offal. The antibody prevalence of feral swine in the two states where the dogs were exposed is also examined., Conclusions: Dogs that are used for hunting feral swine are at high risk of exposure to pseudorabies because the disease is considered endemic in feral swine in the U.S.

Pseudorabies (PR), also known as Aujeszky's disease, is a highly contagious disease affecting pigs and a wide range of animals. Pseudorabies is enzootic in many countries. In China, it is a priority animal disease for control and eradication, however the data on disease frequency in intensive pig farms and the information on associated risk factors is inadequate. A cross-sectional study of intensive pig farms (≥350 sows) in Shanghai was conducted to determine herd-level prevalence of PRV and associated risk factors. Following a two-stage random sampling design, a total of 1349 sow serum samples were tested by gpI-ELISA from a total of 91 intensive pig farms in Shanghai. A herd was classified as positive if at least one PRV test-positive sow was present. Information on putative risk/protective factors was collected using questionnaires to pig farm owners or veterinarians. A logistic regression model was built to identify risk/protective factors for herd positivity. The results indicated that the herd-level true prevalence was 67.6% (95% CI：57.0-77.0). In the multivariable logistic regression model using backward stepwise procedure, two risk factors were found to be significantly associated with herd positivity: 'Breeding with introduced sows in the last 12 months' (OR = 3.5, 95%CI:1.2, 10.3) and 'Presence of stray dogs or cats' (OR = 4.0, 95%CI: 1.2, 12.6). The multivariable logistic model fitted the data well. Hosmer-Lemeshow goodness of fit test showed χ 2  = 10.86 (df = 8, p =  0.21 > 0.05) and the predictability (area under the ROC curve) was 0.86. This study suggested that PR was highly endemic in intensive pig farms in Shanghai. The risk and protective factors identified in this study could be useful to improve the prevention policy of PR in Shanghai and other areas of China., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Pseudorabies (PR) has been prevalent in Chinese swine breeding farms since the outbreak at the end of 2011. For investigating current prevalence of PR, a nationwide surveillance has been performed in this study. The swine serum samples were collected from 93, 100, 92, and 91 swine farms in China during 2013-2016, respectively. Since the extensive use of gE-deleted pseudorabies virus (PRV) vaccine, we could apply the PRV-gE antibody for determining wild-type virus infection and the PRV-gB antibody for evaluating vaccine immunization. The results were concluded as follows: (1) Nationally, the positive rate of PRV-gB was maintained at a high level (> 90%), while the positive rate of PRV-gE continued to decrease (from 22.17 to 13.14%). (2) The positive rates of PRV-gE were greatly varied in different geographical regions and swine farms (0~100%), while the positive rate of PRV-gB was generally high (> 90%). (3) The number of imported PRV attenuated vaccines were about twice that of domestic PRV attenuated vaccines, while the positive rate of PRV-gB was not significantly different (P > 0.05). (4) The performance of PR eradication developing or developed farms was better than the performance of common farms, with higher positive rate of PRV-gB (> 90%) and much lower positive rate of PRV-gE (nearly 0%).

Background: Aujeszky's disease virus (ADV) can cause neurologic disease in young pigs, respiratory disease in older pigs and abortion or birth of mummified fetuses or stillborn neonates. The re-emergence of Aujeszky's disease (AD) in pig farms vaccinated with live vaccine (Bartha-K61) caused substantial economic losses to Chinese pig industry since late 2011. A field ADV, named Qihe547, was isolated from pigs that exhibited suspected AD clinical symptoms. To better understand the genetic characteristics and mutations of Qihe547 ADV, the whole genome was sequenced and analyzed., Results: The genomic length of Qihe547 ADV was 143,404 bp, with 73.59% G + C contents. Phylogenetic analysis based on the whole genome of ADV strains revealed that Chinese ADV strains were located to one group with three subgroups. Qihe547 ADV was closely related to these novel ADV strains isolated in China since 2012. Qihe547 presented numerous hypervariable regions compared with oversea ADV strains. In 34 genes of Qihe547 ADV, amino acid (AA) insertion or deletion were observed. In addition, numerous AA mutations were found in the main protective antigen genes (gB, gC and gD genes). The differences of potential antigenic peptides in the main protective antigens between Qihe547 ADV and ADV Bartha were discovered in the dominant antigenic regions of gB (AA59-AA126, AA507-AA734),the extracellular region of gC and gD., Conclusion: High diversity was observed between Qihe547 and foreign ADV isolates. The AA variations and the differences of potential antigenic peptides in the important functional regions of the main protective antigen (gB, gC and gD) of ADV Qihe547 may contribute to immune evasion of the virus and may be partial reason that the virus escapes from the vaccination of Bartha-K61 vaccine. In a word, the effect of the variations obviously requires further research.

In late 2011, a variant pseudorabies virus (vPRV) emerged in Bartha-K61-vaccinated pig herds, resulting in high morbidity and mortality of piglets in China. Since 2013, the autopsy lesions, histological examinations, virus isolation, phylogenetic analysis and selection pressure analysis of the gE gene of vPRV were recorded for 395 clinical cases, and 5,033 pig serum samples were detected by PRV gE-coated enzyme-linked immunosorbent assay. The major clinical symptoms were abortion in pregnant sows, fatal neurological signs in piglets and respiratory disease in growing pigs. Necrotic splenitis, hepatitis and lymphadenitis, haemorrhagic nephritis and non-suppurative encephalitis were observed by histopathological examination. Typical eosinophilic inclusion bodies were found in the nuclei of liver cells. Using PCR, 110 samples among 395 clinical cases tested positive for the gE gene. Fifteen vPRV strains were isolated and confirmed by sequencing and phylogenetic analysis of the gE gene. The strains shared 97.1%-99.9% nucleotide (nt) and 96.6%-99.5% amino acid (aa) homology with PRV reference strains. Selection pressure analysis showed that one site in the codons of glycoprotein E was under positive selection. Of the 5,033 serum samples, 2,909 were positive by ELISA for a positive rate of 57.8%. These results showed that vPRV was still prevalent in Shandong Province, indicating severe PRV infectious pressure. The preparation of new vaccines against PRV is extremely urgent., (© 2018 Blackwell Verlag GmbH.)

An outbreak of a highly virulent pseudorabies virus strain, ZJ01, occurred in PRV-vaccinated pigs in China in 2011. In this study, ZJ01 caused fatal diseases, while the Chinese prototypic PRV strain LA caused mild respiratory disorders. Full-genome sequencing results indicate the two viruses can be classified into two sub-clusters that distinct from traditional European and US strains. To examine the potential role of the gE and gI proteins in ZJ01 virulence, we generated several recombinant viruses. In two chimeric viruses (rZJ01-LA/gEI and rLA-ZJ01/gEI), the gE and gI genes were swapped using corresponding genes from ZJ01 and LA. rZJ01-LA/gEI and the parental virus rZJ01 retained high virulence in piglets, although the survival time for rZJ01-LA/gEI infected piglets was obviously prolonged. In contrast, rLA-ZJ01/gEI exhibited higher virulence than its parental virus rLA. We conclude that changes in gE and gI proteins partly contribute to the enhanced virulence of ZJ01 strain., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Pseudorabies (PR) is an important emerging infectious disease that is characterized by fever, extreme itching and encephalomyelitis. However, it is still unclear whether Tibetan pigs are exposed to Pseudorabies virus (PRV) or not. The present study was conducted to investigate the seroprevalence of PRV infection in Tibetan pigs in Nyingchi area of Tibet through enzyme-linked immunosorbent assay (ELISA). A total of 368 serum samples from Tibetan pigs were collected during 2015., Results: Results showed that 58 (15.76%) samples were found positive for PRV antibodies with further distribution of 18.23%, 13.42% and 6.25% from Nyingchi, Mainling and Gongbo'gyamda areas on the Tibetan plateau, respectively; along with 12.10%, 17.71% and 17.57% prevalence of PRV in juveniles, sub-adults and adults, respectively. The prevalence of PRV infection between male (14.61%) and female (16.84%) showed non-significant difference (P > 0.05). The risk factors of infection were found to be associated with feed type, age and altitude., Conclusions: The present study depicts a serious concern with a new emerging infectious disease in Tibetan pigs in Tibet, China.