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African swine fever (ASF) is a rapidly fatal viral haemorrhagic fever in Chinese domestic pigs. Although very high mortality is observed in pig farms after an ASF outbreak, clinically healthy and antibody-positive pigs are found in those farms, and viral detection is rare from these pigs. The ability of pigs to resist ASF viral infection may be modulated by host genetic variations. However, the genetic basis of the resistance of domestic pigs against ASF remains unclear. We generated a comprehensive set of structural variations (SVs) in a Chinese indigenous Xiang pig with ASF-resistant (Xiang-R) and ASF-susceptible (Xiang-S) phenotypes using whole-genome resequencing method. A total of 53,589 nonredundant SVs were identified, with an average of 25,656 SVs per individual in the Xiang pig genome, including insertion, deletion, inversion and duplication variations. The Xiang-R group harboured more SVs than the Xiang-S group. The F-statistics ( F ST ) was carried out to reveal genetic differences between two populations using the resequencing data at each SV locus. We identified 2,414 population-stratified SVs and annotated 1,152 Ensembl genes (including 986 protein-coding genes), in which 1,326 SVs might disturb the structure and expression of the Ensembl genes. Those protein-coding genes were mainly enriched in the Wnt, Hippo, and calcium signalling pathways. Other important pathways associated with the ASF viral infection were also identified, such as the endocytosis, apoptosis, focal adhesion, Fc gamma R-mediated phagocytosis, junction, NOD-like receptor, PI3K-Akt, and c-type lectin receptor signalling pathways. Finally, we identified 135 candidate adaptive genes overlapping 166 SVs that were involved in the virus entry and virus-host cell interactions. The fact that some of population-stratified SVs regions detected as selective sweep signals gave another support for the genetic variations affecting pig resistance against ASF. The research indicates that SVs play an important role in the evolutionary processes of Xiang pig adaptation to ASF infection.

Mosquitoes (Diptera: Culicidae) are one of the most studied groups of arthropods worldwide due to their high transmission capacity for pathogens, including viruses and parasites. During June to October 2022, the prevalence of mosquito species in 12 intensive pig farms from 12 representative administrative regions in Hunan province of China was investigated using traps with ultraviolet light. All collected mosquitoes were counted and identified to species according to morphological and molecular methods. A total of 4,443 mosquito specimens were collected in the pig farms, and they represented one family, four genera and nine species. Culex pipiens pipiens (24%) was the most common mosquito species, followed by Armigeres subalbatus (23.4%) and Culex tritaeniorhynchus (20.6%). Phylogenetic analyses based on mitochondrial cox1 sequences revealed all mosquito species from present study grouping into distinct monophyletic groups corresponding to nine known mosquito species with strongly supported. The results of the present investigation have implications for the ongoing control of mosquito infestation in pig farms in Hunan province, China. This is the first report of mosquito populations in intensive pig farms in Hunan province, China., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The multifaceted behavioral and ecological flexibility of pigs and wild boar (Sus scrofa) makes study of their domestication both complex and of broad anthropological significance. While recognizing contextual contingency, we propose several "pathways" to pig domestication. We also highlight the diversity of pig management practices. This diversity complicates zooarchaeological detection of management techniques employed by humans in the early steps of domestication, and we stress the need for multiple lines of evidence. Drawing together the evidence, we review early Holocene human–Sus relations in Japan, Cyprus, northern Mesopotamia, and China. Independent pig domestication occurred in northern Mesopotamia by c. 7500 cal. BC and China by c. 6000 cal. BC. In northern Mesopotamia pig domestication followed a combined "commensal and prey" pathway that evolved into loose "extensive" husbandry that persisted as the dominant form of pig management for several millennia. There are not yet enough zooarchaeological data to speculate on the early stages of pig domestication in China, but once that process began, it involved more intensive management (relying on pens and fodder), leading to more rapid selection for phenotypes associated with domestication. Finally, pig domestication "failed" to take off in Japan. We suggest this was related to a number of factors including the lack of domestic crops and, potentially, cultural barriers to conceiving animals as property. [ABSTRACT FROM AUTHOR]

Introduction of African swine fever (ASF) to China in mid-2018 and the subsequent transboundary spread across Asia devastated regional swine production, affecting live pig and pork product-related markets worldwide. To explore the spatiotemporal spread of ASF in China, we reconstructed possible ASF transmission networks using nearest neighbour, exponential function, equal probability, and spatiotemporal case-distribution algorithms. From these networks, we estimated the reproduction numbers, serial intervals, and transmission distances of the outbreak. The mean serial interval between paired units was around 29 days for all algorithms, while the mean transmission distance ranged 332 -456 km. The reproduction numbers for each algorithm peaked during the first two weeks and steadily declined through the end of 2018 before hovering around the epidemic threshold value of 1 with sporadic increases during 2019. These results suggest that 1) swine husbandry practices and production systems that lend themselves to long-range transmission drove ASF spread; 2) outbreaks went undetected by the surveillance system. Efforts by China and other affected countries to control ASF within their jurisdictions may be aided by the reconstructed spatiotemporal model. Continued support for strict implementation of biosecurity standards and improvements to ASF surveillance is essential for halting transmission in China and spread across Asia.

Change strategies, and the eventual abandonment of semi-domesticated and domesticated Sus scrofa is discussed in regards to increasing regional aridity in both the ancient Levant and what is now northwest China between 8,000 BP and 4,000 BP. A review of literature suggests a changing agroecological role of pigs, from one closely linked to production in the local ecosystem to one closely linked to production in the human social system as drying conditions created more favourable conditions for grain agriculture. The eventual abandonment of pigs as a viable agroecosystem component is discussed. [ABSTRACT FROM AUTHOR]

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) causes porcine reproductive and respiratory syndrome (PRRS), leading to abortion in sows and respiratory distress in breeding pigs. In China, PRRSV1 and PRRSV2 are the two circulating genotypes in swine herds, with distinct virulence. PRRSV2 further consists of classical (C-PRRSV2), highly pathogenic (HP-PRRSV2), and NADC30-Like (N-PRRSV2) subtypes. The diversity of PRRSV poses challenges for control and eradication, necessitating reliable detection assays for differentiating PRRSV genotypes., Methods: A new TaqMan-based RT-qPCR assay with four sets of primers and probes targeting conserved regions of the ORF7 and NSP2 genes of PRRSV was developed, optimized, and evaluated by us. Reaction conditions such as annealing temperature, primer concentration, and probe concentration were optimized for the assay. Specificity, sensitivity, repeatability, stability, limit of detection (LOD), concordance with the reference method were evaluated for the assay., Results: The assay could detect and type PRRSV1, C-PRRSV2, HP-PRRSV2, and N-PRRSV2 simultaneously with 97.33% specificity, 96.00% sensitivity, 12 copies/μL LOD, 97.00% concordance with reference assays. We applied the assay to 321 clinical samples from swine farms in China. The assay successfully detected and typed 230 PRRSV-positive samples, with 24.78% (57/230) of them further confirmed by ORF5 gene sequencing. The prevalence of PRRSV subtypes among the positive samples was as follows: C-PRRSV2 (15.22%), HP-PRRSV2 (23.48%), and N-PRRSV2 (61.30%). Two samples showed coinfection with different PRRSV subtypes., Conclusion: The quadruple RT-qPCR assay is a powerful tool for detecting and typing the currently circulating PRRSV strains in Chinese swine populations. It can assist in the surveillance of PRRSV prevalence and the implementation of prevention and control strategies.

Sus scrofa papillomatosis (SsP) is a tumour caused by Sus scrofa papillomaviruses (SsPVs). To investigate the presence of SsPVs in China, 354 domestic pig skin samples collected from Guangxi Province were examined for SsPV DNA by PCR. Three SsPV1s (GX12, GX14, and GX18) were identified with a prevalence of 0.847% (3/354). Sequence analysis showed that L1 of SsPV1/GX12 and SsPV1/GX14 had 99.7% and 99.6% nucleotide identify with the reference SsPV1a, respectively. Phylogenetic and evolutionary analyses showed that SsPV1/GX12 and SsPV1/14 clustered into SsPV1a and that SsPV1/GX18 clustered into SsPV1b. Compared with other SsPV L1 and L2 proteins, we found that the SsPV1/GX18 and SsPV1b strains shared the same unique substitutions, and SsPV1/GX12, SsPV1/GX14, and SsPV1a shared almost identical amino acid sequences. This study reports the first detection of SsPV DNA in China based on whole genome information and provides a scientific basis for the development of SsPV pathogenic biology, epidemiology, and prevention, as well as control technology research., (© 2023. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

The phylum Microsporidia encompasses a diverse group of obligate, intracellular, and spore-forming organisms able to infect a wide range of animal hosts. Among them, Enterocytozoon bieneusi is the most frequently reported species in humans and animals. Little is known about the presence and epidemiology of E. bieneusi in wildlife. We investigated E. bieneusi occurrence and genetic diversity in wild and domestic mammals, through molecular-detection methods, from different regions across Portugal. A total of 756 samples were collected from 288, 242, and 226 wild carnivores, wild ungulates, and domestic animals, respectively. Overall, eight specimens were E. bieneusi-positive (1.1%, 8/756) obtained from five wild (Iberian lynx, Iberian wolf, red fox, stone marten, and wild boar) and one domestic (sheep) host. Nucleotide sequence analysis identified four genotypes of E. bieneusi, Type IV, Wildboar3, BEB6, and PtEbIX. Three of those genotypes belong to Groups 1 (Type IV and Wildboar3) and 2 (BEB6), which are known to contain genotypes capable of infecting a variety of hosts, including humans, highlighting their public health importance. PtEbIX belongs to the dog-specific Group 11. This study represents the first, largest, and most comprehensive molecular-based epidemiology survey carried out in Portugal in wild and domestic animals to date and the first worldwide identification of E. bieneusi in wolf species. Our study showed that wild carnivores and ungulates may act as reservoirs of zoonotic genotypes of E. bieneusi, establishing their role in maintaining the sylvatic cycle of this parasite while representing a potential source of infection for humans and domestic animals., (© The Author(s) 2023. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Giardia duodenalis is a common intestinal protozoan that can cause diarrhea and intestinal disease in animals and in humans. However, the prevalence and assemblages of G. duodenalis in pigs from Guangxi Zhuang Autonomous Region have not been reported. In this study, a total of 724 fecal samples (201 from nursery pigs, 183 from piglets, 175 from breeding pigs, and 165 from fattening pigs) were obtained in four areas of the region (Nanning, Yulin, Hezhou, and Guigang). The gene of the small subunit ribosomal RNA (SSU rRNA) of G. duodenalis was amplified by nested PCR. The results show that the prevalence of G. duodenalis in pigs was 3.59% (26/724), of which 14 samples belonged to assemblage A (53.85%) and 12 samples belonged to assemblage E (46.15%). The infection rates of G. duodenalis in Hezhou, Yulin, Nanning, and Guigang were 0%, 0.7%, 10.8% and 1.1%, respectively (χ 2  = 45.616, p < 0.01); whereas 5.1% of breeding pigs, 6.0% of piglets, 2.4% of fattening pigs, and 1.0% of nursery pigs were infected with G. duodenalis (χ 2  = 8.874, p < 0.05). The SSU rRNA-positive samples were amplified by PCR based on the β-giardin (bg), glutamate dehydrogenase (gdh), and triphosphate isomerase (tpi) genes. Ten, eight and seven positive samples were detected, respectively. Based on phylogenetic analysis of the three genetic loci sequences, a multilocus genotyping A1 was found. The findings of this study provide basic data for the development of prevention and control of G. duodenalis infections in pigs and humans in the Guangxi Zhuang Autonomous Region., (© Y.-F. Song et al., published by EDP Sciences, 2023.)

Hepatitis E virus (HEV) causes infections in humans and a wide range of animal hosts. Wild boar is an important natural reservoir of HEV genotypes 3−6 (HEV-3−HEV-6), but comparative analysis of HEV infections in both feral and farmed wild boars remains limited. In this study, samples from 599 wild boars were collected during 2017−2020, including 121 feral wild boars (collected 121 fecal, 121 serum, and 89 liver samples) and 478 farmed wild boars (collected 478 fecal and 478 serum samples). The presence of anti-HEV IgG antibodies were detected by the HEV-IgG enzyme-linked immunosorbent assay (ELISA) kit. HEV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR), targeting the partial ORF1 genes from fecal and liver samples, and the obtained genes were further genotyped by phylogenetic analysis. The results showed that 76.2% (95% CI 72.1−79.9) of farmed wild boars tested anti-HEV IgG seropositive, higher than that in feral wild boars (42.1%, 95% CI 33.2−51.5, p < 0.001). HEV seropositivity increased with age. Wild boar HEV infection presented a significant geographical difference (p < 0.001), but not between sex (p = 0.656) and age (p = 0.347). HEV RNA in fecal samples was detected in 13 (2.2%, 95% CI 1.2−3.7) out of 599 wild boars: 0.8% (95% CI 0.0−4.5, 1/121) of feral wild boars and 2.5% (95% CI 1.3−4.3, 12/478) of farmed wild boars. Phylogenetic analysis showed that all these viruses belonged to genotype HEV-4, and further grouped into sub-genotypes HEV-4a, HEV-4d, and HEV-4h, of which HEV-4a was first discovered in the wild boar populations in China. Our results suggested that farms could be a setting for amplification of HEV. The risk of HEV zoonotic transmission via rearing and consumption of farmed wild boars should be further assessed.

African swine fever (ASF) is a hemorrhagic and fatal disease of domestic pigs and wild boars caused by the African swine fever virus (ASFV). There is neither effective treatment nor vaccine at present, and thus this disease has led to major economic losses and adverse impacts on the livelihoods of stakeholders involved in the pork food system in China. In this study, a multi-criteria decision analysis (MCDA) method based on a geographic information system (GIS) was used to identify suitable areas for ASF occurrence in China. Ten spatial risk factors regarding ASF epidemic in China were identified from literature reviews, and the relative importance between them was evaluated by experts based on a pairwise comparison matrix. A numerical weight was calculated for each risk factor using an analytic hierarchy process (AHP) based on the evaluated results. The corresponding geographic data were collected, according to the hypothetical relationship between each factor and the suitability for ASF occurrence, risk factors were converted to standardized geographical layers using suitability relationship and then were combined using a weighted linear combination (WLC) method to produce a map of suitability for ASF occurrence. The results showed that our map has good accuracy in predicting the hot- spots of ASF in China (AUC =0.791; 95% CI [0.741-0.852]). In conclusion, our study provides decision-making aid support for Chinese veterinary services to implement African swine fever surveillance and control measures., 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 © 2022 Elsevier B.V. All rights reserved.)

Community attitudes towards large carnivores are of central importance to their conservation in human-dominated landscapes. In this study, we evaluate community attitudes and perceptions towards the Amur tiger (Panthera tigris altaica), Amur leopard (Panthera pardus orientalis) and bears (Ursus thibetanus and Ursus arctos), as well as their prey species, namely sika deer (Cervus nippon), roe deer and wild boar (Sus scrofa), in Yanbian Korean Autonomous Prefecture, Jilin province, northeast China. We surveyed 139 households and found that community members' perceptions of large carnivores and their prey species were influenced by their predominant economic activities; their prior interactions with wildlife; their household income level; and whether they were either long-term residents of Yanbian or had migrated to the region from elsewhere in China. We recorded fairly neutral attitudes towards large carnivores among the communities we surveyed, but strongly negative attitudes were shown towards wild boar, particularly where respondents had lost agricultural products to crop raiding by wild boar. We recommend conservation stakeholders in northeast China utilise this finding to encourage support for large carnivore recovery and conservation by targeting messaging around the importance of the tiger as a key predator of wild boar in the ecosystem. Furthermore, our findings suggest that government provided compensation paid for cattle lost to large carnivore predation (notably, by tigers) may be helping to reduce animosity from cattle owners towards large carnivores. However, we also highlight that compensation for loss of livestock is therefore performing a useful role in mitigating human-wildlife conflict, that there are potentially unintended consequences of the current compensation program, for example it fails to dissuade livestock grazing in protected areas., Competing Interests: The funders for our research had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript and the authors declare no conflict of interest.

Porcine epidemic diarrhea (PED) caused by porcine epidemic diarrhea virus (PEDV) is one of the most devastating diseases in the global pig industry due to its high mortality rate in piglets. Maternal vaccines can effectively enhance the gut-mammary gland-secretory IgA axis to boost lactogenic immunity and passive protection of nursing piglets against PEDV challenge. From 2017 to 2021, we collected 882 diarrhea samples from 303 farms in China to investigate the epidemiology of PEDV. The result showed that about 52.15% (158/303) of the farms were positive for PEDV with an overall detection rate of 63.95% (564/882) of the samples. The S1 fragments of S gene from 104 strains were sequenced for the phylogenetic analysis. A total of 71 PEDV strains (68.27%) sequenced in this study were clustered into the predominant G2c subgroup, while the newly-defined G2d strains (9.62%) were identified in three provinces of China. The NH-TA2020 strain of G2c subgroup was isolated and cultured, and its infection to piglets caused watery diarrhea within 24 ​h, indicating its strong pathogenicity. Oral administration of NH-TA2020 strain to pregnant gilts stimulated high levels of IgA antibody in colostrum. The piglets fed by the gilts above were challenged with NH-TA2020 strain or CH-HeB-RY-2020 strain from G2d subgroup, and the clinical symptoms and virus shedding were significantly reduced compared to the mock group. Our findings suggest that G2c subgroup is the predominant branch circulating in China from 2017 to 2021. Oral administration of NH-TA2020 enhances maternal IgA and lactogenic immune responses, which confer protection against the homologous and emerging G2d PEDV strains challenges in neonates., (Copyright © 2022 The Authors. Publishing services by Elsevier B.V. All rights reserved.)

Porcine circovirus type 4 (PCV4), a unique circovirus with a different classification from other existing circovirus, was discovered in domestic pigs in several provinces of China. In this study, in order to investigate the epidemiology and genetic diversity of PCV4 in wild boars (Sus scrofa), a total number of 138 wild boar samples were collected from five different areas in Jiangxi Province of China, between January 2020 and December 2020. Taqman based real-time PCR were used to test PCV4 as well as PCV1, PCV2, and PCV3. Among 138 samples, 30 samples (21.7%) were positive for PCV1, 31 samples (22.5%) were positive for PCV2, 8 samples (5.8%) were positive for PCV3 and 27 samples (19.6%) were positive for PCV4, respectively. Some of the samples were co-infected with multiple PCVs. In this study, we successfully sequenced the complete genome of two PCV4 strains, which shared 98.5-99.8% of their genomic nucleotide similarity with the other five PCV4 strains discovered in domestic pigs. Phylogenetic analysis showed that the two PCV4 strains derived from wild boars were located in a closed relative branch with other PCV4 strains derived from domestic pigs, but were distinguished from other circovirus. These results of this study not only expand our understanding of the prevalence of PCVs, especially PCV4, in wild boars in Jiangxi province of China, but also showed the molecular epidemiology of PCV4. Nevertheless, the impact of wild boars infected with PCV4 on intensive farmed pigs industry remains to be further explored., Competing Interests: Conflict of interest The authors declare that they have no conflict interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Microsporidia comprises a diverse group of obligate, intracellular, and spore-forming parasites that infect a wide range of animals. Among them, Enterocytozoon bieneusi is the most frequently reported species in humans and other mammals and birds. Data on the epidemiology of E. bieneusi in wildlife are limited. Hence, E. bieneusi was investigated in eight wild ungulate species present in Spain (genera Ammotragus, Capra, Capreolus, Cervus, Dama, Ovis, Rupicapra, and Sus) by molecular methods. Faecal samples were collected from free-ranging (n = 1058) and farmed (n = 324) wild ungulates from five Spanish bioregions. The parasite was detected only in red deer (10.4%, 68/653) and wild boar (0.8%, 3/359). Enterocytozoon bieneusi infections were more common in farmed (19.4%, 63/324) than in wild (1.5%, 5/329) red deer. A total of 11 genotypes were identified in red deer, eight known (BEB6, BEB17, EbCar2, HLJD-V, MWC&#95;d1, S5, Type IV, and Wildboar3) and three novel (DeerSpEb1, DeerSpEb2, and DeerSpEb3) genotypes. Mixed genotype infections were detected in 15.9% of farmed red deer. Two genotypes were identified in wild boar, a known (Wildboar3) and a novel (WildboarSpEb1) genotypes. All genotypes identified belonged to E. bieneusi zoonotic Groups 1 and 2. This study provides the most comprehensive epidemiological study of E. bieneusi in Spanish ungulates to date, representing the first evidence of the parasite in wild red deer populations worldwide. Spanish wild boars and red deer are reservoir of zoonotic genotypes of E. bieneusi and might play an underestimated role in the transmission of this microsporidian species to humans and other animals., (© The Author(s) 2022. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Hepatitis E virus (HEV), the causative agent of hepatitis E (HE), is classified into four major genotypes (1-4), with wild boar being the main natural reservoir for genotypes 3 and 4. However, little is known about the prevalence of HEV infection in wild boars in China. In this study, RT-nested PCR and RT-quantitative PCR were used to detect the HEV RNA in tissue samples taken from 331 free-ranging wild boars collected between 2018 and 2020 from 24 regions across China, and the partial ORF2 genes or complete genomes of the positive samples were sequenced. Furthermore, antibodies against HEV in 216 serum samples from wild boars were tested by ELISA. As a result, HEV RNA was detected in nine out of 331 liver samples of wild boars (2.72%), which were distributed in eight regions. Genetic and evolutionary analysis of partial ORF2 sequences indicated that the HEV strains identified in this study share 83.9%-100% nucleotide sequence identity and belong to subtypes 4d (n = 6), 4g (n = 2), and 4h (n = 1), and similar phylogeny was obtained using the complete genome sequences of seven wild boar HEV strains. Additionally, the HEV viral loads were higher in the liver than in other tissues and blood. Moreover, 61 out of 216 sera (28.2%) from wild boars tested positive for anti-HEV antibodies. To our knowledge, this is the first study to report the epidemiological situations of HEV infections in free-ranging wild boars in China, and the obtained data are valuable for prevention and control of HE., (© 2022 Wiley-VCH GmbH.)

Yimeng black pig is a national breed of geographical indication in China. The complete mitochondrial genome sequence of Yimeng black pig was first determined in this study (Accession number MN624263). The mitogenome (16,771 bp) consists of 22 tRNA genes, 13 protein-coding genes, 2 ribosomal RNA genes, and 1 control region (D-loop region). The complete mitochondrial genome sequence of the Yimeng black pig enriches data resource for further study in genetic mechanism and classification. [ABSTRACT FROM AUTHOR]

Numerous protist species are shared between humans and pigs. Among those, Giardia duodenalis, Cryptosporidium spp. and Balantioides coli have a clear public and animal health significance. For others such as Enterocytozoon bieneusi and Blastocystis sp., their impact on animal health has not been fully established. Little information is currently available on the molecular diversity of these protists in swine populations. To fill this gap, we molecularly assessed G. duodenalis, Cryptosporidium spp., B. coli, Blastocystis sp. and E. bieneusi in faecal samples from Iberian and Large White pigs raised under different (intensive and/or extensive) management systems in southern Spain. A total of 151 extensively raised Iberian pigs, 140 intensively raised Iberian pigs, and 184 intensively raised Large White pigs were investigated. Blastocystis sp. was the agent most prevalently found (47.8%), followed by B. coli (45.5%), G. duodenalis (10.7%), E. bieneusi (6.9%), and Cryptosporidium spp. (5.5%). Blastocystis sp. was significantly less prevalent in intensively raised Iberian pigs (22.9%) than in their extensively raised counterparts (51.0%) or in intensively raised Large White pigs (64.1%). A significantly higher prevalence was found for G. duodenalis, Cryptosporidium spp., and E. bieneusi in Large White pigs than Iberian pigs. Balantioides coli was similarly distributed (40.0-51.1%) in all three investigated swine populations. Sequence analyses revealed the presence of G. duodenalis assemblage E, two Cryptosporidium species (Cryptosporidium scrofarum and Cryptosporidium suis), B. coli (genotypes A and B), Blastocystis sp. (ST1, ST3, and ST5), and E. bieneusi (EbpA, EbpC, EbpD, O, and a novel genotype named PigSpEb2). Novel genotype PigSpEb2 was found alone or in combination with EbpA. Data suggest a widespread exposure to protist enteroparasites in domestic pig populations irrespectively of breed and raising management system. Many of the species/genotypes identified have a zoonotic potential and might represent a public health concern., (© 2021 Wiley-VCH GmbH.)

Mitochondrial cytochrome b (Cytb) and partial control region (CR) DNA sequence of 165 individuals out of eight pig breeds (Laiwu Black, Dapulian Black, Licha Black, Yimeng Black, Yantai Black, Wulian Black, Luyan White and Changwei White) from Shandong province of China were sequenced to determine phylogenetic relationships and to what extent they were affected by modern commercial breeds (Landrace, Yorkshire and Duroc) in maternal lineage. The eight breeds from Shandong had lower maternal evolutionary divergence than the three commercial breeds. Additionally, they shared the same haplotype (T2) of Cytb. All these results suggest they may have originated from closely related maternal ancestors, if not from a single ancestor. The fact that haplotypes of Dapulian Black and Laiwu Black formed their own subclades, while those of other breeds of Shandong dispersed in the Asian clade of the tree based on CR, indicates that Dapulian Black and Laiwu Black are indigenous breeds with relatively independent maternal lineage, while the others have extensively gene flow with other breeds. Except in Luyan White, no European haplotypes were found in pig breeds from Shandong, demonstrating the maternal introgression from the modern commercial pigs has had no or very little impact on the breeds from Shandong. Comparatively, CR is more suitable to analyze the phylogenetic relationships of closely related groups, whereas the four SNPs of Cytb are useful to determine whether modern commercial breeds (Duroc, Landrace and sometimes Yorkshire) were used as dam in the breeding process of new breeds or synthetic lines in China. [ABSTRACT FROM AUTHOR]

Pigs are one of several host species for Toxoplasma gondii, and consumption of infected pork may lead to toxoplasmosis in humans. The aim of this study was to develop an indirect enzyme-linked immunosorbent assay (ELISA) using surface antigen protein 1 (SAG1) of T. gondii for the diagnosis of porcine toxoplasmosis and to perform a serological investigation of pigs in Shandong province, China. A total of 1170 serum samples were collected from 14 cities, and 244 of them (20.85%) were positive. In different areas, the prevalence ranged from 15.63% to 22.98%, which had a significant differentiation. Among the different populations, gestating sows had the highest seroprevalence (25.7%), followed by breeding boars (22.7%), replacement gilts (21.1%), fattening pigs (18.3%) and piglets (17.1%). The rearing environment was also a determinant of seroprevalence, including family farmers (25.5%), large farmers (15.2%) and small farms (22.8%). This study provides information on the seroepidemiological study of T. gondii in pigs in Shandong province, which will be useful in developing strategies for the control of T. gondii infection in pigs., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Piglet mortality is an economically important complex trait that impacts sow prolificacy. Genetic analyses for piglet mortality at weaning have been reported in dozens of studies, but not for piglet mortality at birth. In this study, we used multi-breed data sets from Yorkshire, Landrace, and Duroc sows to characterize the genetic fundamentals of piglet mortality at birth. The heritabilities from parity I to III were estimated to be 0.0630, 0.1031, and 0.1140 respectively. By using a combined strategy, a total of 21 SNPs were detected in three parities, of which six were observed in parity I, five in parity II and 10 in parity III. Genome annotation revealed that these SNPs were harbored within or close to 19 candidate genes. The candidate genes were found to associate with the reproductive system and embryonic development in the tissue expression database, which are reasonably related to piglet mortality. These findings are expected to provide much information for understanding the genetic and genomic fundamentals of farrowing mortality., (© 2021 Stichting International Foundation for Animal Genetics.)

African swine fever (ASF) is mainly an acute hemorrhagic disease which is highly contagious and lethal to domestic pigs and wild boars. The global pig industry has suffered significant economic losses due to the lack of an effective vaccine and treatment. The African swine fever virus (ASFV) has a large genome of 170-190 kb, encoding more than 150 proteins. During infection, ASFV evades host innate immunity via multiple viral proteins. A528R is a very important member of the polygene family of ASFV, which was shown to inhibit IFN-β production by targeting NF-κB, but its mechanism is not clear. This study has shown that A528R can suppress the TLR8-NF-κB signaling pathway, including the inhibition of downstream promoter activity, NF-κB p65 phosphorylation and nuclear translocation, and the antiviral and antibacterial activity. Further, we found the cellular co-localization and interaction between A528R and p65, and ANK repeat domains of A528R and RHD of p65 are involved in their interaction and the inhibition of p65 activity. Therefore, we conclude that A528R inhibits TLR8-NF-κB signaling by targeting p65 activation and nuclear translocation.

Porcine circovirus type 2 (PCV2) is the causative agent of porcine circovirus-associated diseases (PCVAD), causing substantial economic losses to the swine industry worldwide. PCV3, as a recently discovered virus, is associated with porcine dermatitis, nephropathy syndrome, reproductive failure, congenital tremors, and other clinical symptoms. To further investigate the epidemic profile and genetic diversity of the two viruses, a total of 198 samples from swine at various growth stages suspected for PCVAD on 55 different pig farms between 2018 and 2020 were analyzed for presence of PCV2 and PCV3 by using a multiplex real-time PCR assay. Among the 198 samples, 113 (57.07%) and 72 (36.36%) were positive for PCV2 and PCV3 respectively, and 39 (19.7%) were positive for PCV2 and PCV3 co-infection. Subsequently, whole genome sequences of 34 PCV2 and 19 PCV3 strains were obtained from 30 and 19 clinical samples, respectively. Of these, 8 PCV2 strains belonged to PCV2a, 10 belonged to PCV2b and 16 belonged to PCV2d, indicating PCV2d was the predominant PCV2 genotype circulating in central China. Furthermore, co-infection of different PCV2 genotype strains was identified in three samples (JZ-4, KF-2 and JY-1), and a cross-recombination was found in the ORF2 region of the sequenced 13 PCV2d strains whose putative parental strains were LN6/1999 (MF278777) and MEX/41238/2014 (KT795287) strains. The phylogenetic analysis of PCV3 showed high nucleotide identity (>98%) among sequences obtained in this study and reference sequences. These data will aid our understanding of the molecular epidemiology and evolution of PCV2 and PCV3., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Porcine respiratory diseases remain the biggest challenge in pig-based food production and are a public health concern. Despite control measures, persistent outbreaks have been reported worldwide., Objective: To establish an early detection mechanism for pig farm disease outbreaks based on slaughterhouse risk and environmental assessment., Methods: We investigated the prevalence and risk factors of porcine respiratory disease-causing pathogens including Mycoplasma hyopneumoniae (MHP), porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV) and Haemophilus parasuis (HPS). Polymerase chain reaction (PCR) was used to analyse the lungs of 491 pigs from 19 slaughterhouses across 11 cities in Shanxi Province, China., Results: PCR detected MHP, PCV2, PPRSV and HPS in 76.99%, 67.00%, 11.82% and 19.55% of the samples, respectively; 10.12% were negative for all four pathogens. Co-positivity rates for two and three pathogens were identified. The results confirmed significant correlations between PCV2 and MHP (p = .001, p < .05), HPS and PCV2 (p = .01, p < .05) and MHP and PRRSV (p = .01, p < .05). No significant correlation was observed between HPS and MHP (p = .067, p > .05). Positive MHP and PCV2 rates were low in areas with high vegetation coverage. The overall pathogen positivity rate was higher in both lower and higher temperature environments., Conclusions: Interactions among pathogens may increase disease severity. Furthermore, environmental assessment and pathogen surveillance within pig slaughterhouses can be an effective approach for early detection and mitigation of new disease threats before broad dissemination occurs among a herd., (© 2021 The Authors. Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Chlamydia is a small gram-negative (G-) microorganism that can be dangerous to human and animals. In this study, we conducted a systematic review and meta-analysis of Chlamydia infection in swine in China. From PubMed, ScienceDirect, Chinese Web of knowledge (CNKI), VIP Chinese journal database, and Wanfang database, we collected a total of 72 publications reported in 1985-2020. The prevalence of Chlamydia was 22.48% in China. In the sampling year subgroup, the prevalence after 2011 was the highest (26.14%). In southern China, the prevalence was 30.97%. By contrast, the prevalence in northern China was only 10.79%. Also the difference was significant ( p  < 0.05). In the provincial level, Hubei had the highest rate of 36.23%. Boars had a higher prevalence (29.47%). The prevalence of Chlamydia detection in pigs with reproductive disorders (21.86%) was higher than that without reproductive disorders. Among the three age groups, finishing pigs (21.43%) had the highest prevalence. The prevalence in large-scale farmed pigs (28.58%) was the highest in the subgroup of feeding methods. The prevalence in farms was 24.29%, which was the highest in the survey areas. The prevalence in spring was the highest with 40.51%. Other methods had the highest prevalence (39.61%) than enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination assay. The prevalence of Chlamydia psittaci 18.41% was lower than the prevalence of Chlamydia abortus (41.35%). We also analyzed the impact of different climate factor subgroups (rainfall, temperature, and humidity) on the probability of pigs suffering from the disease. The results showed that Chlamydia was widespread in pigs in China. We suggest that we should strengthen the detection of Chlamydia in the semen of breeding pigs and pigs with reproductive disorders, and reasonably control the environment of large-scale pig farms, so as to reduce further infection of Chlamydia in pigs.

Senecavirus A (SVA), an emerging swine pathogen, has been reported in many provinces of China since the first outbreak in 2015 in Guangdong province. In this study, 10 lymph nodes positive for SVA, collected between 2018 and 2019 from slaughterhouses in Guangdong province, were subjected to virus isolation. Rapid and evident cytopathic effects (CPEs) were observed in SVA-infected PK-15 cells, including shrinking, rounding and detaching, with peak titers being reached at 24 h post infection (hpi). Electron microscopy showed that SVA particles are spherical and approximately 30 nm in diameter, and exist as crystalline lattices in cytoplasm revealed by ultra-thin sectioning. Phylogenetic analysis based on the whole genome sequences of all available isolates showed that SVA globally can be divided into two groups with each being further divided into two subgroups (Ia-b and IIa-b), and with the Guangdong isolates obtained here and other Chinese strains belonging to subgroups IIa and IIb. Evolutionary analysis showed that the mean substitution rate of SVA was 2.696 × 10 -3 per site per year based on whole genomic sequences, with subgroup IIb isolates having evolved faster than those of subgroup IIa. Analysis of efficient population size showed that the outbreak point of SVA worldwide occurred at the end of 2013 with that of subgroup IIb, the current dominant group, in mid 2014., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The clinical outcome of porcine circovirus 3 (PCV3) infection is still controversial. Herein, a novel PCV3 isolate (PCV3-China/DB-1/2017) with the molecular characterization of 24A and 27K in the Cap protein was used to inoculate three-week-old cesarean-derived, colostrum-deprived piglets. The nine PCV3 DB-1 inoculated piglets exhibited no obvious clinical symptoms or macroscopic lesions. PCV3 displayed a broad histotropism, including the heart, liver, spleen, lung, kidney, brain, lymph nodes, and tonsil, and the lungs and lymph nodes contained a higher quantity of viral genomes compared to that of the other organs. From 7 days after PCV3 DB-1 inoculation, the piglets showed obvious IgG antibody responses against PCV3 rCap-VLPs. The cumulative results demonstrated that PCV3 trend to low pathogenicity., Competing Interests: The authors declared no conflict of interest., (Copyright © 2021 Menghang Wang et al.)

African swine fever (ASF) is a highly contagious hemorrhagic viral disease of domestic and wild pigs. ASF has led to major economic losses and adverse impacts on livelihoods of stakeholders involved in the pork food system in many European and Asian countries. While the epidemiology of ASF virus (ASFV) is fairly well understood, there is neither any effective treatment nor vaccine. In this paper, we propose a novel method to model the spread of ASFV in China by integrating the data of pork import/export, transportation networks, and pork distribution centers. We first empirically analyze the overall spatiotemporal patterns of ASFV spread and conduct extensive experiments to evaluate the efficacy of a number of geographic distance measures. These empirical analyses of ASFV spread within China indicate that the first occurrence of ASFV has not been purely dependent on the geographical distance from existing infected regions. Instead, the pork supply-demand patterns have played an important role. Predictions based on a new distance measure achieve better performance in predicting ASFV spread among Chinese provinces and thus have the potential to enable the design of more effective control interventions.

To date, four species of porcine circoviruses (PCVs), including PCV1-4, have been reported to exist in the clinical cases. Fast and effective differential detection is critical to monitor the infection and co-infection status of PCVs for adopting reliable control strategies. However, currently available methods cannot simultaneously differentiate the four species of PCV strains. In this study, a quadruplex real-time PCR assay based on TaqMan probes was developed for differential detection of PCV1-4. The new quadruplex real-time PCR assay exhibited satisfied specificity, sensitivity, repeatability and reproducibility. In addition, the new assay was applied to the detection of 120 clinical samples collected from 2016 to 2020 in Jiangsu province of China and compared with previously reported PCV1-4 singleplex conventional PCR assays. Based on the clinical performance, the results from the quadruplex real-time PCR and conventional PCR assays showed 100% agreement. A total of 47 samples were detected as PCV positive by the quadruplex real-time PCR assay, including 1, 2, 1 samples were co-infected with PCV1 and PCV4, PCV2 and PCV3, PCV2 and PCV4, respectively. Full-length ORF2 sequencing and phylogenetic analysis supported the real-time PCR results that 5, 34, 8 and 4 of the 51 PCV sequences were PCV1, PCV2, PCV3 and PCV4, respectively. This study provides a promising alternative tool for rapid differential detection of PCVs and confirms the coexistence of all species of PCV1-4 strains in Jiangsu province in recent years., (© 2020 Wiley-VCH GmbH.)

Background: Blackened intestines in slaughtered pigs have been commonly observed in China in recent years. However, no cause has been reported., Objectives: We attempted to determine whether the blackening of the pig intestine was related to an excess of copper (Cu) in their feed., Methods: In this study, we observed and collected porcine intestines in small- and large-scale pig slaughterhouses in Shandong province from May to October 2018. Twelve types of metal ions were detected in the black intestinal samples., Results: The Cu level in the intestine samples was mostly higher than the Chinese national limit for food. Further study showed that Cu supplementation in most commercial porcine feed also exceeded the national standard. An animal model (mouse) that could mimic the intestinal blackening in pigs was established. Compared to control mice, Cu accumulated in the liver and intestines of mice fed an excessive Cu level, confirming the excessive Cu in the feed may be considered the major cause of blackened porcine intestines. Microscopic examination revealed that black intestines had many particles containing Cu in the lamina propria of the intestinal mucosa, and the intestinal mucosal epithelial cells showed degeneration and necrosis., Conclusions: In conclusion, overuse of Cu in animal feed can lead to animal poisoning and Cu accumulation in animal products. Such overuse not only harms the health of livestock but can also affect public health., Competing Interests: The authors declare no conflicts of interest., (© 2021 The Korean Society of Veterinary Science.)

Atypical porcine pestivirus (APPV) was identified and associated with congenital tremor (CT) type A-II in new born piglets and has been reported in many countries. In China, the first APPV identification in swine herds was reported in Guangdong province in 2016. To investigate the genetic characteristics of APPV in Guangxi province, 53 tissue samples from neonatal piglets with CT were collected and detected from October 2017 to May 2019. Five APPV strains which were named as GX04/2017, GX01-2018, GX02-2018, GX01-2019 and GX02-2019 were obtained. Sequence analysis revealed that all six APPV strains from Guangxi province, including five strains from this study and one from a previous report, shared 83.3%-97.5% nucleotide identity of complete genome and 91.7%-99.1% amino acid identity of the open reading frame (ORF), and shared 77.7%-97.7% nucleotide identity of complete genome and 90.6%-99.3% amino acid identity of ORF with reference strains. Phylogenetic analysis indicated that all APPV strains could be divided into three clades based on the complete genome, N pro , E rns and E2 gene sequences, respectively; and the APPV strains from Guangxi province distributed in two clades (clades I and II). No sign of recombination was observed from Guangxi strains. Evolution analysis performed on the complete genome of 58 APPV strains showed that America, Europe and Asia strains during 2006-2019 evolved at a mean rate of 1.37 × 10 -4 substitutions/site/year, and the most recent common ancestor (tMRCA) of them was estimated as 1,700.5 years ago. The findings of this study indicated that there existed a high degree of genetic diversity of APPV from Guangxi province, Southern China, which provided important information on the epidemiological features and evolutionary relationships of APPV., (© 2020 The Authors Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Recombinant lysostaphin has been used for the treatment of cow endometritis and mastitis in China. To our knowledge, no scientific effort has been made to evaluate the efficacy of lysostaphin in sows with clinical endometritis. Lysostaphin, loaded in effervescent tablets that were completely foamed and dissolved within 30 min in the presence of water or body fluids and released active lysostaphin, were administered vaginally on endometritis sows in this study. The clinical recovery, bacterial clearance and reproductive performance of sows with endometritis were investigated. We found that the 400U dosage (400U lysostaphin/pill/time, repeat once on the third day, a total of two times, with 10% oxytetracycline uterine injection as a control) is the most effective treatment. Staphylococcus aureus was the most prevalent finding (34%, n = 188), followed by Streptococcus (32%, n = 181), Escherichia coli (19%, n = 104) and other bacilli (15%, n = 83) before treatment by drugs. Administration of lysostaphin resulted in an extremely significant (p < .01) reduction in S. aureus (0.18 ± 0.25 from 4.57 ± 0.33) and Streptococcus (0.11 ± 0.14 from 3.88 ± 0.29), as well as a significant (p < .05) reduction in E. coli (0.55 ± 0.42 from 3.11 ± 0.14). Mixed infections (83%) were predominant before treatment, in contrast to single infections (61%) after treatment. Large-scale trials were conducted to verify the clinical efficacy of lysostaphin on sow endometritis. The average cure rate of 400u lysostaphin on sow endometritis(82.5%) was higher than the antibiotic group(72.17%). In addition, our results revealed that intravaginal administration of lysostaphin had no adverse effect on the reproductive performance of sows. Thus, this lysostaphin has potential application value as a new method alternative to antibiotics to treat endometritis in sows., (© 2020 The Authors. Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Swine erysipelas is a common infectious disease that affects the pig-breeding industry. The purpose of this study was to elucidate the risk factors and their role in the prevalence of swine erysipelas so that one may be able to better prevent and control the swine erysipelas outbreaks in Northeast China. Using spatial clusters, the study area was divided into two parts: South Central Mainland China (hot spots) and Northeast Mainland China (potential outbreak areas). We investigated a total of 31 environmental factors and used the lasso regression and k-fold cross-validation methods to determine the main factors involved. Seven risk factors were determined to have a major impact on swine erysipelas. Multiple logistic regression was used to examine the contribution of these seven risk factors to the outbreak from 2008 to 2018, in the two research regions. In South Central Mainland China, where swine erysipelas was most prevalent, the extreme maximum temperature [OR = 1.143 (95%CI: 1.032-1.342)], total precipitation [OR = 2.298 (95%CI: 1.410-5.112)] and precipitation ≥0.1 mm [OR = 2.396 (95%CI: 1.329-5.941)] exhibited positive effects. The maximum wind speed [OR = 0.550 (95%CI: 0.303-0.775)] and concentration of O3-8H-90 per [OR = 0.876 (95%CI: 0.747-0.980)] exhibited negative effects. Summer was the main season for the erysipelas epidemic in South Central Mainland China. In Northeast China, only the total precipitation [OR = 1.048 (95%CI: 0.900-0.989)] was positively correlated with the prevalence of swine erysipelas, whereas the other factors were not significant. There was no obvious seasonal feature for the epidemic. Through the comparison and analysis of risk factors between the two research regions, more attention should be given to the impacts of high temperature and precipitation on the swine erysipelas epidemic in Northeast China., (© 2020 Wiley-VCH GmbH.)

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically devastating viral diseases in the global pig industry, including China. Recently, we successfully isolated a porcine reproductive and respiratory syndrome virus (PRRSV) from lung tissue and peripheral blood of piglets at a farm from Dujiangyan in Sichuan, China, and named it the DJY-19 strain. The full-length genome sequence of DJY-19 shared 86.8%-94.1% nucleotide similarity with NADC30-like and NADC30 PRRSV strains. We compared the open reading frame (ORF) 5 gene of DJY-19 with 34 PRRSV strains from Genbank. Phylogenetic analysis showed that DJY-19 clustered with NADC30 strains, characterized by a predicted 131-amino-acid deletion in the nonstructural protein (NSP) 2. The results of homology analysis showed that the homology between DJY-19 and NADC30 (JN654459.1) strains was the highest (95.9%), whereas homology with other domestic strains was lower (80.9%-92.6%). Furthermore, we identified four recombination breakpoints in the DJY-19 genome; they separated the DJY-19 genome into four regions. The 8106-9128 nucleotide (nt) region of DIY-19 was highly similar to the TJ strain, and the 12106-12580 nt region of DIY-19 was highly similar to the JXA1-R strain. Our findings demonstrate that DJY-19 arose from the recombination of North America NADC30 strain and TJ strain and JXA1-R in China. The application of multiple attenuated vaccine strains has led to complex recombination of PRRSV strains in China. This study provides a theoretical basis for making a more reasonable PRRS virus control and prevention strategy., (© 2020 The Authors Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Cryptosporidium is an important zoonotic parasite that can infect a variety of hosts, including pigs and humans, through water and food. Many studies on Cryptosporidium infection in pigs have been reported worldwide. However, the meta-analysis of Cryptosporidium infection in pigs in China has not been published. This study retrieved articles related to Cryptosporidium in pigs in China by using four databases: Chinese National Knowledge Infrastructure (CNKI), PubMed, VIP Chinese journal database and Wanfang Data. We retrieved 40 studies related to Cryptosporidium infection in China, and those articles were harvested from the inception to 1 January 2020. We estimated that the overall prevalence of pigs with Cryptosporidium in the selected period was 12.2% (4,349/30,404). In the sampling year subgroup, the prevalence rate after 2010 was the lowest at 8.7% (2,087/18,100). In Northern China, the Cryptosporidium prevalence was 47.9% (34/71). By contrast, the prevalence of Cryptosporidium in Southwestern China was only 6.9% (778/6,445). The infection rate of Cryptosporidium in diarrhoea pigs of 15.6% (74/384) was higher than that in non-diarrhoea pigs at 10.8% (378/2,840). Among the four age groups, the prevalence of weaning pigs of 16.2% (530/3,243) was the highest, and the difference was significant (p < .05). The prevalence of Cryptosporidium in extensive farming was 25.7% (660/3,121), which was significantly higher than in intensive farming 8.7% (566/6,336), and the prevalence of infection was related to the farming modes (p < .05). We also analysed the impact of different geographic factor subgroups (longitude, latitude, precipitation, temperature, humidity, climate and altitude) on the prevalence of pigs. The results showed that cryptosporidiosis was widespread in pigs in China. We suggest that appropriate control schemes should be developed according to the differences in breeding patterns and geographic conditions in different regions, and effective management measures should be developed to reduce the spread between pigs., (© 2020 Wiley-VCH GmbH.)

China has a long history of pig rearing, and it currently raises and consumes approximately half of the pigs in the world. Major improvements have been made in pig farming in China in the last four decades with the growing application of new livestock farming technologies. Among the new improvements, the use of antibiotics in pig farming is a common but not well-documented practise. In order to understand the behaviour of the farmers regarding antibiotic use in pig farming, we conducted a household survey in four townships of L County in Yunnan Province, China, during August 2014 and April 2015. In this survey, 404 farmer households were interviewed using a questionnaire. Among the farmers interviewed, 89% reported easy access to antibiotics, 83.7% reported experience of self-purchasing antibiotics, and 40.3% reported that they often used antibiotics in pig farming mainly for the prevention and treatment of pig diseases. These farmers identified 20 antibiotics that they had used in pig farming 6 months before the survey. Of these, 11 and 8 antibiotics have been categorised under 'critically important' and 'highly important' antimicrobial groups, respectively, by the World Health Organization (WHO), and 12 and 8 have been categorised under the 'Watch' and 'Access' groups, respectively, as per the 2019 WHO AWaRe classification of antibiotics. Factors associated with the behaviour of self-purchasing antibiotics included types of farms, sources of antibiotics, and previous experiences of pig diseases: those who were smallholders, buying antibiotics from veterinary drugstores and village vets, and whose pigs had suffered diseases previously were more likely to self-purchase antibiotics for their pigs. Farmers who cleaned their pigsties less frequently and those whose pigs had suffered from diseases used antibiotics more frequently as compared to their peer farmers., (© 2020 The Authors Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

Background: Pseudorabies (PR), caused by the pseudorabies virus (PRV), is an endemic disease in some regions of China. Although there are many reports on epidemiological investigations into pseudorabies, information on PRV gI antibody dynamics in one pig farm is sparse., Objectives: To diagnose PR and analyze the course of PR eradication in one pig farm., Methods: Ten brains and 1,513 serum samples from different groups of pigs in a pig farm were collected to detect PRV gE gene and PRV gI antibody presence using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively., Results: The July 2015 results indicated that almost all brain samples were PRV gE gene positive, but PRV gI antibody results in the serum samples of the same piglets were all negative. In the boar herd, from October 2015 to July 2018 three positive individuals were culled in October 2015, and the negative status of the remaining boars was maintained in the following tests. In the sow herd, the PRV gI antibody positive rate was always more than 70% from October 2015 to October 2017; however, it decreased to 27% in January 2018 but increased to 40% and 52% in April and July 2018, respectively. The PRV gI antibody positive rate in 100-day pigs markedly decreased in October 2016 and was maintained at less than 30% in the following tests. For 150-day pigs, the PRV gI antibody positive rate decreased notably to 10% in April 2017 and maintained a negative status from July 2017. The positive trend of PRV gI antibody with an increase in pig age remarkably decreased in three tests in 2018., Conclusions: The results indicate that serological testing is not sensitive in the early stage of a PRV infection and that gilt introduction is a risk factor for a PRV-negative pig farm. The data on PRV gI antibody dynamics can provide reference information for pig farms wanting to eradicate PR., Competing Interests: The authors declare no conflicts of interest., (© 2021 The Korean Society of Veterinary Science.)

Pseudorabies virus (PRV) is a major pathogen in pig husbandry and is also a risk to human well-being. Pigs with latent PRV infection carry the virus lifelong, and it can be activated under conducive conditions. This poses a very important challenge to the control of the virus and may even prevent its elimination. To investigate latent infection with wild-type (wt) PRV, and also infection due to the use of live attenuated vaccines on farms, 80 pigs from two large-scale swine operations were traced. At 6 months old, the quarantined pigs were slaughtered and brain samples were collected. A PCR assay targeting the gB and gE genes was developed to detect PRV DNA fragments in medulla oblongata. Five of the samples (6.3%) were gB and gE gene fragment double-positive, 60 of the samples (75%) were gB single-positive, and 15 samples (18.7%) showed double-negative. A portion of latency-associated transcripts (LATs), EP0 mRNA, were found to be present in the gB gene fragment positive samples. Furthermore, the five double-positive samples were transmitted blindly, and apparent cytopathic effects were found in three of the five samples in the fourth generation. By means of Western blotting, PCR and sequencing, two of the isolated viruses were found to be related to vaccine strain Bartha-K61. Another was closely related to domestic epidemic strains HN1201 and LA and relatively unrelated to other Asian isolates. These results suggest that the live vaccines are latently present in brains, in a manner similar to wt PRV, and this poses potential safety issues in the pig husbandry industry. Wt PRV and live vaccine viruses were found to co-exist in pigs, demonstrating that the live vaccines were unable to confer complete sterilizing immunity, which may explain outbreaks of pseudorabies on vaccinated farms., (© 2020 Blackwell Verlag GmbH.)

Cysticercosis caused by the metacestode larval stage of Taenia hydatigena formerly referred to as Cysticercus tenuicollis is a disease of veterinary importance that constitutes a significant threat to livestock production worldwide, especially in endemic regions due to condemnation of visceral organs and mortality rate of infected young animals. While the genetic diversity among parasites is found to be potentially useful in many areas of research including molecular diagnostics, epidemiology and control, that of T. hydatigena across the globe remains poorly understood. In this study, analysis of the mitochondrial DNA (mtDNA) of adult worms and larval stages of T. hydatigena isolated from dogs, sheep and a wild boar in China showed that the population structure consists of two major haplogroups with very high nucleotide substitutions involving synonymous and non-synonymous changes. Compared with other cestodes such as Echinococcus spp., the genetic variation observed between the haplogroups is sufficient for the assignment of major haplotype or genotype division as both groups showed a total of 166 point-mutation differences between the 12 mitochondrial protein-coding gene sequences. Preliminary analysis of a nuclear protein-coding gene (pepck) did not reveal any peculiar changes between both groups which suggests that these variants may only differ in their mitochondrial makeup.

Porcine circovirus 4 (PCV4), a new circovirus with a distinct relationship to other circoviruses, was identified in 2019 in several pigs with severe clinical disease in Hunan Province, China. To investigate the epidemic profile and genetic diversity of the virus, 63 clinical samples were collected from 24 different pig farms in 14 cities in Henan and Shanxi Provinces, China, between February 2018 and December 2019, and the partial Cap gene of PCV4 was amplified by PCR. Among the 63 samples, 16 (25.40%) were positive for PCV4, and 50% (12/24) of the pig farms were positive for PCV4. PCV4 was detected in samples from pigs with different clinical presentations. One PCV4 strain (Henan-LY1-2019) was sequenced in this study, and shared 98.4% genomic nucleotide identity with PCV4 strain HNU-AHG1-2019 (accession no. MK986820) detected on a pig farm in Hunan Province in 2019. A phylogenetic analysis based on the genomes of Henan-LY1-2019 and 31 reference strains showed that the Henan-LY1-2019 strain together with PCV4 strain HNU-AHG1-2019 was grouped in a relatively independent sub-branch, and separated from other viruses in the genus Circovirus. The results of this study extend our understanding of the molecular epidemiology of PCV4., (© 2020 Blackwell Verlag GmbH.)

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.)

Porcine deltacoronavirus (PDCoV) has been detected sporadically in China since its first description in 2012. In our study, 62 faecal and intestinal samples from pigs with diarrhoea were collected in Guangxi Province, China, during 2017 and 2018. Twelve samples (19.4%, 12/62) were positive for PDCoV. Five complete genomes of PDCoV were then determined, and sequence alignment revealed that the five strains had discontinuous deletions at 400-401 aa in non-structural protein 2 (NSP2) and 758-760 aa in non-structural protein 3 (NSP3) compared with the respective proteins in the HKU15-44 strain. Notably, the CHN-GX81-2018 strain contained two insertions in the S gene and 3'-UTR. Multiple sequence alignment and phylogenetic analysis showed that four strains shared 98.2%-98.4% nucleotide identity with CHN-AH-2004 and were classified into a new cluster of China lineage strains, whereas the CHN-GX81-2018 strain shared 98.7% nucleotide identity with Vietnam/Binh21/2015 and belonged to the Vietnam/Laos/Thailand lineage. Recombination analyses revealed that four strains were the result of recombination between CHN-HB-2014 and Vietnam/Binh21/2015 strains. This study demonstrated the co-existence of multiple lineages of PDCoV in China, and our findings will aid the reorganization and evolution of the virus., (© 2020 The Authors. Veterinary Medicine and Science Published by John Wiley & Sons Ltd.)

African Swine Fever (ASF) is a contagious disease of domestic and wild pigs caused by the African Swine Fever Virus (ASFV). The disease has spread globally in recent years with serious economic consequences to pork production. This report describes an ASF outbreak that occurred in a large-scale Chinese commercial pig farm. The outbreak started in 2018 and presents the spatial and temporal spread of infection in an intensive pig farm. Pig houses adjacent to exit rooms had a higher risk of infection (Odds ratio = 14.4, 95%CI: 1.5-140). Introduction of disease is presumed to have occurred through a contaminated vehicle used in the sale of pigs with poor productivity. This investigation shows the process of ASFV infection and spread in a facility with presumed adequate biosecurity measures. These findings may benefit others in the control of ASF in large-scale pig farms., (© 2020 Blackwell Verlag GmbH.)

The newly emerged lineage 1 porcine reproductive and respiratory syndrome viruses (PRRSVs) (especially the NADC30-like and NADC34-like viruses) have posed a direct threat to the Chinese pig industry since 2013. The phylogenetic, epidemic, and recombinant properties of these viruses have not yet systematically analysed in China. This report presents regular surveillance and field epidemiological studies for PRRSV across China from 2007 to 2019. From over 4,000 detected clinical samples, 70 open reading frame five sequences and four complete genomes of lineage 1 viruses were successfully obtained. Combined with global data, we conducted an extensive and systematic molecular phylogeny analysis using a maximum likelihood tree. The Chinese lineage 1 viruses were clustered, and their temporal and spatial distribution was further explored. Multiple viral introductions of lineage 1 virus from the United States to China were detected, and some became endemic in China. There are three sub-lineage 1 clusters: lineage 1.5 (NADC34-like), lineage 1.6 and New Intro cluster (NADC30-like). These viruses show high genetic diversity and a wide distribution in China, with Henan Province showing the highest diversity. Moreover, Chinese lineage 1 viruses have developed an endemic NADC30-like cluster. The demographic feature of this cluster showed a more or less constant population expansion history with a recent decreasing trend. Moreover, the genome recombination of Chinese lineage 1 with two dominant clusters (Chinese HP-PRRSVs: lineage 8.7 and VR2332-like: lineage 5.1) was frequently detected, both of which have commercial vaccine strains available. Furthermore, recombination hotspots were discovered near NSP9 and ORF2-4 regions of the genome. Overall, these findings provide important insights into the evolution and geographical diversity of Chinese lineage 1 PRRSV. These results will facilitate the development of programmes for the control and prevention of the emerging lineage 1 viruses in China., (© 2020 Blackwell Verlag GmbH.)

Forensic entomologists usually estimate the minimum postmortem interval (PMImin) using the time required for the oldest immature insects found on the corpse to grow to its development stage and age at the time of discovery. The sheep blow fly Lucilia sericata (Meigen, 1826) is a carrion fly found nearly worldwide, and important in forensics. We studied the development time of L. sericata from egg to adult at constant temperatures of 16, 19, 22, 25, 28, 31, and 34°C, and found that the times required are 913.2 ± 19.4, 588.8 ± 35.8, 459.8 ± 15.2, 373.2 ± 15.3, 308.0 ± 9.7, 272.5 ± 9.2, and 267.5 ± 10.5 h, respectively. We established three development models to infer the age of the immature insect: isomegalen diagram, isomorphen diagram, and thermal summation model. In addition, a regression analysis was performed on the relationship between body length and total development time from hatching to dispersing. The thermal summation constant during the development of L. sericata is 6023.2 degree hours and development threshold temperature is 9.19°C. The results of this experiment provide a basis for the use of L. sericata in the estimation of PMImin., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Haemophilus parasuis, a gram-negative bacterium as an early commensal colonizer in the upper respiratory tract of weaning pigs (Sus scrofa), is one of the most important bacterial pathogens affecting pig populations. It is the causative agent of Glässer's disease, causing systemic infection and polyserositis, meningitis, and arthritis. H. parasuis infection can result in high mortality and morbidity with, the significant economic losses for pig producers. To estimate the overall disease prevalence of H. parasuis in pigs from China, we performed a meta-analysis using five bibliographical databases: PubMed, ScienceDirect, CNKI, Wanfang, and VIP Chinese Journal Databases. A total of 41 articles published between 2005 and 2019, fulfilled the final inclusion criteria. The overall prevalence of H. parasuis in pigs in China was 27.8 % with the highest prevalence between 2011 and 2015 (41.0 %). In terms of pig age, the point estimate of H. parasuis prevalence was higher in suckling piglets (29.2 %) compared with that for other pig ages. The prevalence in the serum subgroup (29.8 %) was higher than that in the nasal swab subgroup (12.5 %). The results of the present meta-analysis showed that H. parasuis infection was common in pig populations in China; therefore, effective control measures are necessary to reduce this threat to pig populations., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The first recorded outbreak of African swine fever (ASF) was confirmed in the People's Republic of China in early August 2018. By the end of July 2019, there had been 150 outbreaks of ASF in 31 provinces, including 146 in domestic pigs and four in wild boar. The Chinese Government attaches great importance to the prevention and control of ASF. The Chinese animal health authority promptly launched the highest-priority emergency response against this key animal disease; initiated an extensive surveillance network covering all provinces; formulated and promulgated supporting policies, such as compensation for culled animals and financial credit for affected producers; and established a joint coordination body for ASF prevention and control, led by the Ministry of Agriculture and Rural Affairs and involving a further 20 Ministries, including the Departments of Transportation, Customs and Market Supervision. All levels of local government undertook territorial management responsibilities and developed support policies to encourage all stakeholders to take part in ASF prevention and control. Furthermore, the Chinese Government developed a strategy that integrated both the legal and scientific aspects of ASF control, formulating and releasing a comprehensive policy for the whole pork production chain 'from farm to fork'. The plan included daily disease reports from the disease monitoring network, and adopted effective measures, such as blockades and culling, restricting live pig movements and implementing controls on swill feeding, to cut off viral transmission routes to the greatest extent possible.