TYPE Editorial PUBLISHED 02 November 2022 DOI 10.3389/fvets.2022.1065549 Editorial: Emerging swine OPEN ACCESS viruses, Volume II EDITED AND REVIEWED BY Michael Kogut, Agricultural Research Service (USDA), Daniela S. Rajao1*, Carlos Juan Perfumo2 , United States Daniel Roberto Perez1 and Enric Mateu3 *CORRESPONDENCE Daniela S. Rajao 1 Department of Population Health, University of Georgia, Athens, GA, United States, 2 Faculty of daniela.rajao@uga.edu Veterinary Sciences, La Plata National University, La Plata, Argentina, 3 Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, Barcelona, Spain SPECIALTY SECTION This article was submitted to Veterinary Infectious Diseases, KEYWORDS a section of the journal Frontiers in Veterinary Science swine, virus, emerging, outbreaks, novel RECEIVED 09 October 2022 ACCEPTED 14 October 2022 PUBLISHED 02 November 2022 CITATION Rajao DS, Perfumo CJ, Perez DR and Editorial on the Research Topic Mateu E (2022) Editorial: Emerging Emerging swine viruses, Volume II swine viruses, Volume II. Front. Vet. Sci. 9:1065549. doi: 10.3389/fvets.2022.1065549 COPYRIGHT The continuous growth of the human population and the need for resources has © 2022 Rajao, Perfumo, Perez and Mateu. This is an open-access article led to expanding encroachment into wildlife habitats (1). Increased interaction among distributed under the terms of the humans, livestock, and wild animals can lead to spillover and spread of pathogens, Creative Commons Attribution License particularly viruses, from wildlife reservoir species. The past few years have shown (CC BY). The use, distribution or reproduction in other forums is the risk of these increased interactions to the global population. The spread of the permitted, provided the original novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted in a author(s) and the copyright owner(s) are credited and that the original global pandemic (COVID-19), leading to more than 600 million cases and 6 million publication in this journal is cited, in deaths worldwide, in addition to devastating social and economic consequences (2). accordance with accepted academic Coincidently, another pandemic caused by African swine fever virus (ASFV) arose in practice. No use, distribution or reproduction is permitted which does domestic pigs in China just prior to the COVID-19 pandemic, reaching many other Asian not comply with these terms. and European countries. It is estimated that the outbreak resulted in the loss of about 30% of the Chinese pig population, leading to devastating consequences to the overall global swine industry (3, 4). To meet the growing demand for meat and meat products, swine production has followed a similar growth trend (5). Following the COVID-19 pandemic, supply chain disruptions and increased meat prices are expected to reduce pork consumption and result in a slower growth than previous years. In countries with high swine production, production growth in the past 4 decades was accompanied by significant structural changes with a rapid shift to fewer and larger operations (5). These large production systems are characterized by tens of thousands susceptible animals concentrated in small areas. Current swine production systems involve continuous introduction and movement of pigs, often housing animals of different ages and immune status in the same facilities, providing the ideal environment for the introduction and spread of pathogens. Next generation genome sequencing techniques are becoming routinely used in virus diagnostics, contributing to a better understanding of virus evolution and virus discovery (6). Metagenomics and transcriptomics technologies allow for agnostic approaches that lead to detection and full genome characterization of potential pathogens in a sample, without the need to know about the organisms being investigated or to isolate and Frontiers in Veterinary Science 01 frontiersin.org Rajao et al. 10.3389/fvets.2022.1065549 grow viruses in a laboratory. These technologies contributed to Original research articles the discovery of novel organisms such as giant viruses present in environmental samples, characterization of human, animal, Nuanualsuwan et al. investigate the thermal inactivation and environmental viromes, in addition to the detection of novel of ASFV in three swill formulae with different nutritive emerging and reemerging viral pathogens (6, 7). compositions at the temperatures of 60, 70, 75, and 80◦ C. The Novel viruses of pigs have been detected in the last 3 authors also defined a prediction model to predict decimal to 4 decades at a higher speed than ever before. Among reduction time (DRT or DT ) for other inactivation temperatures. the viruses that resulted in the highest economic losses are The mean D60 , D70 , D75 , and D80 of ASFV in three swill re-emerging porcine reproductive and respiratory syndrome formulae were in the ranges 23.21–33.47, 5.83–10.91, 2.15– (PRRS), porcine circovirus type 2 (PCV2), influenza A viruses 2.22, and 1.36–1.47 min, respectively. Based on the results, (FLUAV), and porcine epidemic diarrhea virus (PEDv), which the estimated time for inactivation for the recommended are endemic in many high intensity swine production systems temperatures by the World Organization for Animal Health and continue to challenge producers and veterinarians (8– (WOAH; 90◦ C) and Food and Agriculture Organization (FAO; 11). Recent virus outbreaks such as those caused by ASFV 70◦ C) are 4 and 119 min, respectively. and classical swine fever virus (CSFV) have drastically Shi et al. characterized the ASFV strains circulating in impacted trade and the overall global swine market (4, 12). Guangxi province, southern China in the ongoing outbreak. Novel swine viruses such as PCV3, swine acute diarrhea For this study, 336 tissue samples collected from domestic pigs syndrome coronavirus (SADS-CoV), may lead to clinical that died with severe hemorrhagic disease in 86 farms during disease, while others such as porcine toroviruses (PToV), 2019–2020 were tested, and 66 ASFV strains were sequenced porcine bocavirus (PBoV), torque teno sus virus (TTSuV) are and genetically characterized. Phylogenetic analysis showed that mostly subclinical. However, the risk persists for these viruses genetically diverse strains circulated in the region in 2019–2020, to cause substantial disruptions to the swine industry. Some including strains of the genotypes I and II, as well as serogroups viruses detected in pigs may also pose a threat to public 4 and 8, the majority belonging to genotype II and serogroup health, such as Nipah virus and Hepatitis E virus (HEV) 8. Interestingly, both wildtype and gene-deleted ASFV strains (13, 14). were identified. This Research Topics comprises of six original research Shi et al. reported the development and testing of a new articles about characterization of ASFV and FLUAV, vaccines multiplex crystal digital PCR (dPCR) for differential detection of against pseudorabies virus (PRV), inactivation of ASFV, ASFV, CSFV, and PRRSV, a modified version of the conventional multiplex diagnostics of ASFV, CSFV, and PRRSV, and PCR. The assay targets detection of p72, 5′ untranslated region characterization of porcine parvovirus 7 (PPV7). Two brief (UTR), and ORF7 genes of each virus, respectively. The assay research reports are also included about PRV. showed high specificity and sensitivity, capable to detecting low levels of ASFV, CSFV, and PRRSV, but no non-specific detection of other swine viruses was observed. This assay proved to be Brief research reports accurate and a reliable tool for screening for ASFV, CSFV, and PRRSV infection, and could aid in the rapid detection Tan et al. reported a naturally occurring recombinant of outbreaks. event in Hunan province, China between PRV classical Ren et al. compares the efficacy of a commercially available strain and its derived HB-98 live attenuated vaccine strain, Bartha-K61 vaccine and an rPRV/XJ5-gI–/gE–/TK– prototype highlighting safer vaccines and/or vaccination protocols are vaccine against lethal challenge with a PRV variant strain. needed. The isolated HN-2019 the glycoprotein E (gE) Both vaccines were administered the same dose to 12 week- and gG genes of the PRV classical strain but the TK old pigs and resulted in protection, with all vaccinated pigs gene of the HB-98 vaccine strain. The recombinant strain surviving challenge. Pigs were equally protected against weight replicated to similar titers as the parental strains in vitro loss, pathology, and virus shedding. These results differe from but resulted in intermediary level of replication and disease previously published studies when younger pigs were used, in vivo. demonstrating the two vaccine can be effective in a less PRV Tan et al. investigated the seroprevalence of PRV in Hunan susceptible age. province in China during 2020 and 2021 and the awareness of Wen et al. reported the first detection of PPV7 in Inner the risks of this infectious agent among swine practitioners. In Mongolia Autonomous Region, China. More than 28% of the study, 18,812 pig serum samples and 1,634 tissue samples animals and 60% of herds were positive for PPV7, and were tested from 798 farms. The authors found that 8.9% co-infection with PCV2 and PCV3 was often observed. of animals and 20.2% of farms were seropositive for PRV-gE The authors sequenced and characterized four strains, antibodies, and 2.3% of tissues were positive for PRV nucleic demonstrating that all Mongolian PPV7 clustered together, acids, demonstrated PRV is prevalent in China. However, and showed multiple amino acid mutations compared to workers were mostly unaware of the risks of PRV to humans. reference strains. Frontiers in Veterinary Science 02 frontiersin.org Rajao et al. 10.3389/fvets.2022.1065549 Osorio-Zambrano et al. characterized the influenza A virus Conflict of interest circulating in swine in Colombia before, during, and after the 2009 H1N1 pandemic. Ten virus isolates were selected from a The authors declare that the research was conducted in repository, subtyped, and sequenced. Strains isolated in 2008, the absence of any commercial or financial relationships prior to the pandemic, carried an HA segment from the North that could be construed as a potential conflict American clade 1.A.1 classical lineage. After the introduction of of interest. the 2009 H1N1 virus, all isolates contained the HA and NA genes from pandemic clade 1A.3.3.2, demonstrating the pandemic lineage replaced the previously circulating classical H1N1 Publisher’s note lineage. Interestingly, evolution of the FLUAV gene segments within the studied strains followed a geographic pattern. All claims expressed in this article are solely those of the authors and do not necessarily represent those Author contributions of their affiliated organizations, or those of the publisher, the editors and the reviewers. 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