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Introduction: Oral fluid sampling and testing offers a convenient, unobtrusive mechanism for evaluating the health status of swine, especially grower and finisher swine. This assessment evaluates the potential testing of oral fluid samples with real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) to detect African swine fever, classical swine fever, or foot-and-mouth disease for surveillance during a disease outbreak and early detection in a disease-free setting., Methods: We used a series of logical arguments, informed assumptions, and a range of parameter values from literature and industry practices to examine the cost and value of information provided by oral fluid sampling and rRT-PCR testing for the swine foreign animal disease surveillance objectives outlined above., Results: Based on the evaluation, oral fluid testing demonstrated value for both settings evaluated. The greatest value was in an outbreak scenario, where using oral fluids would minimize disruption of animal and farm activities, reduce sample sizes by 23%-40%, and decrease resource requirements relative to current individual animal sampling plans. For an early detection system, sampling every 3 days met the designed prevalence detection threshold with 0.95 probability, but was quite costly., Limitations: Implementation of oral fluid testing for African swine fever, classical swine fever, or foot-and-mouth disease surveillance is not yet possible due to several limitations and information gaps. The gaps include validation of PCR diagnostic protocols and kits for African swine fever, classical swine fever, or foot-and-mouth disease on swine oral fluid samples; minimal information on test performance in a field setting; detection windows with low virulence strains of some foreign animal disease viruses; and the need for confirmatory testing protocol development., Competing Interests: The authors have declared that no competing interests exist.

African swine fever (ASF), classical swine fever (CSF) and foot-and-mouth disease (FMD) are considered to be three of the most detrimental animal diseases and are currently foreign to the U.S. Emerging and re-emerging pathogens can have tremendous impacts in terms of livestock morbidity and mortality events, production losses, forced trade restrictions, and costs associated with treatment and control. The United States is the world's top producer of beef for domestic and export use and the world's third-largest producer and consumer of pork and pork products; it has also recently been either the world's largest or second largest exporter of pork and pork products. Understanding the routes of introduction into the United States and the potential economic impact of each pathogen are crucial to (a) allocate resources to prevent routes of introduction that are believed to be more probable, (b) evaluate cost and efficacy of control methods and (c) ensure that protections are enacted to minimize impact to the most vulnerable industries. With two scoping literature reviews, pulled from global data, this study assesses the risk posed by each disease in the event of a viral introduction into the United States and illustrates what is known about the economic costs and losses associated with an outbreak., (© 2020 Wiley-VCH GmbH.)

On average 8,000 pork derived products are annually confiscated by Customs and Border Protection at the United States (US) ports of entry such as international airports, harbours or mail offices. These swine products with unknown sanitary status could pose a risk for foreign animal diseases introduction into the US. This study aimed at analysing the risk of African swine fever virus (ASFV) and classical swine fever virus (CSFV) being introduced into the US through prohibited swine products carried by air passengers (PSPAP) and identifying locations and time periods at higher risk where and when preventive and mitigation measures should be implemented. Our results estimated that the risk for CSFV entry was seven times higher and further spread between US airports than for ASFV. Specifically, the overall mean annual probability of ASFV entry was estimated as 0.061 at 95% confidence interval (CI) [0.007, 0.216] while the probability of CSFV entry was estimated as 0.414 (95% CI [0.074, 1]). For both diseases, July and May were the months at highest risk for entry. For ASFV, the origin countries of those PSPAP that represented the highest risk (above 70% of the total risk) were Ghana, Cape Verde, Ethiopia and the Russian Federation, while for CSFV above 90% of the risk at origin was concentrated in the Dominican Republic and Cuba, followed by India, Colombia, Peru, Ecuador and China. These results could be used to implement and feed real time surveillance systems, which could potentially help customs to increase the detection rate of smuggled products, indicating when and where to look for them. Similarly, these systems could be adapted and implemented to other diseases improving the cost-effectiveness of the resources invested in preventing entrance of diseases via air passengers' luggage., (© 2018 Blackwell Verlag GmbH.)

On 11 August 1999, an outbreak of classical swine fever (CSF) occurred in the municipality of San Carlos in the State of Tamaulipas, located on the United States-Mexico border. Sixty-eight dead and two sick pigs from a village were reported to the animal health authorities; tissue samples of sick pigs were confirmed as positive for CSF virus by indirect fluorescent antibody test. The population at risk consisted of 521 pigs, with crude mortality and attack rates of 13.05% and 0.38% respectively. However, on 24 August 1999, two more pigs were detected with clinical signs and their tissue samples confirmed as positive by indirect fluorescent antibody test and neutralizing peroxidase-linked assay, with a secondary attack rate of 0.38%. The outbreak was eradicated by implementing a slaughter policy, movement control, quarantine and surveillance, among other measures. After 6 months of quarantine, the disease was eradicated without resorting to vaccination. The possible sources of introduction of the CSF are also discussed.

Animal disease surveillance is an important component of the national veterinary infrastructure to protect animal agriculture and facilitates identification of foreign animal disease (FAD) introduction. Once introduced, pathogens shared among domestic and wild animals are especially challenging to manage due to the complex ecology of spillover and spillback. Thus, early identification of FAD in wildlife is critical to minimize outbreak severity and potential impacts on animal agriculture as well as potential impacts on wildlife and biodiversity. As a result, national surveillance and monitoring programs that include wildlife are becoming increasingly common. Designing surveillance systems in wildlife or, more importantly, at the interface of wildlife and domestic animals, is especially challenging because of the frequent lack of ecological and epidemiological data for wildlife species and technical challenges associated with a lack of non‐invasive methodologies. To meet the increasing need for targeted FAD surveillance and to address gaps in existing wildlife surveillance systems, we developed an adaptive risk‐based targeted surveillance approach that accounts for risks in source and recipient host populations. The approach is flexible, accounts for changing disease risks through time, can be scaled from local to national extents and permits the inclusion of quantitative data or when information is limited to expert opinion. We apply this adaptive risk‐based surveillance framework to prioritize areas for surveillance in wild pigs in the United States with the objective of early detection of three diseases: classical swine fever, African swine fever and foot‐and‐mouth disease. We discuss our surveillance framework, its application to wild pigs and discuss the utility of this framework for surveillance of other host species and diseases. [ABSTRACT FROM AUTHOR]

Because of the clinical and pathologic similarity to common endemic diseases, introduction of CSFV or ASFV strains of moderate to low virulence represents the greatest risk to North American swine herds. Producers, veterinarians, and diagnosticians should increase their awareness of these devastating diseases and request specific diagnostic testing whenever they are suspected. Production practices that improve biosecurity will reduce the risk of introduction of CSF and ASF and limit the spread if an incursion occurs. Additional resources. The following Web sites contain excellent color photographs that will assist producers and practitioners in identifying clinical signs and gross lesions associated with CSFV and ASFV: http://www.vet.uga.edu/vpp/gray_book/FAD and http://www.pighealth.com. The latter Web site and the OIE Web site (http://www.oie.int) offer updated information on current worldwide epizootics of ASF and CSF and other swine diseases. Details of biosecurity procedures can be found at http://www.agebb.missouri.edu; see publication G2340.

The article discusses a study which describes the development and evaluation of a real-time fluorogenic-probe hydrolysis (TaqMan) reverse transcription polymerase chain reaction (RT-PCR) for Classical swine fever (CSF). CSF is a swine disease that is economically devastating. The RT-PCR was developed by the U.S. Department of Agriculture at the Plum Island Animal Disease Center as an instrument to control CSF.

Iowa leads the United States in pork production, housing approximately one-third of the country's swine population. This puts Iowa at great economic risk if an outbreak of African swine fever, a disease that limits international trade opportunities, were to occur anywhere in the United States. To hone emergency response plans to combat an outbreak, the Iowa Department of Agriculture and Land Stewardship in September 2019 participated in a 4-day exercise with representatives from the other 13 top pork-producing states. This exercise involved a mock foreign animal disease response and helped to concisely summarize what pork producers could expect should a foreign animal disease be detected in Iowa.

African swine fever (ASF) causes significant morbidity and mortality in both domestic and wild suids (Sus scrofa), and disease outbreaks convey profound economic costs to impacted industries due to death loss, the cost of culling exposed/infected animals as the primary disease control measure, and trade restrictions. The co-occurrence of domestic and wild suids significantly complicates ASF management given the potential for wild populations to serve as persistent sources for spillover. We describe the unique threat of African swine fever virus (ASFV) introduction to the United States from epidemiological and ecological perspectives with a specific focus on disease management at the wild-domestic swine interface. The introduction of ASF into domestic herds would require a response focused on containment, culling, and contact tracing. However, detection of ASF among invasive wild pigs would require a far more complex and intensive response given the challenges of detection, containment, and ultimately elimination among wild populations. We describe the state of the science available to inform preparations for an ASF response among invasive wild pigs, describe knowledge gaps and the associated studies needed to fill those gaps, and call for an integrated approach for preparedness that incorporates the best available science and acknowledges sociological attributes and the policy context needed for an integrated disease response. [ABSTRACT FROM AUTHOR]

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: African swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains. Using an approximate Bayesian computation algorithm in conjunction with Monte Carlo simulation, we have estimated the adequate contact rate for moderately virulent ASFV strains and determined the statistical distributions for the durations of mild and severe clinical signs using individual, pig-level data. A discrete individual based disease transmission model was then used to estimate the time to detect ASF infection based on increased mild clinical signs, severe clinical signs, or daily mortality. Results: Our results indicate that it may take two weeks or longer to detect ASF in a finisher swine herd via mild clinical signs or increased mortality beyond levels expected in routine production. A key factor contributing to the extended time to detect ASF in a herd is the fairly long latently infected period for an individual pig (mean 4.5, 95% P.I., 2.4 - 7.2 days). Conclusion: These transmission model parameter estimates and estimated time to detection via clinical signs provide valuable information that can be used not only to support emergency preparedness but also to inform other simulation models of evaluating regional disease spread. [ABSTRACT FROM AUTHOR]

Background: Hydrocephalus is a neurological disease with an incidence of 80–125 per 100,000 births in the United States. Neuropathology comprises ventriculomegaly, periventricular white matter (PVWM) alterations, inflammation, and gliosis. We hypothesized that hydrocephalus in a pig model is associated with subventricular and PVWM cellular alterations and neuroinflammation that could mimic the neuropathology described in hydrocephalic infants. Methods: Hydrocephalus was induced by intracisternal kaolin injections in 35-day old female pigs (n = 7 for tissue analysis, n = 10 for CSF analysis). Age-matched sham controls received saline injections (n = 6). After 19–40 days, MRI scanning was performed to measure the ventricular volume. Stem cell proliferation was studied in the Subventricular Zone (SVZ), and cell death and oligodendrocytes were examined in the PVWM. The neuroinflammatory reaction was studied by quantifying astrocytes and microglial cells in the PVWM, and inflammatory cytokines in the CSF. Results: The expansion of the ventricles was especially pronounced in the body of the lateral ventricle, where ependymal disruption occurred. PVWM showed a 44% increase in cell death and a 67% reduction of oligodendrocytes. In the SVZ, the number of proliferative cells and oligodendrocyte decreased by 75% and 57% respectively. The decrease of the SVZ area correlated significantly with ventricular volume increase. Neuroinflammation occurred in the hydrocephalic pigs with a significant increase of astrocytes and microglia in the PVWM, and high levels of inflammatory interleukins IL-6 and IL-8 in the CSF. Conclusion: The induction of acquired hydrocephalus produced alterations in the PVWM, reduced cell proliferation in the SVZ, and neuroinflammation. [ABSTRACT FROM AUTHOR]

Influenza A viruses evolve rapidly to escape host immunity. In swine, this viral evolution has resulted in the emergence of multiple H1 and H3 influenza A virus (IAV) lineages in the United States (US) pig populations. The heterologous prime-boost vaccination strategy is a promising way to deal with diverse IAV infection in multiple animal models. However, whether or not this vaccination strategy is applicable to US swine to impart immunity against infection from North American strains of IAV is still unknown. We performed a vaccination-challenge study to evaluate the protective efficacy of using multivalent inactivated vaccine and/or a live attenuated IAV vaccine (LAIV) in pigs following multiple prime-boost vaccination protocols against a simultaneous H1N1 and H3N2 IAV infection. Our data show that pigs in the heterologous prime-boost vaccination group had more favorable outcomes consistent with a better response against virus challenge than non-vaccinated pigs. Additionally, delivering a multivalent heterologous inactivated vaccine boost to pigs following a single LAIV administration was also beneficial. We concluded the heterologous prime boost vaccination strategy may potentiate responses to suboptimal immunogens and holds the potential applicability to control IAV in the North American swine industry. However, more studies are needed to validate the application of this vaccination approach under field conditions. [ABSTRACT FROM AUTHOR]

Senecavirus A (SVA) belonging to the family Picornaviridae, genus Senecavirus was incidentally isolated in 2002 from the PER.C6 (transformed foetal retinoblast) cell line. However, currently, this virus is associated with vesicular disease in swine and it has been reported in countries such as the United States of America, Canada, China, Thailand and Colombia. In Brazil, the SVA was firstly reported in 2015 in outbreaks of vesicular disease in swine, clinically indistinguishable of Foot‐and‐mouth disease, a contagious viral disease that generates substantial economic losses. In the present work, it was standardized a diagnostic tool for SVA based on RNA reverse transcriptase droplet digital PCR (RT‐ddPCR) using one‐step and two‐step approaches. Analytical sensitivity and specificity were done in parallel with real‐time PCR, RT‐qPCR (one‐step and two‐step) for comparison of sensitivity and specificity of both methods. In the standardization of RT‐ddPCR, the double‐quenched probe and the temperature gradient were crucial to reduce background and improve amplitude between positive and negative droplets. The limit of detection and analytical specificity of techniques of one‐step techniques showed superior performance than two‐step methods described here. Additionally, the results showed 94.2% concordance (p < 0.001) for RT‐ddPCR and RT‐qPCR using the one‐step assay approach and biological samples from Brazilian outbreaks of Senecavirus A. However, ddRT‐PCR had a better performance than RT‐PCR when swine serum pools were tested. According to the results, the one‐step RT‐ddPCR and RT‐qPCR is highlighted to be used as an auxiliary diagnostic tool for Senecavirus A and for viral RNA absolute quantification in biological samples (RT‐ddPCR), being a useful tool for vesicular diseases control programs. [ABSTRACT FROM AUTHOR]

To help policy makers determine the need for current regulations (which require cooking of swill prior to feeding to swine), an assessment of the likelihood of exposing domestic swine in the continental United States of America (USA) to selected foreign animal disease agents by feeding uncooked swill was carried out. The hazard was assumed to originate from contraband food items entering the USA and subsequently being discarded in household waste. Such food waste may be collected by licensed waste feeders and fed to swine. This study showed that, of the four diseases studied, the probability of exposure was highest for the classical swine fever (hog cholera) virus. The median annual likelihood of one or more contaminated loads of swill being fed to swine in the continental USA was estimated as follows: classical swine fever virus: 0.063, foot and mouth disease virus: 0.043, swine vesicular disease virus: 0.005, African swine fever virus: 0.005.

Nineteen monoclonal antibodies (MAbs) with specificity for hog cholera virus (HCV) were prepared. They were used in an immune binding (peroxidase linked) assay to determine the reaction patterns of HCV isolates from Europe, Brazil, USA, Japan and Malaysia, as well as laboratory reference strains of the virus. A further panel of 17 MAbs raised against bovine virus diarrhoea virus (BVDV) was included in the study, together with 5 MAbs raised against a non-HCV pestivirus of porcine origin. All the MAbs were also tested against representative strains of BVDV and border disease virus. Six MAbs were HCV-specific, reacting with all isolates of HCV and none of the ruminant viruses. Among the other HCV MAbs geographical variation in reaction patterns was observed. There was evidence of antigenic distinction between recent European isolates, and archive material originally isolated more than 10 years ago.

Background The WHO estimates that there may be 50 million cases of dengue virus (DENV) infection worldwide every year. There is no safe vaccine against DENV licensed in the United States. The development of a balanced and effective anti-DENV vaccine is vital to preventing morbidity and mortality. Codagenix used its proprietary SAVE (Synthetic Attenuated Virus Engineering) platform to generate and test a live attenuated, tetravalent vaccine against DENV. Methods Codagenix used SAVE to substitute under-represented human codons and codon-pairs into the E protein sequences of contemporary strains of DENV1-4, producing either a fully human-cell-deoptimized prM-E (E-Min), or a partially deoptimized prM-E (E-W/Min) to allow for balancing of the vaccine's immunogenicity. Full genomes containing deoptimized E-Min and E-W/Min in the DENV2 backbone were transfected into cells to recover live-attenuated, human-cell-deoptimized vaccine strains. Mice were vaccinated with 106 FFU of each DENV vaccine (alone or together), boosted on day 21 and assessed for neutralizing antibodies by PRNT50 and survival after lethal challenge with mouse-adapted wild-type (WT) DENV. Cynomolgus macaques were immunized with a mixture of 106 FFU of each DENV vaccine strain. Two doses were administered on study day 1 and 57 and serum neutralizing antibodies were determined on day 57 and 85 by a microneutralization assay. Results SAVE deoptimized DENV viruses grew to wild-type (between 107 and 108 FFU/ml) levels at permissive temperatures (<37C). All vaccine strains generated neutralizing antibody levels comparable to WT. A tetravalent formulation containing all four E-Min strains protected mice from lethal challenge with DENV3. A tetravalent formulation of Codagenix DENV-E-W/Min vaccine elicited a robust and balanced neutralizing antibody response in non-human primates (NHPs) against all four DENV serotypes after a single dose. A second vaccine dose did not boost antibody titers significantly. Conclusion The ability to rationally balance the attenuation of multiple vaccine strains, thereby avoiding antibody-dependent enhancement, is a unique advantage of the Codagenix SAVE platform. Codagenix DENV vaccine viruses generated balanced, sterilizing immunity in NHPs after one dose. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Animal disease outbreaks, such as the recent outbreak of African Swine Fever in 2018, are a major concern for stakeholders across the food supply chain due to their potential to disrupt global food security, cause economic losses, and threaten animal welfare. As a result of their transboundary nature, discussions have shifted to preventive measures aimed at protecting livestock while ensuring food security and safety. Emergency assistance has been a critical response option during pandemics. However, this may not be sustainable in the long run because the expectation of government bailout may encourage risk taking behaviours. Our hypothesis is that an indemnity policy that is conditioned on showing biosecurity practices would increase compliance and reduce government expenditure during disease outbreaks. We developed and launched a survey from March to July 2022 targeted at swine producers across the US. From the survey, we examined livestock farmers' attitudes and intentions regarding biosecurity investment and assessed their attitudes towards the purchase of livestock insurance and reporting suspected infected livestock on their farm. We used a partial proportion odds model analysis to examine the model. Our analysis revealed that intention to call a veterinarian, trust in government agencies and risk perception of farmers were instrumental in the willingness to self-invest in biosecurity, purchase livestock insurance, and promptly report infected livestock on their farms. This provides evidence that biosecurity compliance would increase if indemnification was tied to a demonstration of effort to adopt biosecurity practices. We also show that individuals who have been in the industry for a longer period may become complacent and less likely to report outbreaks. Farmers with a higher share of income from their production operations bear a greater risk from their operational income and are more willing to report any suspected infections on their farms. The data suggest that motivating the willingness of farmers to invest in biosecurity while overcoming cost concerns is achievable. [ABSTRACT FROM AUTHOR]

Simple Summary: The spread of invasive wild pigs across the United States has been successfully slowed due to the establishment of a national management program. In this paper, we study the effectiveness of the national program by modeling the spread of wild pigs in the absence of intervention. Further, we use the models to assess the value of resources safeguarded from the threat of wild pigs. Our findings indicate that, on average, invasive wild pigs were prevented from spreading to 724 counties, and USD 40.2 billion in resource value was safeguarded over the first eight years of the program. Continuation of the program will deliver additional benefits and further research is critical to understand its comprehensive economic effects. Wild pigs (Sus scrofa) are one of the most destructive invasive species in the US, known for causing extensive damage to agricultural commodities, natural resources, and property, and for transmitting diseases to livestock. Following the establishment of the National Feral Swine Damage Management Program (NFSDMP) in 2014, the expansion of wild pig populations has been successfully slowed. This paper combines two modeling approaches across eight separate models to characterize the expansion of wild pig populations in the absence of intervention by the NFSDMP and forecasts the value of a subset of resources safeguarded from the threat of wild pigs. The results indicate that if wild pigs had continued spreading at pre-program levels, they would have spread extensively across the US, with significant geographic variation across modeling scenarios. Further, by averting the threat of wild pigs, a substantial amount of crops, land, property, and livestock was safeguarded by the NFSDMP. Cumulatively, between 2014 and 2021, wild pig populations were prevented from spreading to an average of 724 counties and an average of USD 40.2 billion in field crops, pasture, grasses, and hay was safeguarded. The results demonstrate that intervention by the NFSDMP has delivered significant ecological and economic benefits that were not previously known. [ABSTRACT FROM AUTHOR]

The rapid expansion of wild pigs (Sus scrofa) throughout the United States has been fueled by unlawful introductions, with invasive populations causing extensive crop losses, damaging native ecosystems, and serving as a reservoir for disease. Multiple states have passed laws prohibiting the possession or transport of wild pigs. However, genetic and phenotypic similarities between domestic pigs and invasive wild pigs—which overwhelmingly represent domestic pig and wild boar hybrids—pose a challenge for the enforcement of such regulations. We sought to exploit wild boar ancestry as a common attribute among the vast majority of invasive wild pigs as a means of genetically differentiating wild pigs from breeds of domestic pig found within the United States. We organized reference high‐density single nucleotide polymorphism genotypes (1039 samples from 33 domestic breeds and 382 samples from 16 wild boar populations) into five genetically cohesive reference groups: mixed‐commercial breeds, Durocs, heritage breeds, primitive breeds, and wild boar. Building upon well‐established genetic clustering approaches, we structured the test statistic to describe the difference in the likelihood of a given genotype's ancestry vectors (sensu genetic clustering analysis) if derived strictly from the four described domestic pig reference groups versus allowing for admixture from the wild boar group. By fitting statistical distributions to test statistics of reference domestic pigs, we characterized the distribution of the null hypothesis that a given genotype descends strictly from domestic pig reference groups. We tested the approach with simulated genotypes and empirical data from an additional 29 breeds of domestic pig represented by 435 unique genotypes; all associated test statistics for simulated and empirical domestic pig challenge sets fell within the distribution of reference domestic pigs. We then evaluated 6566 invasive wild pigs sampled across the contiguous United States, of which 63% exceeded the maximum threshold for domestic pigs and could be statistically classified as possessing wild boar ancestry. This approach provides a scientific foundation to enforce regulations prohibiting the possession of this destructive invasive species. Further, this computationally efficient and generalizable approach could be readily adapted to quantify gene flow among ecological systems of conservation or management concern. [ABSTRACT FROM AUTHOR]

Background: Japanese encephalitis virus (JEV) is a mosquito-borne zoonotic flavivirus and the leading cause of pediatric encephalitis in the Asian Pacific region. The transmission cycle primarily involves Culex spp. mosquitoes and Ardeid birds, with domestic pigs (Sus scrofa domestica) being the source of infectious viruses for the spillover of JEV from the natural endemic transmission cycle into the human population. Although many studies have concluded that domestic pigs play an important role in the transmission cycle of JEV, and infection of humans, the role of feral pigs in the transmission of JEV remains unclear. Since domestic and feral pigs are the same species, and because feral pig populations in the United States are increasing and expanding geographically, the current study aimed to test the hypothesis that if JEV were introduced into the United States, feral pigs might play a role in the transmission cycle. Materials and Methods: Sinclair miniature pigs, that exhibit the feral phenotype, were intradermally inoculated with JEV genotype Ib. These pigs were derived from crossing miniature domestic pig with four strains of feral pigs and were used since obtaining feral swine was not possible. Results: The Sinclair miniature pigs became viremic and displayed pathological outcomes similar to those observed in domestic swine. Conclusion: Based on these findings, we conclude that in the event of JEV being introduced into the United States, feral pig populations could contribute to establishment and maintenance of a transmission cycle of JEV and could lead to the virus becoming endemic in the United States. [ABSTRACT FROM AUTHOR]

Simple Summary: As African swine fever approaches the United States, it is important that the swine industry has safeguards in place to prevent catastrophic disruptions in the event of an outbreak. This review outlines current knowledge of African swine fever, disease management strategies, and the risks presented by the unique exhibition swine sector. African swine fever is a high-consequence foreign animal disease endemic to sub-Saharan Africa and the island of Sardinia. The U.S. is the world's third largest pork producer, and ASF introduction would severely disrupt the pork supply chain, emphasizing the need to protect market access for U.S. proteins. However, niche producers raising swine intended for exhibition may not follow stringent biosecurity protocols, and livestock show circuits may promote untracked animal movement across the country, potentially exacerbating virus' spread in the event of ASF incursion into the U.S. Youth membership in state or national swine organizations offers a route for outreach and educational activities to enhance foreign animal disease preparedness, and adult presence at swine exhibitions allows a wide variety of programming for all ages to better serve all levels of understanding. [ABSTRACT FROM AUTHOR]

African swine fever ( ASF) is a highly contagious haemorrhagic disease of pigs that has the potential to cause mortality nearing 100% in naïve animals. While an outbreak of ASF in the United States' pig population (domestic and feral) has never been reported, an introduction of the disease has the potential to cause devastation to the pork industry and food security. During the recovery phase of an outbreak, an antibody detection diagnostic assay would be required to prove freedom of disease within the previously infected zone and eventually nationwide. Animals surviving an ASF infection would be considered carriers and could be identified through the persistence of ASF viral antibodies. These antibodies would demonstrate exposure to the disease and not vaccination, as there is no ASF vaccine available. A well-established commercial enzyme-linked immunosorbent assay ( ELISA) detects antibodies against ASF virus ( ASFV), but the diagnostic specificity of the assay had not been determined using serum samples from the pig population of the United States. This study describes an evaluation of the World Organization for Animal Health ( OIE)-recommended Ingezim PPA COMPAC ELISA using a comprehensive cohort ( n = 1791) of samples collected in the United States. The diagnostic specificity of the assay was determined to be 99.4% (95% confidence interval ( CI): [98.9, 99.7]). The result of this study fills a gap in understanding the performance of the Ingezim PPA COMPAC ELISA in the ASF naïve pig population of the United States. [ABSTRACT FROM AUTHOR]

Simple Summary: In response to disease outbreaks or other urgent circumstances, an increasing number of farm animals in the United States (US) are being killed en masse by depopulation. In the past few years, depopulation methods that rely on heatstroke as the mechanism of killing have been used with increasing frequency to kill birds and pigs raised for food production. While they are defended as expedient and faster to implement, heatstroke-based methods severely compromise animal welfare and there is a prolonged period prior to the animals losing consciousness. The US veterinary profession is entrusted with an ethical responsibility to protect and advance animal welfare, yet its classification of the heatstroke-based depopulation method Ventilation Shutdown Plus is used to justify this method's widespread use. Numerous strategies are suggested for how the US veterinary profession, including the American Veterinary Medical Association, can encourage the use of more humane methods when depopulations are performed. Depopulation of food-producing animals is becoming increasingly common in response to both disease outbreaks and supply chain disruptions. In 2019, the American Veterinary Medical Association released depopulation guidelines classifying certain heatstroke-based killing methods as "permitted in constrained circumstances", when circumstances of the emergency constrain reasonable implementation of "preferred" methods. Since then, tens of millions of birds and pigs have been killed by such methods, termed ventilation shutdown (VSD) Plus Heat and VSD Plus High Temperature and Humidity. While no research using validated measures of animal welfare assessment has been performed on these methods, their pathophysiology suggests that animals are likely to experience pain, anxiety, nausea, and heat distress prior to loss of consciousness. Heatstroke-based methods may result in prolonged suffering and often do not achieve 100% mortality. Potential and available alternative depopulation methods are briefly reviewed. The veterinary profession's ethical obligation to protect animal welfare in the context of depopulations is discussed. [ABSTRACT FROM AUTHOR]

African swine fever virus (ASFv) is a virulent pathogen that threatens domestic swine industries globally and persists in wild boar populations in some countries. Persistence in wild boar can challenge elimination and prevent disease‐free status, making it necessary to address wild swine in proactive response plans. In the United States, invasive wild pigs are abundant and found across a wide range of ecological conditions that could drive different epidemiological dynamics among populations. Information on the size of the control areas required to rapidly eliminate the ASFv in wild pigs and how this area should change with management constraints and local ecology is needed to optimize response planning. We developed a spatially explicit disease transmission model contrasting wild pig movement and contact ecology in two ecosystems in Southeastern United States. We simulated ASFv spread and determined the optimal response area (reported as the radius of a circle) for eliminating ASFv rapidly over a range of detection times (when ASFv was detected relative to the true date of introduction), culling capacities (proportion of wild pigs in the culling zone removed weekly) and wild pig densities. Large radii for response areas (14 km) were needed under most conditions but could be shortened with early detection (≤ 8 weeks) and high culling capacities (≥ 15% weekly). Under most conditions, the ASFv was eliminated in less than 22 weeks using optimal control radii, although ecological conditions with high rates of wild pig movement required higher culling capacities (≥ 10% weekly) for elimination within 1 year. The results highlight the importance of adjusting response plans based on local ecology and show that wild pig movement is a better predictor of the optimal response area than the number of ASFv cases early in the outbreak trajectory. Our framework provides a tool for determining optimal control plans in different areas, guiding expectations of response impacts, and planning resources needed for rapid elimination. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is a contagious disease with high mortality in domestic and feral swine populations. Although it is not a zoonosis, its spread may have severe socio‐economic and public health consequences. The activities of veterinary services are essential for controlling ASF outbreaks within a country, but also for diminishing its threat of spread to neighbouring countries, and for recognizing its entry into countries that are currently free. ASF requires quick responses and permanent monitoring to identify outbreaks and prevent spread, and both aspects can be heavily undercut during the COVID‐19 pandemic. This paper analyses changing patterns of the main drivers and pathways for the potential introduction of ASFV into the United States during the COVID‐19 pandemic, including international movements of people, swine products and by‐products. Data on commercial flights and merchant ships was used as a proxy to indirectly assess the flow of illegal products coming from ASF affected countries. Results from this study highlight a decreasing trend in the legal imports of swine products and by‐products from ASF affected countries (Sen's slope = −99, 95% CI: −215.34 to −21.26, p‐value < 0.05), while no trend was detected for confiscations of illegal products at ports of entry. Additionally, increasing trends were detected for the monthly number of merchant ships coming from ASF affected countries (Sen's slope = 0.46, 95%CI 0.25–0.59), the monthly value of imported goods ($) through merchant ships (Sen's slope = 1513196160, 95%CI 1072731702–1908231855), and the monthly percentage of commercial flights (Sen's slope = 0.005, 95%CI 0.003–0.007), with the majority of them originating from China. Overall, the findings show an increased connection of the United States with ASF affected countries, highlighting the risk posed by ASF during a global public health crisis. [ABSTRACT FROM AUTHOR]

Objective—To estimate the annual cost of infections attributable to porcine reproductive and respiratory syndrome (PRRS) virus to US swine producers. Design—Economic analysis. Sample Population—Data on the health and productivity of PRRS-affected and PRRS-unaffected breeding herds and growing-pig populations were collected from a convenience sample of swine farms in the midwestern United States. Procedure—Health and productivity variables of PRRS-affected and PRRS-unaffected swine farms were analyzed to estimate the impact of PRRS on specific farms. National estimates of PRRS incidence were then used to determine the annual economic impact of PRRS on US swine producers. Results—PRRS affected breeding herds and growing pig populations as measured by a decrease in reproductive health, an increase in deaths, and reductions in the rate and efficiency of growth. Total annual economic impact of these effects on US swine producers was estimated at $66.75 million in breeding herds and $493.57 million in growing-pig populations. Conclusions and Clinical Relevance—PRRS imposes a substantial financial burden on US swine producers and causes approximately $560.32 million in losses each year. By comparison, prior to eradication, annual losses attributable to classical swine fever (hog cholera) and pseudorabies were estimated at $364.09 million and $36.27 million, respectively (adjusted on the basis of year 2004 dollars). Current PRRS control strategies are not predictably successful; thus, PRRS-associated losses will continue into the future. Research to improve our understanding of ecologic and epidemiologic characteristics of the PRRS virus and technologic advances (vaccines and diagnostic tests) to prevent clinical effects are warranted. [ABSTRACT FROM AUTHOR]

Soy‐based products are known to pose a viable risk to U.S. swine herds because of their ability to harbour and transmit virus. This publication aimed to evaluate soy imports into the United States as a whole and from foreign animal disease positive (FAD‐positive) countries to determine which products are being imported in the highest quantities and observe potential trends in imports from FAD‐positive countries. Import data were accessed through the United States International Trade Commission website (USITC DataWeb) and summarized using R (version 4.0.2, R core team, Vienna, Austria). Twenty‐one different Harmonized Tariff Schedule (HTS) codes were queried to determine quantities (metric tonnes, MT) and breakdown of different soy product types being imported into the United States from 2015 to 2020. A total of 78 different countries exported soy products to the United States in 2019 and 2020 with top contributors being Canada (546,467 and 481,497 MT, respectively), India (397,858 and 430,621 MT, respectively) and Argentina (122,116 and 79,471 MT, respectively). Soy oilcake (582,273 MT) was imported in the largest quantities, followed by organic soybeans (270,194 MT) and soy oil (134,436 MT) for 2020. Of the 78 countries, 46 had cases of FAD reported through the World Organization for Animal Health (OIE) World Animal Health Information Database (WAHIS). Top exporters of soy products to the United States from FAD‐positive countries in 2019 and 2020 were India (397,858 and 430,621 MT, respectively), Argentina (122,116 MT in 2019) and Ukraine (40,293 and 56,392 MT, respectively). The risk of FAD introduction to the United States through soy imports can fluctuate based on where FAD outbreaks are occurring, shipping methods and end usage of products. A system to monitor these factors could help make future decisions about trade and risk of FAD introduction to U.S. swine herds. [ABSTRACT FROM AUTHOR]

Porcine circovirus 3 (PCV3) was first discovered in 2016, almost concomitantly by two groups of researchers in the United States. The novel case was reported in a group of sows with chronic reproductive problems with clinical presentation alike porcine dermatitis and nephropathy syndrome (PDNS), where metagenomic sequencing revealed a genetically divergent porcine circovirus designated PCV3. The discovery of PCV3 in a PDNS case, which used to be considered as part of PCVAD attributed to PCV2 (porcine circovirus 2), has garnered attention and effort in further research of the novel virus. Just when an infectious molecular DNA clone of PCV3 has been developed and successfully used in an in vivo pathogenicity study, yet another novel PCV strain surfaced, designated PCV4 (porcine circovirus 4). So far, PCV3 has been reported in domestic swine population globally at low to moderate prevalence, from almost all sample types including organ tissues, faecal, semen and colostrum samples. PCV3 has been associated with a myriad of clinical presentations, from PDNS to porcine respiratory disease complex (PRDC). This review paper summarizes the studies on PCV3 to date, with focus on diagnosis. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV) remains widespread in the North American pig population. Despite improvements in virus characterization, it is unclear whether PRRSV infections are a product of viral circulation within production systems (local) or across production systems (external). Here, we examined the local and external dissemination dynamics of PRRSV and the processes facilitating its spread in three production systems. Overall, PRRSV genetic diversity has declined since 2018, while phylodynamic results support frequent external transmission. We found that PRRSV dissemination predominantly occurred mostly through transmission between farms of different production companies for several months, especially from November until May, a timeframe already established as PRRSV season. Although local PRRSV dissemination occurred mainly through regular pig flow (from sow to nursery and then to finisher farms), an important flux of PRRSV dissemination also occurred in the opposite direction, from finisher to sow and nursery farms, highlighting the importance of downstream farms as sources of the virus. Our results also showed that farms with pig densities of 500 to 1,000 pig/km2 and farms located at a range within 0.5 km and 0.7 km from major roads were more likely to be infected by PRRSV, whereas farms at an elevation of 41 to 61 meters and surrounded by denser vegetation were less likely to be infected, indicating their role as dissemination barriers. In conclusion, our results demonstrate that external dissemination was intense, and reinforce the importance of farm proximity on PRRSV spread. Thus, consideration of farm location, geographic characteristics and animal densities across production systems may help to forecast PRRSV collateral dissemination. [ABSTRACT FROM AUTHOR]