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Classical swine fever (CSF), sometimes referred to as hog cholera, is a highly contagious, virally based, systemic illness that affects both domestic and wild pigs. The virus known as classical swine fever virus (CSFV) is a member of the Flaviviridae family, specifically the genus Pestivirus. This disease is thought to be endemic in many Asian countries that produce pork as well as in several countries in Central and South America, the Caribbean, and elsewhere. As previously indicated, depending on the virulence of the virus strain involved and several host circumstances, clinical indications of CSFV infection can vary greatly, ranging from abrupt fatality to an occult course. CSF diagnosis can be made by serological detection, antigen, RNA, and isolation. CSF's highly varied symptoms and post-mortem pathology resemble those of African swine fever (ASF). ASF, the kind of CSFV, the pig's age, and its susceptibility all affect the clinical symptoms. Pigs that contract CSFV, a highly infectious and economically significant virus. The great economic significance of the swine business makes the CSFV a potential bioterrorism threat. Live attenuated CSF vaccinations have been around for many years and are quite safe and effective. Controlling epidemics in CSFV-free zones requires quick action. Pigs that are impacted must be slaughtered, and the carcasses must be buried or burned., Competing Interests: The authors declare that there is no conflict of interest.

Previous studies have emphasized the necessity of surveillance and control measures for hepatitis E virus (HEV) infection in wild boars, an important reservoir of HEV. To assess the current situation of HEV infection in wild boars in Japan, this study investigated the prevalence and genetic diversity of HEV among wild boars captured in 16 prefectures of Japan during 2018-2023. Serum samples from 968 wild boars were examined for anti-HEV IgG antibodies and HEV RNA. The prevalence of anti-HEV IgG varied geographically from 0 % to 35.0 %. HEV RNA was detected in 3.6 % of boars, with prevalence varying by prefecture from 0 % to 22.2 %. Genotype 3 was the most prevalent genotype (91.9 %), followed by genotype 4 (5.4 %), with one strain closely related to genotype 6. The prevalence of HEV infection among wild boars decreased from 2018/2019 to 2022/2023 with significant declines in levels of anti-HEV IgG antibodies (14.5 % vs. 6.2 %, P < 0.0001) and HEV RNA (7.6 % vs. 1.5 %, P < 0.0001). Regional analysis showed varying trends, with no HEV RNA-positive boars found in several regions in recent years. A plausible factor contributing to the decline in HEV infection is the application of countermeasures, including installing fences to prevent intrusion into pig farms, implemented in response to the emergence of classical swine fever virus (CSFV) infection in wild boars and domestic pigs, with incidents reported annually since 2018. Further investigation is warranted to explore the association between countermeasures to CSFV infection and the decrease in HEV infection among wild boars., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Classical swine fever has been spreading across the country since its re-emergence in Japan in 2018. Gifu Prefecture has been working diligently to control the disease through the oral vaccine dissemination targeting wild boars. Although vaccines were sprayed at 14,000 locations between 2019 and 2020, vaccine ingestion by wild boars was only confirmed at 30% of the locations. Here, we predicted the vaccine ingestion rate at each point by Random Forest modeling based on vaccine dissemination data and created prediction surfaces for the probability of vaccine ingestion by wild boar using spatial interpolation techniques. Consequently, the distance from the vaccination point to the water source was the most important variable, followed by elevation, season, road density, and slope. The area under the curve, model accuracy, sensitivity, and specificity for model evaluation were 0.760, 0.678, 0.661, and 0.685, respectively. Areas with high probability of wild boar vaccination were predicted in northern, eastern, and western part of Gifu. Leave-One-Out Cross Validation results showed that Kriging approach was more accurate than the Inverse distance weighting method. We emphasize that effective vaccination strategies based on epidemiological data are essential for disease control and that our proposed tool is also applicable for other wildlife diseases., (© 2024. The Author(s).)

Classical swine fever (CSF) re-emerged in Gifu Prefecture, central Japan, in September 2018 and is currently widespread in wild boar populations. Due to its widespread in wild boars, an oral mass vaccination strategy was initiated in March 2019, employing a commercial bait vaccine that is a live attenuated vaccine. To enhance the effectiveness of oral vaccination, it is crucial to determine the vaccine's effective spatial range. This understanding is essential for devising a comprehensive vaccination strategy, which should also include a preliminary investigation of wild boar habitats before vaccination. This study aimed to estimate the effective range of oral vaccination for wild boars against CSF by analyzing the geographical relationship between immune wild boars and vaccination points within the vaccination areas in Gifu Prefecture. This study utilized oral vaccination data from April 2021 to March 2022. The prevalence of CSF infections in wild boars remained below 5% in this period, suggesting limited disease transmission and immune wild boars were considered to be induced by the effect of vaccination. Two vaccination campaigns were conducted during this period, with almost 2000 vaccination points each. To investigate the factors associated with the intensity (i.e., density) of immune wild boar, the nearest distances to a vaccination point and to a susceptible wild boar were evaluated as explanatory variables. The Rhohat procedure and point process model were utilized to analyze the relationship between the intensity of immune wild boars and the explanatory variables. The point process model revealed a significant decrease in the intensity of immune wild boars when the distance from the nearest vaccination point exceeded 500 m, indicating that the effective spatial range of bait vaccination is within 500 m of the vaccination point. Although the distance to the nearest susceptible animal did not show significance in the model, Rhohat plots indicated that the intensity of immune wild boars decreased at distances greater than 1200 m from the nearest susceptible wild boar. This finding highlights the importance of investigating susceptible wild boar populations within a range of at least 1200 m from a vaccination point before implementation. The present study revealed the effective range of oral vaccination for wild boars against CSF and indicated the importance of investigating susceptible wild boar habitats around vaccination points before the implementation of vaccination. These findings may help improve the effectiveness of oral vaccinations., Competing Interests: Declaration of Competing Interest There are no conflicts of interest to declare., (Copyright © 2023 Elsevier B.V. All rights reserved.)

African swine fever (ASF) and classical swine fever (CSF) are transboundary animal diseases (TADs) of pigs. Much effort and resources are regularly put into preventing these diseases' introduction in free areas. Passive surveillance activities bring the highest chances for the early detection of TAD incursions because they are routinely and widely conducted at farms, and because these activities focus on the time between introduction and when the first sample is sent for diagnostic testing. The authors proposed the implementation of an enhanced passive surveillance (EPS) protocol based on collecting data through participatory surveillance actions using an objective and adaptable scoring system to aid the early detection of ASF or CSF at the farm level. The protocol was applied in two commercial pig farms for ten weeks in the Dominican Republic, which is a CSF- and ASF-infected country. This study was a proof of concept, based on the EPS protocol to aid detection of substantial variations in the risk score triggering testing. One of the followed farms had score variation, which triggered testing of the animals, although the test results were negative. The study enables assessment of some of the weaknesses associated with passive surveillance and provides lessons applicable to the problem. Results demonstrate the potential for overcoming some issues preventing the broad application of EPS protocols and suggest that standardised approaches may contribute to the early detection of CSF and ASF introductions.

The classical swine fever virus (CSFV) is a species member of the family Flaviviridae. CSFV is widely distributed in the world causing a severe impact on pig industry. This pathogen is considered restricted to domestic and wild suids. However, some reports from 2014 to 2018 showed the presence of the CFSV antigen in the bovine species. The virus was found in commercialized batches of fetal bovine serum (FBS) of Chinese origin and in bovine herds in in the provinces of Henan and Jiangsu, China, and in Tamil Nadu and Meghalaya, southern and north‑eastern states of India, respectively. Detection was done using antigen capture ELISA and RT‑PCR tests. In certain cases, animals with natural infection showed clinical signs and reproduction was also affected. Genetic characterization was performed considering the 5'‑UTR sequences of the bovine strains. In addition, the entire CSFV E2 genomic region could be amplified from two positive animals. The bovine strains were genetically related to the Chinese CSFV live attenuated hog cholera lapinized vaccine (HCLV) strain used in pigs, sharing sequence characteristics. The vaccine strain HCLV was widely used in China to protect bovines and yaks from bovine viral diarrhea, and, as a possible consequence, inducing an adaptation in cattle and a further natural diffusion. Furthermore, a contaminant strain from China was genetically distant from all other previously described genotypes of the CSFV. This suggests also the occurrence of micro evolutive step in the species related to geographical segregation. These observations deserve attention and further investigations, especially relevant in countries where CSFV control and eradication strategies are applied.

Classical swine fever (CSF) is one of the most important re-emergent swine diseases worldwide. Despite concerted control efforts in the Andean countries, the disease remains endemic in several areas, limiting production and trade opportunities. In this study, we aimed to determine the risk factors and spatiotemporal implications associated with CSF in Ecuador. We analysed passive surveillance and vaccination campaign datasets from 2014 to 2020; Then, we structured a herd-level case-control study using a logistic and spatiotemporal Bayesian model. The results showed that the risk factors that increased the odds of CSF occurrence were the following: swill feeding (OR 8.53), time until notification (OR 2.44), introduction of new pigs during last month (OR 2.01) and lack of vaccination against CSF (OR 1.82). The spatiotemporal model showed that vaccination reduces the risk by 33%. According to the priority index, the intervention should focus on Morona Santiago and Los Rios provinces. In conclusion, the results highlight the complexity of the CSF control programs, the importance to improve the overall surveillance system and the need to inform decision-makers and stakeholders.

Background: Reemergent local outbreaks of classical swine fever (CSF) occurred simultaneously in multiple pig farms on CSF-free Jeju Island, South Korea, in 2014 because of inadvertent injection of a commercial CSF (LOM) vaccine into pregnant sows. The LOM virus has since spread across the island and has become endemic in Jeju herds, raising concern about possible reversion to the virulence of the LOM vaccine. We previously isolated LOM-derived field CSF virus (CSFV) strains with unique insertion-deletion (INDEL) mutations in the 3'-untranslated region (UTR), designated LOM-derived Jeju 3'-UTR INDEL variants, from CSF-recurrent swine farms on Jeju Island in 2019., Methods: The present study conducted animal experiments to investigate whether a 2019 emergent LOM 3'-UTR INDEL variant, KNU-1905, has reverted to a pathogenic form in conventional pigs (n = 10)., Results: Experimental animal infection showed that pigs inoculated with the commercial LOM vaccine strain developed no adverse effects compared to the sham-infected pigs. However, KNU-1905 displayed pathogenic characteristics in pigs, including clinical symptoms (e.g., lethargy, conjunctivitis, nasal discharge, and diarrhoea), weight loss, and gross lesions. Moreover, viremia, virus shedding in faeces and nasal fluids, and viral loads in various tissues of all the KNU-1905-infected pigs were highly significant, in contrast to those of the LOM-infected group in which CSFV RNA was detected only in the serum, nasal, and tonsil samples of one identical pig., Conclusions: Overall, the LOM-derived field isolate with molecular variations induced clinical adverse events in pigs, which commonly shed considerable amounts of CSFV. This study provides evidence that the genetic evolution of the LOM-derived CSFV circulating on Jeju Island might have allowed the LOM vaccine to recover its primary prototype and that these variants might have induced chronic or persistent infection in pigs that can shed CSFV in field farms leading to a risk of transmission among pigs or farms in this former CSF-free region., (© 2022 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Understanding the impact of vaccination in a host population is essential to control infectious diseases. However, the impact of bait vaccination against wildlife diseases is difficult to evaluate. The vaccination history of host animals is generally not observable in wildlife, and it is difficult to distinguish immunity by vaccination from that caused by disease infection. For these reasons, the impact of bait vaccination against classical swine fever (CSF) in wild boar inhabiting Japan has not been evaluated accurately. In this study, we aimed to estimate the impact of the bait vaccination campaign by modelling the dynamics of CSF and the vaccination process among a Japanese wild boar population. The model was designed to estimate the impact of bait vaccination despite lack of data regarding the demography and movement of wild boar. Using our model, we solved the theoretical relationship between the impact of vaccination, the time-series change in the proportion of infected wild boar, and that of immunised wild boar. Using this derived relationship, the increase in antibody prevalence against CSF because of vaccine campaigns in 2019 was estimated to be 12.1 percentage points (95% confidence interval: 7.8-16.5). Referring to previous reports on the basic reproduction number (R0) of CSF in wild boar living outside Japan, the amount of vaccine distribution required for CSF elimination by reducing the effective reproduction number under unity was also estimated. An approximate 1.6 (when R0 = 1.5, target vaccination coverage is 33.3% of total population) to 2.9 (when R0 = 2.5, target vaccination coverage is 60.0% of total population) times larger amount of vaccine distribution would be required than the total amount of vaccine distribution in four vaccination campaigns in 2019., Competing Interests: The authors have declared that no competing interests exist.

A pilot animal disease surveillance program was implemented at four abattoirs in Phnom Penh, Cambodia, between October 2019 and January 2020. A total of 1141 samples were collected from 477 cattle and 664 swine. Serological testing was performed using commercial antibody ELISA kits for zoonotic and high-impact animal diseases, namely brucellosis, Q fever, classical swine fever (CSF), porcine reproductive and respiratory syndrome (PRRS) and African swine fever (ASF). Only two samples tested positive for Brucella antibodies (0.2%, 95% CI 0.4-0.6, n = 1141). The seroprevalence of Q fever was 0.8% (95% CI 0.3-2.1, n = 477) in the cattle samples, while CSF, PRRS and ASF in pigs were 55.4% (95% CI 51.6-59.2, n = 655), 81.2% (95% CI 78.1-84.0, n = 655) and 2.6% (95% CI 1.6-4.1, n = 664), respectively. All 38 doubtful and 17 positive ASF antibody ELISA samples were negative when tested by real-time PCR. Univariate analyses demonstrated that the factor significantly associated with positive results of ASF was the abattoir location (p-value = 0.002). Based on logistic regression models, significant risk factors for CSF were province of origin (p-value = 1.7 × 10 -6 ), abattoir (p-value = 3.6 × 10 -11 ) and PRRS positivity (p-value = 0.004), and for PRRS were province of origin (p-value = 0.0004) and CSF positivity (p-value = 0.001). In conclusion, the seroprevalences of zoonotic diseases in this study were very low. The high prevalence of CSF and PRRS antibodies were most likely the result of vaccination. All ASF seropositive pigs, including those that gave equivocal results, originated from large-scale Cambodian-based commercial farms, as well as Thailand, which raises questions about possible illegal vaccination or low-pathogenicity ASF variants. The pilot abattoir serological surveillance program described here has the potential to provide a sentinel for incursions of novel and endemic pathogens, although further work is required to demonstrate its capacity to provide information on the longitudinal disease trends., (© 2022. The Author(s).)

African swine fever (ASF) and classical swine fever (CSF) are two major transboundary animal diseases of swine with important socioeconomic consequences at farm, subnational and national level. The objective of this study was to evaluate the direct cost of outbreaks and their control at country/regional level in four countries: namely CSF in Colombia in 2015-2016, the retrospective cost of ASF in the Philippines in 2019 and in a province of Vietnam in 2020 and a hypothetical ASF scenario in one region in North Macedonia, using the newly developed Outbreak Costing Tool (OutCosT). The tool calculates the costs of 106 different items, broken down by up to four types of farms, and by who assumes the cost (whether veterinary services, farmers or other stakeholders). The total cost of CSF in Colombia was US$ 3.8 million, of which 88% represented the cost of the vaccination campaign. For ASF, there were wide differences between countries: US$ 8,26,911 in Lao Cai (Vietnam), US$ 33,19,666 in North Macedonia and over US$ 58 million in the Philippines. While in the Philippines and Vietnam, 96-98% of the cost occurred in the affected farms, the highest expenditure in North Macedonia scenario was the movement control of the neighbouring and at-risk farms (77%). These important differences between countries depend on the spread of the disease, but also on the production systems affected and the measures applied. Apart from the financial cost, these diseases have other negative impacts, especially in the livelihoods of smallholder farms. The OutCosT tool also allows users to evaluate qualitatively other important aspects related to the epidemics, such as the impact on human health, the environment, animal welfare, socioeconomic vulnerability, trading and political response. OutCosT, which is a FAO corporate tool (available online at: https://www.fao.org/fileadmin/user&#95;upload/faoweb/animal-health/OutCosT&#95;PIG.xlsx), can be an important tool to support country authorities to rapidly respond to a swine disease outbreak by estimating the associated costs and for advocacy purposes to mobilize resources at national or international levels., (© 2022 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

Classical swine fever (CSF) is a highly contagious swine-specific disease which may have a huge economic impact for porcine production. CSF is caused by a virus belonging to the Pestivirus genus, which has expanded for the past 5 years with the discovery of new species whose genetic proximity to the CSF virus could further complicate laboratory diagnosis. The various forms of the disease, and in particular the increased frequency of attenuated forms, linked to an evolution of CSF virus strains towards a reduction in their virulence, delay clinical diagnosis. Thus, a long period may elapse before an outbreak is detected, allowing the virus to circulate longer, with the risk of spreading to distant geographical areas. Efforts must be maintained in terms of surveillance and diagnostic tools development in order to detect CSF virus infection early and thus limit the spread of the disease and facilitate control measures.

Classical swine fever (CSF) is a viral disease that causes enormous economic losses in the swine industry in endemic countries including China. The aims of the current study were to describe the spatial distribution of annual CSF reports in China from 2005 to 2018, identify spatiotemporal clusters of annual CSF reports during this time period and to investigate the correlations between climate factors (rainfall, wind speed, temperature, vapour pressure and relative humidity) and the occurrence of CSF outbreaks. The strongest (Moran's index > 0.19), significant (p < .05) spatial clustering of reported outbreaks was observed during the first 4 years of the study period. This clustering was apparent in the four southern provinces of Guizhou, Guangxi, Guangdong and Yunnan. Five of the six significant (p ≤ .0001) spatiotemporal clusters occurred during the period 2005-2012. These were widely dispersed, with four clusters persisting for only 1 or 2 years, whereas two clusters (Jiangxi and Yunnan) persisted for 8 and 7 years, respectively. As a result of implementation of a national animal disease control plan and increasing coverage of vaccination, CSF outbreaks in China have generally been controlled and reduced, becoming sporadic in most provinces by 2018. We also confirmed that low relative humidity and high wind speed were significant weather variables associated with the occurrence of CSF. Furthermore, our study has confirmed that CSF is still endemic in some Chinese provinces, and we recommend that the national CSF control protocol be updated and standardized., (© 2022 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

Classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Routine surveillance serology for CSF and PRRS viruses is critical to maintaining the health status of sow farms in Hunan Province, which is one of the top pig production provinces in China. The aim of our study was to investigate the serological statistics of CSF virus (CSFV) and PRRS virus (PRRSV) in Hunan Province. The cohort serum samples were collected from vaccinated and unvaccinated pigs. Our findings showed that the average rates of CSFV and PRRSV antibody seropositivity were 82.2% (95% CI: 80.1-84.3) and 84.8% (95% CI: 82.5-87.1), respectively, in the immunized group and that these rates were higher than those in the unvaccinated group (58.6% for CSFV and 47.8% for PRRSV). Additionally, the level of CSFV antibody in piglet serum declined gradually with age, whereas PRRSV-specific antibody level increased initially (1 to 2 weeks old) and then declined with age (2 to 4 weeks old). In summary, we investigated the difference in CSFV/PRRSV antibody levels among piglets at various weeks old (1 to 4 weeks) to further establish the duration of maternal immunity in piglets. In addition, routine monitoring of CSFV/PRRSV antibodies in immunized pigs was carried out to evaluate the efficacy of vaccination., (Copyright© by the Polish Academy of Sciences.)

Classical swine fever is a disease that infects wild boars and pigs and had a significant negative economic impact on the swine industry. Oral vaccination is an effective method for controlling classical swine fever. However, information on oral vaccination program has been limited, and its efficiency has not been clarified in Japan. The purpose of this study was to determine the seasonal variation in factors affecting the ingestion of oral vaccines by wild boars. The Gifu Prefecture oral vaccination program was initiated in March 2019, and by February 2021, six seasonal programs had been conducted. We investigated the relationship between the ingestion of oral vaccines by wild boar and pre-baiting, vaccination event, environmental and topographical factors in six vaccination events in three seasonal programs (summer 2019, winter 2019-2020, and spring 2020). This study showed that pre-baiting and the repeated vaccination events were more important factors for the ingestion of oral vaccines by wild boars than topographical and land use factors. Thus, it is a possibility that habitat selection of wild boars is irrelevant in increasing the feeding rate of wild boars on oral vaccines. Consequently, wildlife managers should not only conduct pre-baiting and repeated vaccination events, but also identify areas where wild boars are more abundant immediately prior to oral vaccination programs. To increase the effectiveness of vaccination, it is important for wildlife managers to first implement estimating wild boar density in their habitat areas, followed by efficient oral vaccination programs depending on their densities. Thereafter, they should specifically consider the influence of ingestion by other species and differences in feeding rates by age class., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Pig farming in Ecuador represents an important economic and cultural sector, challenged by classical swine fever (CSF). Recently, the National Veterinary Service (NVS), has dedicated its efforts to control the disease by implementing pig identification, mandatory vaccination against CSF and movement control. Our objective was to characterise pig premises according to risk criteria, to model the effect of movement restriction strategies and to consider the temporal evolution of the network. Social network analysis (SNA), SIRS (susceptible, infected, recovered, susceptible) network modelling and temporal analysis were used. The network contained 751,003 shipments and 6 million pigs from 2017 to 2019. Participating premises consisted of 144,118 backyard farms, 138 industrial farms, 21,337 traders and 51 markets. The 10 most influential markets, in the Andean highlands, received between 500 and 4600 pigs each week. The 10 most influential traders made about 3 shipments with 17 pigs per week. Simulations without control strategy resulted in an average CSF prevalence of 14.4 %; targeted movement restriction reduced the prevalence to 7.2 %, while with random movement restriction it was 13 %. Targeting the top 10 national traders and markets and one of the high-risk premises in every parish was one of the best strategies with the surveillance infrastructure available, highlighting its major influence and epidemiological importance in the network. When comparing the static network with its temporal counterpart, causal fidelity (c = 0.62) showed a 38 % overestimation in the number of transmission paths, also traversing the network required 4.39 steps, lasting approximately 233 days. In conclusion, NVS surveillance strategies could be more efficient by targeting the most at-risk premises, and in particular, taking into account the temporal information would make the risk assessment much more precise. This information could contribute to implement risk-based surveillance reducing the time to eradicate CSF and other infectious animal diseases., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Classical swine fever virus (CSFV), the causative agent of classical swine fever (CFS), is a highly contagious disease that poses a serious threat to Chinese pig populations., Objectives: Many provinces of China, such as Shandong, Henan, Hebei, Heilongjiang, and Liaoning provinces, have reported epidemics of CSFV, while the references to the epidemic of CSFV in Yunnan province are rare. This study examined the epidemic characteristics of the CSFV in Yunnan province., Methods: In this study, 326 tissue samples were collected from different regions in Yunnan province from 2015 to 2021. A reverse transcription-polymerase chain reaction (RT-PCR), sequences analysis, and phylogenetic analysis were performed for the pathogenic detection and analysis of these 326 clinical specimens., Results: Approximately 3.37% (11/326) of specimens tested positive for the CSFV by RT-PCR, which is lower than that of other regions of China. Sequence analysis of the partial E2 sequences of eleven CSFV strains showed that they shared 89.0-100.0% nucleotide (nt) and 95.0-100.0% amino acid (aa) homology, respectively. Phylogenetic analysis showed that these novel isolates belonged to the subgenotypes 2.1c and 2.1d, with subgenotype 2.1c being predominant., Conclusions: The CSFV was sporadic in China's Yunnan province from 2015 to 2021. Both 2.1c and 2.1d subgenotypes were found in this region, but 2.1c was dominant., Competing Interests: The authors declare no conflicts of interest., (© 2022 The Korean Society of Veterinary Science.)

A classical swine fever (CSF) epidemic has been ongoing in Japan since September 2018. The outbreak started in Gifu Prefecture and involved 21 prefectures by the end of October 2020, posing a serious threat to pork industries. The present study was conducted to capture the spatiotemporal dynamics of CSF in Japan and assess the geographic range of the CSF vaccination on pig farms. First infection dates were collected for wild boars and on swine farms by prefecture. A simple statistical model was used to describe the spatiotemporal dynamics of CSF, describing the infection risk in wild boars and the subsequent transmission hazards to swine farms for 47 prefectures. Because the spatial transmission mechanisms and wild boar population dynamics involved substantial uncertainties, 16 models were applied to the empirical data. Estimated hazard parameters were used to predict the risk of infection on swine farms by 15 December 2020 to explicitly evaluate the governmental recommendation for vaccinations on pig farms by prefecture in light of the predicted infection risk in domestic pigs. The best-fit model for the wild boars indicated that transmission occurred via neighbouring prefectures and involved seasonality. The estimated conditional hazard was 0.008 (95% confidence interval [CI]: 0.001-0.014) per day for infections transmitted from wild boars to swine farms, and the median time from wild boar infection to swine farm infection was 129.4 days (95% CI: 69.5-935.0). Our prediction indicated that prefectures connected by land to those with wild boar infections had a higher risk of infection on swine farms. CSF transmission in Japan likely progressed diffusively via wild boar movement, and tracking wild boar infections may help determine the risk of infection on swine farms. Our risk map highlights the importance of deciding vaccination policies according to predicted risk., (© 2021 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

The classical swine fever virus is the etiologic agent of one of the diseases with the greatest impact on swine farming worldwide. An extensive area of Brazil is considered free of the disease, but some states in Northeast Brazil have registered outbreaks since 2001. The objective of this study was to analyze the genetic variations of the virus and its spread over time and space. Partial sequences of the viral E2 protein obtained from samples collected during the Brazilian outbreaks were compared with sequences from the GenBank database (NCBI). The results demonstrated the continuous presence of the virus in the state of Ceará, with diffusion to at least two other states. The Brazilian Northeast virus presents specific polymorphisms that separate it from viruses isolated in other countries., (© 2022. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

After 26 years, another classical swine fever virus (CSFV) outbreak in domestic pigs and wild boars occurred in Japan 2018. Herein, we investigated the entry and the spatial dynamics of the CSFV outbreak in Japan using the nearly complete genomes of strains isolated from both wild boars and domestic pigs during this epidemic. Phylogenetic analysis showed that the most recent common ancestor (MRCA) of the Japanese lineage emerged 146 days (95% highest posterior density (HPD): 85-216 days) before the index case was detected. Based on epidemiological analysis, the period for the 95% HPD was 1 month earlier than the time of virus introduction into the index farm. The disease mainly spreads to the adjoining regions during the epidemic, with no spread to the nonadjacent regions. This result indicates that human activities, such as the movement of vehicles, contributed to the infection spread. As cases occurred in nonadjacent regions, the MRCA for the epidemic in the Saitama prefecture was estimated to have emerged 93 days before the date of detection in the initial farm in this region. Similarly, the MRCA for the epidemic in Okinawa prefecture, more than 1,300 km away from the other infected regions, was estimated to have emerged 34 days before the date of detection in the region's primary farm. Therefore, our results indicate that if exotic diseases emerge after a long period of absence or in a disease-free country, a longer period of time will elapse before detection, resulting in further spread. Additionally, subsequent infections occurring in regions distant from the original infected region will require less time for detection than in the original region. This study provides valuable insights into a CSFV outbreak that occurred in a previously CSFV-free country and thus beneficial in enhancing producers' awareness and allow for better preparation for infections., (© 2021 Wiley-VCH GmbH.)

Infection with the classical swine fever virus (CSFV) causes a disease in pigs that ranges from a hyperacute form in which animals die in a few hours to subclinical disease. Due to this wide range of virulence, several complementary surveillance strategies should be implemented for the early detection of the disease. The objective of the present study was to determine the sensitivity of the surveillance system to detect CSFV outbreaks in a free zone (Zone 1) and in a zone undergoing an eradication process (Zone 2) in Colombia. Stochastic scenario tree models were used to describe the population and surveillance structures and to determine the probability of CSFV detection. The total sensitivity of the surveillance system in the case of a single infected farm in Zone 1 was 31.4% (CI 95%: 7.2-54.1) and in the case of 5 infected farms was 85.2% (CI 95%: 67.3-93.7), while in Zone 2 the sensitivities were 27.8% (CI 95%: 6.4-55.1) and 82.5% (CI 95%: 65-92.9), respectively. The on-farm passive surveillance shows the highest sensitivity for detection of a single CSFV infected farm in both zones (22.8% in Zone 1 and 22.5% in Zone 2). The probability of detection was higher in a family / backyard premise than on a commercial farm in both zones. The passive surveillance at slaughterhouse had a sensitivity of 5.3% and 4.5% for the detection of a single infected farm in Zone 1 and 2, respectively. Active surveillance presented a range of sensitivity between 2.2% and 4.5%. In conclusion, the sensitivity of the surveillance in the two studied zones was quite high, one of reasons for this good sensitivity being the sentinel network based on the voluntary participation of 5,500 collaborators that were trained for the identification and notification of diseases of national interest., (© 2021 Wiley-VCH GmbH.)

In 2018, classical swine fever (CSF) re-emerged in the Gifu Prefecture, central Japan, causing an on-going outbreak among wild boars and domestic pigs in the country. Consequently, oral vaccination for wild boar and compulsory vaccination for pig farms started in 2019. We have previously shown that, before vaccination in the Gifu Prefecture, the presence of CSF-infected wild boar near pig farms increased the risk of CSF transmission. This study aimed to re-evaluate the transmission risk from wild boars to pig farms under a vaccination program. The effectiveness of vaccination was evaluated by comparing the transmission risk estimated before and after the implementation of vaccinations. In this study, we focused on two affected areas, the Kanto (eastern Japan) and Kinki (west-central Japan) regions, in which eight of 11 infected farms were detected between the start of pig farm vaccinations and April 2021. Wild boar surveillance data from an area within a 50-km radius from the infected farms were used for analysis, consisting of 18,870 1-km grid cells (207 infected cells) in the Kanto region, and 15,677 cells (417 infected cells) in the Kinki region. The transmission rates in the post-vaccination period in the Kanto and Kinki regions were much lower than that in the pre-vaccination period in the Gifu Prefecture. The values of transmission kernels (h 0 , transmission rate at 0 km) in the Kanto and Kinki regions decreased to 1% of the transmission kernel in the pre-vaccination period. In the pre-vaccination period, the risk of infection within 300 days was almost 95 % when one infected grid cell was detected within 1 km of a pig farm. Meanwhile, in the post-vaccination period, the risk of infection within 300 days was approximately 5% when several infected cells were detected within 1 km of a pig farm. Considering the limited effect of oral vaccination for wild boar due to distribution limitations in the Kanto and Kinki regions, vaccination on pig farms may seems to have mainly reduced the transmission risk from wild boar. However, despite the implementation of vaccination, the risk of infection on pig farms remains present due to the immunity gap of weaning pigs. Therefore, strict biosecurity measures on pig farms and an appropriate vaccination program are required to prevent and control CSF spread., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Enhanced pig productivity on smallholder farms is recognised as a necessary strategy to enhance financial and food security in Timor-Leste where poverty and malnutrition are abundant. While poor pig health is recognised as a main constraint, information on pig herd health and management have not been thoroughly quantified. This study surveyed 120 pig owners (63 were female) and 352 of their pigs in Bacau and Bobonaro municipalities in 2018 to develop baseline information. Our analysis investigated three management systems among surveyed pig owners: confined management, characterised by permanent penning and/or tethering pigs (33.6%), semi-confined management (39.7%) and free-roaming management (27.7%). Free-roaming management was only observed in non-urban villages. Most inputs were limited across all management types with heavy reliance on cooked household scraps to feed pigs (84.7%), limited use of commercial feeds (5.1%), a lack of routine pen cleaning (73.8%), a lack of vaccination against classical swine fever (72.9%), limited use of para-veterinary services when pigs were sick (71.7%), and low treatment rates for pig skin diseases (10.3%) and intestinal parasites (8.7%). A high use of uncontrolled breeding (79.1%) was identified, accompanied by a limited knowledge of oestrus (20.7%) and gestation length (24.1%). Low output was observed with animals mainly sold when money is needed or when they were old. There was poor health with high piglet mortality rate (22.4-24.4%), moderate rates of current illness (22.4%), common occurrence of mites (12.2%), and high faecal presence of A. suum (29.0%), T. suis (10.2%), and S. ransomi (22.7%). To overcome the widespread constraints to productivity affecting all management systems, and to limit the impacts of highly infectious and often fatal African swine fever which was first reported in Timor-Leste pigs in September 2019, improved animal health and veterinary support, and education on pig management and suitable available nutrition sources are needed., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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.)

A retrospective investigation of pig tissue samples from different classical swine fever virus (CSFV) outbreaks was undertaken employing RT-PCR for possible coinfection with other swine viruses. Four samples from three different outbreaks were found to be coinfected with Japanese encephalitis virus (JEV). Phylogenetic analysis was done based on complete E gene sequenced from all four coinfected samples. This revealed a new introduction of a divergent subgroup of JEV genotype I in India. This is the first report of detection of coinfection of JEV and CSFV in pigs and the first incidence of JEV genotype I in pigs in India., (© 2020 Wiley-VCH GmbH.)

Although RNA viruses exhibit extensive sequence diversity, the mutation rate must be limited to ensure protein functions that maintain the viral life cycle. Here, we compared the whole genome sequences of 150 isolates of classical swine fever virus (CSFV), obtained from a single epidemic that occurred in Japan during 2018-2020. After the detection of the first case, the disease spread among both farm pigs and wild boars and caused severe impact on the pig industry. To evaluate the diversification of the CSFV genome that eliminated mutations negatively affecting viral transmission, the substitution sets inherited by at least two isolates were separately evaluated as shared single nucleotide variants (SNVs) or shared single amino acid variants (SAVs). Comparisons of 12 protein-coding regions indicated that the percentages of SNVs and SAVs in the multifunctional nonstructural protein NS3 were the lowest, and shared SAVs were not detected in another nonstructural protein, NS4A. This demonstrated purifying negative selection suppressing changes in the protein sequences of NS3 and NS4A during virus transmission in the field. In contrast, a high possibility of nonsynonymous substitution among shared SNVs was detected only in genes encoding the secreted protein E rns and the nonstructural protein NS2, suggesting positive selection during the epidemic. Mapping of shared SAVs to the three-dimensional structure of E rns revealed that shared SAVs were not present in the substrate-binding sites but were instead localized to the peripheral region of the protein. These data will support efforts toward the development of diagnostic methods, recombinant vaccines, and antiviral agents targeting conserved and indispensable viral genes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

There is a possibility that classical swine fever (CSF) virus outbreak has negative impacts on wild boar. To adequately manage native wild boar populations, wildlife managers need to gather the field data on wild boar and implement population management practices. We aimed to report the relative abundance index of wild boar before and after this outbreak. Our results showed that relative abundance index declined from 2017 (8.88 wild boars/100 trap days) to 2019 (2.03 wild boars/100 trap days), because of the negative impact of this virus and continuous culling programs. Although the eradication risk from the synergistic effect is low, wildlife managers need to consider the relationship between the trade-off between the risk of CSF and the conservation ecology risk of native species eradication.

Background: Classical swine fever (CSF) is a contagious disease of pigs and wild boars that is transmitted through direct/indirect contact between animals or CSF virus-contaminated fomites. When the disease re-emerged in 2018 in Japan, a CSF-infected wild boar was reported shortly after the initial pig farm outbreak; subsequently, the disease spread widely. To control the disease spread among wild boars, intensive capturing, fencing, and oral bait vaccination were implemented with concomitant virological and serological surveillance. This study aimed to describe the disease spread in the wild boar population in Japan from September 2018, when the first case was reported, to March 2020, based on the surveillance data. We conducted statistical analyses using a generalized linear mixed model to identify factors associated with CSF infection among wild boars. Moreover, we descriptively assessed the effect of oral bait vaccination, which started in March 2019 in some municipalities in the affected areas., Results: We observed a faster CSF infection spread in the wild boar population in Japan compared with the CSF epidemics in European countries. The infection probability was significantly higher in dead and adult animals. The influence of the multiple rounds of oral bait vaccination was not elucidated by the statistical modeling analyses. There was a decrease and increase in the proportion of infected and immune animals, respectively; however, the immunization in piglets remained insufficient after vaccination for 1 year., Conclusions: Conditions regarding the wild boar habitat, including forest continuity, higher wild boar population density, and a larger proportion of susceptible piglets, were addressed to increase the infection risk in the wild boar population. These findings could improve the national control strategy against the CSF epidemic among wild boars.

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

Pork accounts for almost one-third of the meat consumed worldwide. Infectious diseases have a marked impact on pig production. Epidemiological indicators are considered the most useful criteria in decision-making; however, a health status assessment remains a challenge at the national and regional levels. This study proposes a health index including herd-losses, morbidity, fatality, and type of diseases, to rate the health situation in a region or country; it contributes to assessing the effectiveness of control, damage manifestation, and trends. It is a multidimensional index with a structure of triads and simple quantitative, semi-quantitative, and qualitative expressions that use flexible and dynamics limits. With it, we analyzed twenty-one countries in 2005-2018, focusing on African swine fever, classical swine fever, foot-mouth-disease, and porcine respiratory and reproductive syndrome, diseases that caused 72% of the morbidity. Our multidimensional approach estimates farm, local, and regional impact from infectious agents and outbreaks, and apprises trends aiming to be useful to control measures, strategic actions, and animal health policies.

Classical swine fever (CSF) is an endemic disease in southeastern Asia and is one of the most important swine diseases in Vietnam. This study was conducted to characterize the pathology of natural cases of CSF in northern Vietnam in 2018 and their genetic prevalence. A total of 10 representative pigs were collected from four provinces (Hung Yen, Ha Noi, Quang Ninh and Thai Binh) during five outbreaks and examined pathologically. The gross and histopathological findings showed the disease was expressed as the acute or the subacute to chronic form of CSF, depending on the age of the animals. The most consistently observed lesions associated with infection by the classical swine fever virus (CSFV) included lymphoid depletions in tonsils, lymph node and spleen; histiocytic hyperplasia in spleen; cerebral haemorrhage; perivascular cuffing in the brain; renal erythrodiapedesis; urothelial vacuolation and degeneration and interstitial pneumonia. The immunohistochemical findings showed a ubiquitous CSFV antigen mainly in the monocytes/macrophages and in the epithelial and endothelial cells in various organs. CSFV neurotropism was also found in the small neurons of the cerebrum and the ganglia of the myenteric plexus. Analysis of the full-length envelope protein (E2) genome sequence showed that all strains were genetically clustered into subgenotype 2.5, sharing a nucleotide identity of 94.0%-100.00%. Based on the results of this study, the strain was categorized as a moderately virulent CSFV., (© 2020 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Classical swine fever virus (CSFV) causes one of the most critical diseases in the porcine industry worldwide. In Brazil, the first description of the infection was reported in 1888, and the national recognition of the first free zone (FZ) occurred in 2001. Brazil has been recently recognized (2015-2016) by the World Organisation for Animal Health (OIE) with an FZ involving 15 states and the Federal District, corresponding to 95% of the industrial production of pigs in the country, and a non-free zone (NFZ), comprised by the North and Northeast regions of the country, with approximately 18% of the national pig herd and 5% of industrial production. This review aims to describe the history, the control and eradication actions, the recent occurrence of outbreaks in the NFZ, and the results obtained by the surveillance systems' action in the FZ for CSF in Brazil since its creation. In the passive surveillance system, the notification of the suspect cases of classical swine fever (CSF) is mandatory while in the active surveillance system adopted in the FZ consists of serological monitoring of certified swine breeding farms (CSBFs), intensive pig farming (IPF), non-technified pig herds (NTPig), surveillance in slaughterhouses and monitoring the populations of wild pigs. In this region, the last outbreaks of the disease occurred in 1998, while in the NFZ, 28 outbreaks were detected from 2005 to 2017, with an apparent lethality rate of 93.96% (840/894). However, in 2018 and 2019, 68 new outbreaks were registered with an apparent lethality rate of 75.05% (1095/1459). Therefore, in 2019, the Brazil CSF-Free Strategic Plan was created to eradicate the infection from the country's NFZ, since outbreaks in this region present a risk of reintroducing the disease FZ. Finally, differences in characteristics between the regions show factors that still need to be considered for the construction of a robust surveillance system in the NFZ and some improvements in the FZ. Thus, the control of CSF throughout the Brazilian territory requires strict sanitary guidelines, promoting animal health and, consequently, the national production chain's competitiveness.

Classical swine fever (CSF) is among the most relevant viral epizootic diseases of swine. Due to its severe economic impact, CSF is notifiable to the world organisation for animal health. Strict control policies, including systematic stamping out of infected herds with and without vaccination, have permitted regional virus eradication. Nevertheless, CSF virus (CSFV) persists in certain areas of the world and has re-emerged regularly. This review summarizes the basic established knowledge in the field and provides a comprehensive and updated overview of the recent advances in fundamental CSFV research, diagnostics and vaccine development. It covers the latest discoveries on the genetic diversity of pestiviruses, with implications for taxonomy, the progress in understanding disease pathogenesis, immunity against acute and persistent infections, and the recent findings in virus-host interactions and virulence determinants. We also review the progress and pitfalls in the improvement of diagnostic tools and the challenges in the development of modern and efficacious marker vaccines compatible with serological tests for disease surveillance. Finally, we highlight the gaps that require research efforts in the future., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Emergency surveillance following an outbreak of transboundary animal diseases such as classical swine fever (CSF), is conducted to find another new infection as early as possible. Although larger sample sizes can help achieve higher disease surveillance sensitivity, the sample size is limited by the availability of resources in an emergency situation. Moreover, the recent CSF outbreak reported in Japan was associated with fewer clinical signs; this emphasizes the importance of detecting infected farms by surveillance. In this study, we aimed to identify effective and labor-efficient sampling methods showing high probabilities of detecting infection, by simulating infection and sampling in pigsties. We found that impartial sampling, which involves selection of pigs to be sampled from the four corners and the center of the pigsty, and random sampling showed comparable probabilities of detection. Impartial sampling involves sample collection without pig identification and random selection. Owing to its simplicity, impartial sampling is labor-efficient and thus a possible substitute for random sampling. In a group-housing pigsty, testing five pigs from five pens showed a higher detection probability than testing five pigs from one pen. These results suggest preferable surveillance methods for conducting emergency surveillance of infectious diseases., Competing Interests: The authors have declared that no competing interests exist.

Given the importance of pork in the Bhutanese diet and to enhance food security, the Government of Bhutan has generated policies to promote development of the swine sector in the country. One of the main threats to swine farming is classical swine fever (CSF), a transboundary disease of wild and domestic swine thought to be enzootic in the country. In 2018, three outbreaks of CSF were notified in Bhutan. The type of animals, their vaccine status, and the aftermath of these outbreaks highlight the interplay of epidemiological and context-specific factors that may result in CSF undermining the emerging Bhutanese swine sector. This communication reports on the CSF outbreaks of 2018, discusses some of the challenges posed by these events, and proposes some research priorities.

A cross-sectional study was undertaken to identify factors associated with herd-level seropositivity to Classical Swine Fever (CSF) in smallholder pig farms in West Timor, Indonesia. Questionnaires were distributed to 240 pig farmers from 8 villages in two districts to collect information about farm structure and herd information, reproductive management and performance, husbandry, pig introductions and exits, health status, farmers' knowledge and history of vaccination. Three risk factors were found to be associated with the presence of antibodies to CSF in the herd in a multivariable logistic regression model. Seropositivity was associated with the introduction of pigs in the 12-month period preceding the survey (OR 4.78, 95% CI: 1.46, 15.71). Farmers who kept goats were 3.42 (95% CI: 1.20, 9.81) times more likely to have seropositive pigs than farmers without goats. Herds that had been vaccinated against CSF were also 2.33 (95% CI: 1.10, 5.12) times more likely to be seropositive than non-vaccinated herds. This latter positive association is likely to be as a result of antibodies induced by vaccination rather than a true risk factor for infection. The results of the questionnaire highlighted the lack of implementation of biosecurity measures by smallholder farmers in West Timor, which has the potential to increase the risk of their pigs to CSF, as well as other diseases., (Crown Copyright © 2020. Published by Elsevier Ltd. All rights reserved.)

Classical swine fever (CSF) is an infectious viral disease caused by an RNA virus belonging to the Pestivirus genus. A total of 134 outbreaks of CSF have occurred in the last seven years in the North of Colombia. The objective of this study was the characterization of the herds affected by CSF from 2013 to 2018. Most of the outbreaks (95%) occured in backyard piggeries. The principal causes of transmission of CSF were the introduction of infected pigs (38%), movements of people (37%) and unknown origin (13%). The epidemiological relationships with 15 affected farms explained 31 outbreaks. The overall attack and mortality rates were 39% and 32%, respectively. The main clinical signs were high fever (67%), incoordination of movements (54%), and prostration (52%). Seventy-three percent of the herds had not been vaccinated against CSF and 17% had been only partially vaccinated. A spatio-temporal analysis, using a Poisson regression model, revealed two clusters with high risk; the first and largest one from 2014 to 2016 had a relative risk (RR) of 13.4 and included part of the departments of Atlántico, Bolívar, Cesar, La Guajira, Norte de Santander, Magdalena and Sucre; and the second cluster (RR = 9.6 in 2016) included municipalities in the north of the department of Cordoba., Competing Interests: The authors declare that there is no competing interest regarding the publication of this paper.

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

The genus Pestivirus comprises globally distributed members of the family Flaviviridae, which cause severe losses in livestock. The most common species of the genus are bovine viral diarrhoea virus type 1 (BVDV-1) and type 2 (BVDV-2), classical swine fever virus (CSFV) and border disease virus (BDV). Recently, a novel ovine pestivirus was repeatedly detected in aborted lamb foetuses on a farm located in the Brescia Province (Italy). Complete genome characterization of this isolate showed that it was highly divergent from known pestivirus species and that it was genetically closely related to CSFV. The aim of this study was to determine the serological relatedness between the identified novel pestivirus and BVDV, BDV and CSFV selected strains for which homologous serum was available, by antigenic characterization performed using cross-neutralization assays. The serological relatedness was expressed as the coefficient of antigenic similarity (R). Both field and specific antisera raised against the ovine pestivirus neutralized the CSFV reference strain Diepholz with titres significantly higher than those specific for the BDV and BVDV strains. Furthermore, the calculated R values clearly indicated that the novel ovine pestivirus is antigenically more related to CSFV than to ruminant pestiviruses, in agreement with the results of the genomic analysis. This would have severe consequences on CSFV serology in the event of a switch to porcine hosts with implications for CSFV surveillance and porcine health management., (© 2020 Blackwell Verlag GmbH.)

In September 2018, classical swine fever (CSF) reemerged in Japan after 26 years' absence. The first case was detected at a pig farm in Gifu Prefecture, in the center of Japan, and the disease spread to both domestic pigs and wild boar (Sus scrofa). The spread of CSF in wild boar is extremely difficult to control and is thus a great threat to domestic pig farms, and understanding the transmission risk from wild boar to domestic pigs is essential to implement effective control measures that will prevent domestic pig infection. Therefore, this study elucidates the transmission risk from wild boar to domestic pigs by introducing a transmission kernel that is dependent on the distance between infected wild boar and pig farms, and then estimating the risk area of infection from wild boar by describing the transmission probability. The study used epidemiological data from Gifu Prefecture in the period from September 2018 to March 2019, including a total of 171 1-km grid cells where an infected wild boar was detected and pig farm data from 13 infected and 34 uninfected farms. The estimated infection risk area within 28 days matched well with the observed data. The risk area widened gradually during the epidemic, and at the end of March, the risk area extended over a range of approximately 75 km from east to west and 40 km from north to south (almost 3000 km 2 ). Ten out of the 13 infected farms and four out of the 34 uninfected farms were located within the high-risk area (>60 % infection probability). In contrast, one infected farm and 18 uninfected farms were located within the low-risk area (<5 % infection probability). When several infected grid cells were detected within 5 km of a pig farm, the risk of infection from wild boar within 28 days was more than 5 %. This analysis provides an estimate of the potential spatial range over which CSF virus can spread between wild boar and domestic pig farms, and can be used to inform the early detection of CSF-suspected pigs and the strengthening of biosecurity measures that will effectively prevent and control the disease based on the infection risk level., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: Australia is currently regarded as free of classical swine fever (CSF), a highly contagious disease of pigs caused by a pestivirus. This study aimed to provide additional evidence that the Victorian domestic pig population is free of CSF., Design: A structured representative sero-prevalence survey of Victorian domestic pigs at slaughter., Method: Three-hundred and ninety-one pigs from 23 holdings were sampled at the time of slaughter between March 2016 and October 2017., Results: All samples were negative for CSF virus Ab on ELISA. Because of uncertainty in the sensitivity of the CSF Ab ELISA, estimates of the true prevalence of CSF were calculated using Bayesian methods. The median and upper bound of the 95% credible intervals for the true prevalence of CSF was zero when the diagnostic sensitivity of the CSF Ab ELISA was assumed to range from 0.75 to 0.95., Conclusion: These results provide evidence that the population of domestic pigs in Victoria in 2016-2017 was free of CSF., (© 2019 Australian Veterinary Association and State of Victoria.)

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.)

After the unintentional vaccination of the LOM vaccine strain in 2014, classical swine fever virus (CSFV) reemerged in naïve pig herds on Jeju Island, South Korea, which had been a CSF-free region with a non-vaccination policy for a decade. Since the re-emergence, endemic outbreaks of CSFV have occurred in the island, causing enormous damage to provincial pig farms. The present study reports the complete genome sequences and molecular characterization of the LOM-derived field CSFV strains responsible for the current outbreaks on Jeju Island. The emergent Jeju LOM-derived isolates shared 98.9%-99.7% and 98.7%-99.0% nucleotide sequence identity at the E-gene and whole-genome levels compared to the LOM vaccine strain respectively. Genetic and phylogenetic analyses indicated that the CSFV field isolates were closest to the LOM strains, but appeared to have undergone substantial evolution. The total number of nucleotide and amino acid differences between the LOM vaccine strain and LOM-derived field isolates ranged from 111 and 28 to 148 and 42. These variations were found to be widely distributed throughout the genome and particularly accumulated in non-structural proteins, which might be associated with the potential for LOM to revert to its original low pathogenic form and subsequent horizontal transmission in Jeju swine herds. These data improve our knowledge regarding safety of the LOM vaccine and inherent risk of reversion to natural virulence in host animals., (© 2019 Blackwell Verlag GmbH.)

Classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circoviruses (PCV2 and PCV3) are economically important swine viruses that cause reproductive failure and/or respiratory symptoms in pigs. However, the co-infection status of these viruses in Chinese swine herds is not well clarified. In this study, we evaluated the co-infection of these four viruses in 159 pigs collected from 63 herds in eight regions of China from 2016 to 2018. CSFV, PRRSV, PCV2 and PCV3 were detected in 14, 56, 43 and 4 of the pigs, respectively. The percentage of singular infections was 32.71%, while the percentages of dual infections and multiple infections were 15.72% and 3.15%, respectively. The E2 of CSFV, ORF5 of PRRSV, ORF2s of PCV2 and PCV3 from all positive samples were determined and used for phylogenetic analyses. E2-based phylogenetic tree showed that all 14 CSFVs identified in this study belong to 2.1b subtype. ORF5-based phylogenetic tree showed that PRRSV2 is predominant in China while PRRSV1 can also be detected. In addition, 35, 16, 4 and 1 of our PRRSVs are clustered with highly pathogenic PRRSV2, NADC30-like PRRSV2, classical PRRSV2 and PRRSV1, respectively. ORF2-based phylogenetic trees showed that our PCVs are grouped with 2 PCV2 subtypes (PCV2d and PCV2b) and 3 PCV3 subtypes (PCV3a, PCV3b and PCV3c), respectively. Our results provide the latest co-infection status and the diversity of four important swine viruses in Chinese swine herds, which is beneficial for understanding the epidemiology of these viruses., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Classical swine fever (CSF) continues to be a devastating infectious disease for the swine industry in China and commonly exists as wild or atypical types. From June 3rd to October 3rd, 2018, outbreaks of typical CSF cases with mortality rates of 42-86% occurred in 11 swine herds in five cities of Guangdong province, and were confirmed by RT-PCR. Phylogenetic analyses based on the nucleotide sequences of full-length E2 genes showed that the CSFV isolates collected in Guangdong, 2018 grouped into sub-subgenotype 2.1c and formed a separate clade from previously identified 2.1c isolates. Sequence comparison further confirmed the distance between the novel emergent and previously identified 2.1c isolates, with shared 94.5-98.2% and 97.8-99.7% identities at the nucleotide and amino acid levels respectively. Furthermore, 2.1c isolates collected in 2018 from Guangdong province contained a unique amino acid substitution (K174R) in the E2 protein in comparison with other 2.1c representative strains and CSFV 2.1, 2.2, 2.3 strains. Of note, the novel emergent 2.1c isolates are neutralized by sera from C-strain vaccinated sows, indicating that C-strain is still efficacious for protection against field isolates of CSFV., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Two strains of classical swine fever virus (CSFV) (SRB/CSFV/1264/2005 and SRB/CSFV/6168/2006), producing serious clinical signs of disease during outbreaks in 2005 and 2006 in Serbia, were isolated on porcine kidney cells, and their complete genomes were determined by next-generation sequencing. This first complete genome characterization of Serbian CSFV strains provides new data about the evolution of CSFV in the Balkan region and enables further detailed phylogenetic studies of the various strains.

Pigs in Lao People's Democratic Republic are important for income and food security, particularly in rural households. The majority of pigs are reared in smallholder systems, which may challenge the implementation of any disease control strategies. To investigate risk factors for pig production diseases in such farming systems in the country a serological survey was conducted during 2011. A total of 647 pigs were sampled, accounting for 294 households in Luang Prabang and 353 in Savannakhet province representing upland and lowland, respectively. The results demonstrated that pigs in Lao PDR had antibodies against erysipelas (45.2%), CSF (11.2%), PRRS (8.6%), FMD O (17.2%) and FMD Asia 1, (3.5%). Differences in the housing systems influenced disease risk, for example, penned pigs had reduced odds of FMD and CSF, compared to those in scavenger systems. Pigs owned by farms using a sanaam (a communal area where pigs are kept for some time of the year) had 3.93 (95% confidence interval (CI): 1.09-14.7) times the odds of having pigs seropositive for FMD. Farms on which sudden piglet deaths had been experienced were more likely to have pigs seropositive for FMD O and erysipelas. These diseases constrain the development of village farming and the wider livestock industry due to their impact on productivity and trade. Vaccination coverage for FMD and CSF was low and there was a lack of national funding for livestock disease control at the time of the study. Further investigation into sustainable low-cost control strategies for these pathogens is warranted., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

The 5' UTR (n=102) and full-length E2 (n=37) genes of classical swine fever viruses (CSFVs) circulating in South Korea over the past 30 years (1987-2017) were examined to determine the evolutionary rate and estimated time of the most recent common ancestor (tMRCA). From 2000, the Korean classical swine fever (CSF) antigen changed from genotype 3 to 2, which comprises subgenotypes 2.1b (2002-2013) and 2.1d (2011-2017). There are genotypic variations in the full-length E2 gene of Korean CSFV genotypes 2.1b and 2.1d (seven separate amino acid substitutions); these are useful distinguishing markers. The mean substitution rate (×10 3 substitutions/site/year) for Korean CSFV was estimated to be 2.2088 (95% highest posterior density (HPD): lower, 1.7045; upper, 2.7574) and the mean tMRCA was estimated to be 1901 (95% HPD: lower, 1865; upper, 1933). The effective population size of Korean CSFV genotype 2 increased rapidly from 2002 to 2003, after which it remained constant. The occurrence of CSF in Korea is expected to decline in the future; however, it will likely be more prevalent in wild boar than in domestic pigs. Thus, there is a risk of transmission from wild boar to breeding pigs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Classical swine fever (CSF) is a globally significant disease of swine caused by classical swine fever virus. The virus affects the wild boars and pigs of all age groups, leading to acute, chronic, late-onset or in-apparent course of the disease. The disease causes great economic loss to the piggery industry due to mortality, stunted growth, poor reproductive performance, and by impeding the international trade of pig and pig products. In India, CSF outbreaks are reported from most of the states wherever pig rearing is practiced and more frequently from northeast states. In spite of the highly devastating nature and frequent outbreaks, CSF remained underestimated and neglected for decades in India. The country requires rapid and sensitive diagnostic tests for an early detection of infection to limit the spread of the disease. Also, effective prophylactics are required to help in control and eradication of the disease for the development of the piggery industry. This review looks into the economic impact; epidemiology of CSF highlighting the temporal and spatial occurrence of outbreaks in the last two decades, circulation, and emergence of the virus genotypes in and around the country; and the constraints in the disease control, with the aim to update the knowledge of current status of the disease in India. The article also emphasizes the importance of the disease and the need to develop rapid specific diagnostics and effective measures to eradicate the disease.