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The swine industry across the globe is recently facing a devastating situation imparted by a highly contagious and deadly viral disease, African swine fever. The disease is caused by a DNA virus, the African swine fever virus (ASFV) of the genus Asfivirus. ASFV affects both wild boars and domestic pigs resulting in an acute form of hemorrhagic fever. Since the first report in 1921, the disease remains endemic in some of the African countries. However, the recent occurrence of ASF outbreaks in Asia led to a fresh and formidable challenge to the global swine production industry. Culling of the infected animals along with the implementation of strict sanitary measures remains the only options to control this devastating disease. Efforts to develop an effective and safe vaccine against ASF began as early as in the mid-1960s. Different approaches have been employed for the development of effective ASF vaccines including inactivated vaccines, subunit vaccines, DNA vaccines, virus-vectored vaccines, and live attenuated vaccines (LAVs). Inactivated vaccines are a non-feasible strategy against ASF due to their inability to generate a complete cellular immune response. However genetically engineered vaccines, such as subunit vaccines, DNA vaccines, and virus vector vaccines, represent tailored approaches with minimal adverse effects and enhanced safety profiles. As per the available data, gene deleted LAVs appear to be the most potential vaccine candidates. Currently, a gene deleted LAV (ASFV-G-∆I177L), developed in Vietnam, stands as the sole commercially available vaccine against ASF. The major barrier to the goal of developing an effective vaccine is the critical gaps in the knowledge of ASFV biology and the immune response induced by ASFV infection. The precise contribution of various hosts, vectors, and environmental factors in the virus transmission must also be investigated in depth to unravel the disease epidemiology. In this review, we mainly focus on the recent progress in vaccine development against ASF and the major gaps associated with it.

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African swine fever (ASF) is a transboundary infectious disease that can infect wild and domestic swine and requires enhanced surveillance between countries. In Mozambique, ASF has been reported across the country, spreading between provinces, mainly through the movement of pigs and their by-products. Subsequently, pigs from bordering countries were at risk of exposure. This study evaluated the spatiotemporal distribution and temporal trends of ASF in swine in Mozambique between 2000 and 2020. During this period, 28,624 cases of ASF were reported across three regions of the country. In total, the northern, central, and southern regions presented 64.9, 17.8, and 17.3% of the total cases, respectively. When analyzing the incidence risk (IR) of ASF per 100,000 pigs, the Cabo Delgado province had the highest IR (17,301.1), followed by the Maputo province (8868.6). In the space-time analysis, three clusters were formed in each region: (i) Cluster A involved the provinces of Cabo Delgado and Nampula (north), (ii) Cluster B involved the province of Maputo and the city of Maputo (south), and (iii) Cluster C consisted of the provinces of Manica and Sofala (central) in 2006. However, when analyzing the temporal trend in the provinces, most were found to be decreasing, except for Sofala, Inhambane, and Maputo, which had a stationary trend. To the best of our knowledge, this is the first study to evaluate the spatial distribution of ASF in Mozambique. These findings will contribute to increasing official ASF control programs by identifying high-risk areas and raising awareness of the importance of controlling the borders between provinces and countries to prevent their spread to other regions of the world.

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Management and policy decisions are continually made to mitigate disease introductions in animal populations despite often limited surveillance data or knowledge of disease transmission processes. Science-based management is broadly recognized as leading to more effective decisions yet application of models to actively guide disease surveillance and mitigate risks remains limited. Disease-dynamic models are an efficient method of providing information for management decisions because of their ability to integrate and evaluate multiple, complex processes simultaneously while accounting for uncertainty common in animal diseases. Here we review disease introduction pathways and transmission processes crucial for informing disease management and models at the interface of domestic animals and wildlife. We describe how disease transmission models can improve disease management and present a conceptual framework for integrating disease models into the decision process using adaptive management principles. We apply our framework to a case study of African swine fever virus in wild and domestic swine to demonstrate how disease-dynamic models can improve mitigation of introduction risk. We also identify opportunities to improve the application of disease models to support decision-making to manage disease at the interface of domestic and wild animals. First, scientists must focus on objective-driven models providing practical predictions that are useful to those managing disease. In order for practical model predictions to be incorporated into disease management a recognition that modeling is a means to improve management and outcomes is important. This will be most successful when done in a cross-disciplinary environment that includes scientists and decision-makers representing wildlife and domestic animal health. Lastly, including economic principles of value-of-information and cost-benefit analysis in disease-dynamic models can facilitate more efficient management decisions and improve communication of model forecasts. Integration of disease-dynamic models into management and decision-making processes is expected to improve surveillance systems, risk mitigations, outbreak preparedness, and outbreak response activities.

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PSA é uma doença viral sistema e fatal, particular dos suídeos que acomete tanto os domésticos quanto silvestres (javalis). A depender da estirpe viral, a infecção pode resultar em ampla variedade de sinais clínicos, desde casos superagudos aos crônicos incluindo os portadores sãos (PENRITH et al., 2013). Estirpes patogênicas e virulentas causam doença superaguda letal caracterizada por morte súbita e aguda com sinais de hipertermia, hemorragia na pele e órgãos internos. Estirpes de moderada ou baixa patogenicidade e virulência, causam doença hemorrágica de diferentes intensidades e mortalidade mais baixa (± 30%). Em casos agudos, a morte ocorre, usualmente, depois de 3-10 dias da infecção e pode atingir taxas de 90% (EFSA, 2014). A profilaxia da Peste Suína Africana (psa) requer conhecimento de sua epidemiologia, que é o estudo dos mecanismos de transmissão em determinada área geográfica e os respectivos meios de profilaxia (THRUSFIELD, 2018). Significa conhecer o caminho que o vírus percorre na população de apamvet.com BOLETIM Apamvet 27 MOLÉSTIAS INFECCIOSAS animais suscetíveis para se perpetuar como espécie (DIXON; SUND; ROBERTS, 2019; CHENAIS et al., 2019).(AU)

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PSA é uma doença viral sistema e fatal, particular dos suídeos que acomete tanto os domésticos quanto silvestres (javalis). A depender da estirpe viral, a infecção pode resultar em ampla variedade de sinais clínicos, desde casos superagudos aos crônicos incluindo os portadores sãos (PENRITH et al., 2013). Estirpes patogênicas e virulentas causam doença superaguda letal caracterizada por morte súbita e aguda com sinais de hipertermia, hemorragia na pele e órgãos internos. Estirpes de moderada ou baixa patogenicidade e virulência, causam doença hemorrágica de diferentes intensidades e mortalidade mais baixa (± 30%). Em casos agudos, a morte ocorre, usualmente, depois de 3-10 dias da infecção e pode atingir taxas de 90% (EFSA, 2014). A profilaxia da Peste Suína Africana (psa) requer conhecimento de sua epidemiologia, que é o estudo dos mecanismos de transmissão em determinada área geográfica e os respectivos meios de profilaxia (THRUSFIELD, 2018). Significa conhecer o caminho que o vírus percorre na população de apamvet.com BOLETIM Apamvet 27 MOLÉSTIAS INFECCIOSAS animais suscetíveis para se perpetuar como espécie (DIXON; SUND; ROBERTS, 2019; CHENAIS et al., 2019).

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African swine fever (ASF) causes greater sanitary, social and economic impacts on swine herds than many other swine diseases. Although ASF was first described in 1921 and it has affected more than fifty countries in Africa, Europe and South America, several key issues about its pathogenesis, immune evasion and epidemiology remain uncertain. This article reviews the main characteristics of the causative virus, its molecular epidemiology, natural hosts, clinical features, epidemiology and control worldwide. It also identifies and prioritizes gaps in ASF from a horizontal point of view encompassing fields including molecular biology, epidemiology, prevention, diagnosis and vaccine development. The purpose of this review is to promote ASF research and enhance its control.

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The aim of this paper is to evaluate the African swine fever (ASF) outbreak that began in 1978 in Paracambi municipality, Rio de Janeiro State, Brazil, and the steps taken by the Brazilian authorities to eradicate the disease. The presence of ASF in the country was confirmed by isolating the virus, and its pathogenicity was certified by the laboratory of the Plum Island Disease Center, New York, United States. Even before the laboratory results became available, the Brazilian Agriculture Ministry declared an Animal Health Emergency, in which the official Veterinary Services adopted rapid control measures to restrain and eradicate the disease. These control measures contributed to the reorganisation of the national swine industry and stimulated the use of high-technology production techniques, as well as an improvement in herd health consciousness. All this contributed to Brazil becoming the largest meat exporter in the world.

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The African swine fever episode in Brazil was due to trade and tourism between Spain, Portugal and Brazil, at a time when outbreaks were on the rise in Europe. The eradication of the disease, the slaughter of pigs, the elimination of the carcasses and the isolation of affected farms were given wide media coverage, and had a major socio-economic impact. It was forbidden to raise pigs in garbage dumps or to give them feed considered hazardous. Analyses performed in Brazil as well as national and international investigations by researchers from reference laboratories concluded that the disease had spread from Rio de Janeiro to other states, as is stated in official reports. Following emergency measures, a control programme was implemented, leading to enhanced quality in the pig farming sector. The authors describe epidemiological surveillance of African swine fever, classical swine fever and related diseases, biosafety in swine farming, and the emergency action plan comprising animal health training for veterinarians and social workers. The results of the eradication programme were excellent, despite the controversy over compulsory sacrifice in a country with serious social problems. In 2004, Brazil was the fourth largest pork producer and exporter, with an output of 2.679 million tons and exports of 508,000 tons to international markets with very high standards.

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