The Role of the Wild Boar Spreading African Swine Fever Virus in Asia: Another Underestimated Problem

Abstract

African swine fever (ASF) is a highly lethal infectious disease in naive populations of domestic pigs and wild boar. In Asia, from the first outbreak in August 2018 until the end of November 2021, ASF has been reported in 16 Asian countries. The ASF virus (ASFV) circulation in domestic pigs is considered the main problem in Asia. On the other hand, there are very few reports of ASF in wild boar in this region. However, considering the high wild boar density within the same area of smallholder domestic pig farms in Asia, the occurrence of ASFV infection in wild boar may be underestimated. The role of the wild boar in other ASF epidemiological scenarios, such as Europe, is a key for the maintenance and transmission of the disease. Hence, we performed a preliminary study estimating the extent of ASFV infection in the Asian wild boar population. The potential risk area of ASF-infected wild boar was calculated based on the habitat suitability for wild boar, the kernel density of ASF notification in smallholder farms and wild boar, and the ASFV transmission rate of wild boar. As a result of the analysis, high-, medium-, and low-risk areas were identified throughout Southeast and East Asia. The highest risk area was detected in China, followed by Myanmar, Far East Russia, Thailand, Vietnam, Laos, Cambodia, and the Philippines. Additionally, another risk area was detected from northeastern China to the Korean Peninsula, including Far East Russia. This study shows hot spots where a high risk of infection in wild boar is most likely to occur, helping to control ASF.

Landscape connectivity for predicting the spread of ASF in the European wild boar population

“…The applicability of this tool into other regions of the world, such as Asia where the disease is rapidly spreading and there is limited information on the affected wild boar populations 31 , could improve the understanding of ASF dispersion there. However, before being applied to other continents, it is important to adapt the connectivity models to address the specific relationships of the species with different landscapes.…”

Landscape connectivity for predicting the spread of ASF in the European wild boar population

“…However, only with the combination of this tool with other available management plans, the holistic approach needed to fully tackle the problematic control of the disease could be signi cantly improved. In that sense, the inclusion of epidemiological models for both wild boar and domestic pigs, such as transmission dynamics 7 , wild boar -domestic pig interface 11,38 , as well as risk of exposure assessment analyses [39][40][41] would be highly bene cial to improve control and prevention strategies. Other transmission routes, apart from the natural spread of the disease in wild boar studied here, should be considered for such ASF plans 42 .…”

“…The applicability of this tool into other regions of the world, such as Asia where the disease is rapidly spreading and there is limited information on the affected wild boar populations 40 , could improve the understanding of ASF dispersion there. However, before being applied to other continents, it is important to adapt the connectivity models to address the speci c relationships of the species with different landscapes.…”

Development and Immunological Evaluation of a Multiantigen Thermostable Nanovaccine Adjuvanted with T-Cell-Activating Scaffold for African Swine Fever

“…In 2007, ASFV genotype II emerged in Georgia and continued to spread to more countries . The spread of ASF continues with outbreaks in Southeast Asia, including Thailand, the Philippines, and other countries. − Because no effective ASF vaccine is available, the prevention and control of ASF are primarily at the level of biosecurity, employing multiple lines of defense that block the spread of ASF . These approaches are less than optimal, and improvements in infection prevention and control and the development of an ASF vaccine are essential.…”