ASF Asia: Virus likely in wild boar; floods troubling China
Vincent ter Beek, Pig Progress
Jul 24, 2020
Scientists have pointed out the likelihood that African Swine Fever is circulating unnoticed in wild boar populations in Asia. In the meantime, South Korea is gearing up for a second wave in wild boar, flooding hampers China’s restocking and Myanmar reported new outbreaks.
Timothée Vergne and Claire Guinat, 2 researchers from the National Veterinary School of Toulouse, France and Dirk U. Pfeiffer, City University of Hong Kong, sent a research letter to the journal Emerging Infectious Diseases, a publication by the Centers for Disease Control in the United States. In the letter, which was published online mid-July 2020, the authors pointed out why ASFv is likely circulating in wild boar populations in Asia.
Newly described epidemiologic cycle for ASFv
Mentioning the situation in Belgium and the Baltic states, the scientists referred to a newly described epidemiologic cycle for ASFv, suggesting that “the virus might maintain itself within wild boar populations and occasionally spill over into domestic pig farms. This newly described epidemiologic cycle proposes direct transmission among wild boar and indirect intraspecific transmission through contaminated wild boar carcasses.”
Highly suitable for wild boar
The scientists stated that maps of predicted habitat suitability suggest that most areas of East and South East Asia are highly suitable for wild boar. They wrote, “Although information is limited about the spatial distribution of wild boar in Asia, studies suggest that in some regions of China, wild boar density could be similar to that of eastern Poland.”
Substantial wild boar death
They continued, “The widespread presence of ASFv in pigs in Asia implies regular environmental spillover from the pig supply chain. Therefore, it is highly likely that ASFv is already widely circulating within some wild boar populations in Asia, causing substantial wild boar death.”
The scientists concluded: “We argue that long-term success of ASF control in Asia is possible only with risk-based ASF surveillance in wild boar populations by a multisectoral effort of wildlife and agricultural departments.”
ASF South Korea: 666 wild boar found infected
One location where plenty of information is coming from is South Korea. The Korean authorities have been meticulously reporting every wild boar carcass in the north of the country, close to the Demilitarised Zone (DMZ) at the border with North Korea. Ever since September 2019, when the virus was confirmed in the country for the first time, 666 wild boar were found in this area which tested positive for ASF. They were all found within 30 km from the border with North Korea, the vast majority in the border provinces Gyeonggi and Gangwon.
Apart from 14 pig farms found infected in September 2019, right at the beginning, no further pig farms have been found infected since October 2019. The wild boar were found mostly on the eastern half of the peninsula, but a few cases were discovered at the side of the Pacific coast.
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