African Swine Fever Virus (ASFV) is a highly contagious pathogen causing
disease in pigs, commonly characterised by acute haemorrhagic fever.
Prior to August 2018, African Swine Fever (ASF) had not been reported in
Asia, but has since spread throughout China, Mongolia, Korea, Vietnam,
Laos, Cambodia, Myanmar, the Philippines, Hong Kong, Indonesia,
Timor-Leste and Papua New Guinea. Using data collated from reports of
confirmed cases, we applied spatio-temporal analysis to describe ASFV
spread throughout Asia, from 1 August 2018 (reported start date) to 31
December 2019. Analysis revealed a propagating epidemic of ASFV
throughout Asia, with peaks corresponding to increased reports from
China, Vietnam and Laos. Two clusters of reported outbreaks were found.
During the epidemic, ASFV primarily spread from the North-East to the
South-East: a larger, secondary cluster in the North-East represented
earlier reports, whilst the smaller, primary cluster in the South-East
was characterised by later reports. Significant differences in
country-specific epidemics, morbidity, mortality and unit types were
discovered, likely attributable to differences in prevention,
surveillance and control measures. The initial number of outbreaks and
enterprise size are likely predictors of the speed of spread and the
effectiveness of ASFV stamping out procedures. Biosecurity methods, wild
boar populations and the transportation of pigs and movement of infected
fomites are discussed as likely risk factors for facilitating ASFV
spread across Asia.
African Swine Fever spread across Asia, 2018---2019