Spatiotemporal distribution of highly pathogenic avian influenza subtype
H5N8 in Korea
Abstract
In zoonotic disease, highly pathogenic avian influenza (HPAI) is a major
threat to human and poultry health worldwide. In January 2014, HPAI
virus subtype H5N8 first infected poultry farms in South Korea, and a
total of 393 outbreaks were reported with enormous economic damage in
the poultry industry. We analyzed the spatiotemporal distribution of
HPAI H5N8 outbreaks in poultry farms using the global and local
spatiotemporal interactions in the first outbreak wave from January 2014
to June 2015 and the second wave from September 2014 to June 2015. The
space-time K-function analyses revealed significant interactions within
three days and over 40 km in two study periods in global spatiotemporal
interaction. The excess risk attributable value (D0) was maintained
despite the distance in the case of HPAI H5N8 in Korea. Eleven
spatiotemporal clusters were identified, and the results show the HPAI
introduction from the southwestern region and the spread to the middle
region in Korea. Six clusters were distributed in 0.46-9.86 km space and
3-19 days in time, while five clusters were distributed in 19.74-72.59
km space and 27-36 days in time. This global and local spatiotemporal
interaction indicates that the HPAI epidemic in Korea was mostly
characterized by short period transmission within a small area and
dispersed by long-range jumps. This finding supports strict control
strategies such as preemptive depopulation, the standstill, and poultry
movement tracking. More studies are needed to understand HPAI disease
transmission patterns of HPAI in Korea.