Factors Contributing to the Spread of ASF in Asia
Four of the top 10 pork producing countries in the world, namely China,
Vietnam, Philippines, and South Korea produce 34,000; 2,250; 1,450 and
1,350 thousand Metric Ton respectively, are in Asia (Statista, 2020).
Historically Asian countries were less affected with ASF which may be
attributed to the effective sanitary regulation and strict rules for
import of animals and animal products (Costard et al., 2013). Periodic
outbreak of various viral and prion diseases including BSE, Avian
influenza, Classical swine fever has further alerted various Asian
countries to strengthen veterinary services (Ozawa et al., 2006).
Recently, outbreaks of ASF are reported in Asian countries including
China, Laos, Vietnam, India and is rapidly spreading all over Asia
(Table 3) (OIE, 2021). China is the key Asian country for the production
and supply of pork globally. There is high risk for the entry of ASF
into various other Asian countries through China as it has international
trade with various countries of Africa where ASF outbreak have been
recently reported (Costard et al., 2013). Furthermore, various cultural
events in Asia demand more pork supply that increases the risk of ASFV
transmission and ASF outbreaks. Illegal import of pig products also
favors the entry and outbreak of disease vigorously (Shih et al., 2005).
Movement of live animal and pig products support the condition for
spread of the virus at the regional level. Most of the Asian countries
practice free ranging pig husbandry system that causes endemic outbreak
of ASF. Beside this, existence of wild pigs also favors the potential
outbreak of disease since the virus is maintained in wild suid
reservoirs. Study of soft tick includingOrnithodoros (Alectorobius ) spp. is also due essential to
better understand the dynamic of spread of disease by these vectors in
Asian territories (Ahmed et al., 2007).