Introduction

African Swine Fever (ASF) is a devastating and economically important infectious disease of domestic and wild pigs with high mortality rate. Caused by the ASF virus (ASFV), a large double-stranded DNA virus of the Asfarviridae family, ASF is one of the diseases notifiable to the World Organization for Animal Health (Blome et al., 2020). First described in East Africa in the early 1900s, ASFV subsequently spread in the European countries and in the Caribbeans but was largely controlled in the domestic pigs by the end of 20th century (Gaudreault et al., 2020). The 21st century outbreaks of ASF in Georgia (2007), Russian Federation (2007), China (2018), India (2020), and other European and Asian countries indicate its potential emergence as a major health threat to the global pig population (Gaudreault et al., 2020; Patil et al., 2020).
Nepal is an agricultural country where livestock sector alone contributes about 11.5% of the total gross domestic product (GDP) (Poudel et al., 2020). There are about 7.3 million cattle, 5.2 million buffalos, 0.8 million sheep, 11 million goats, and 1.4 million pigs in Nepal (Poudel et al., 2020). Pig farming and pork eating are objected by religious and cultural beliefs in Nepal. However, with declining cultural bigotry, especially in the younger generation, and support and promotion of pig rearing by the Government of Nepal for poverty alleviation, pig farming is increasing in recent years (S. Dhakal et al., 2012). The total population of pig in Nepal is estimated to be around 1.4 million which is 42.30% increase from 2008/9 to 2018/19 (Figure 1) (MoALD, 2020; Poudel et al., 2020). During the same period, pork production in Nepal was increased by 68.19% with the current pork production estimation being 28,579 MT (Figure 1) (MoALD, 2020; Poudel et al., 2020). Pig meat comprises 8% of total meat production in Nepal while pork consumption is less than 1 Kg per capita out of the total national per capita meat consumption of around 11 Kg (MoALD, 2017).
Pig farming is carried out in all 77 districts of Nepal where Jhapa, a district that lies in the lowland plains (Terai) and houses about 81,000 pigs, ranks first and Mustang district, which falls in the trans-Himalayan climatic zone and has less than 100 pigs, ranks last in pig population (Figure 2) (MoALD, 2017). Pig population is higher in Province 1 in the eastern part of Nepal and in Province 5 where the pig farming ethnic communities predominate (Figure 2) (Santosh Dhakal et al., 2014).
While pig farming is growing in Nepal, diseases like ASF can jeopardize this industry which already suffers from challenges in pig breeding, marketing, feed availability, and management of other pig diseases. The recent outbreaks of ASF in Assam, India (Patil et al., 2020), which is around 670 Km away from Nepal, and in China (Ma et al., 2020), the world’s largest pig producer and Nepal’s another neighboring country, are alarming signs and big threat to Nepalese pig industry. In this scenario, this paper reviews the epidemiology of ASF in Asian countries with special emphasis on the challenges and future perspectives of ASF in Nepal.