The impact of African swine fever virus on smallholder village pig production: An outbreak investigation in Lao PDR

Abstract

African swine fever virus (ASFV) causes a deadly disease of pigs which spread through southeast Asia in 2019. We investigated one of the first outbreaks of ASFV in Lao People's Democratic Republic amongst smallholder villages of Thapangtong District, Savannakhet Province. In this study, two ASFV affected villages were compared to two unaffected villages. Evidence of ASFV‐like clinical signs appeared in pig herds as early as May 2019, with median epidemic days on 1 and 18 June in the two villages, respectively. Using participatory epidemiology mapping techniques, we found statistically significant spatial clustering in both outbreaks (p < 0.001). Villagers reported known risk factors for ASFV transmission – such as free‐ranging management systems and wild boar access – in all four villages. The villagers reported increased pig trader activity from Vietnam before the outbreaks; however, the survey did not determine a single outbreak source. The outbreak caused substantial household financial losses with an average of nine pigs lost to the disease, and Monte Carlo analysis estimated this to be USD 215 per household. ASFV poses a significant threat to food and financial security in smallholder communities such as Thapangtong, where 40.6% of the district's population are affected by poverty. This study shows ASFV management in the region will require increased local government resources, knowledge of informal trader activity and wild boar monitoring alongside education and support to address intra‐village risk factors such as free‐ranging, incorrect waste disposal and swill feeding.

Beyond Numbers: Determining the Socioeconomic and Livelihood Impacts of African Swine Fever and Its Control in the Philippines

“…This is important because the spread of ASF among smallholder communities in Southeast Asia and the Pacific is superimposed over a complex vulnerability context. Seasonal adverse weather events and corresponding pig disease outbreaks as described in this study are also experienced in other countries inflicted with the disease (26,32) and these events are only expected to increase with climate change (33). Further, the seasonal peaks and troughs in demand for pork coinciding with ceremonies and cultural events in the Philippines are also seen in other affected countries (32,34,35).…”

“…All farmers in this study, from small and larger properties experienced financial losses from the ASF epidemic. The financial impacts of ASF on farmers have been described in detail in Africa (19)(20)(21)(22)(23); reviewed in (24) and Asia (25,26). The negative impacts on broader pig value chain players have been described but not quantified in Cameroon (27) and Tanzania (28).…”

African Swine Fever, the forgotten pandemic

“…The financial impact can be substantial. For example, Matsumoto et al (2021) studied the first outbreaks of ASF in Lao Peoples Democratic Republic amongst smallholder villages in a district where 40% of the population are affected by poverty. On average, households lost nine pigs during the outbreak, costing an estimated USD 215 per household.…”

Partitioning, a Novel Approach to Mitigate the Risk and Impact of African Swine Fever in Affected Areas

“…For example, certain countries report ASF outbreaks in wildlife as "individual animals affected by the disease" (37,38), whereas other countries refer to outbreaks in wildlife as "regions" in which the disease was identified (39,40). Also, in countries with extensive backyard farming where free-range pigs coexist, the village or commune is considered the epidemiological unit (41)(42)(43), whereas in industrial swine production that definition is typically applied to the farm (15). Therefore, the definition of epidemiological unit to enforce outbreak control measures is flexible and linked to the concept of subpopulations' exposure and disease risk.…”