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 Peoples 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 9 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.