Pre-Pandemic Viral Surveillance of Swine Farms in Northern Vietnam

Abstract

Introduction: Global pandemics are major contributors to human morbidity and mortality, economic downturn, and lost productivity. In extraordinary circumstances like the COVID-19 pandemic, we see a showcase of these staggering costs. It has been proposed that surveillance for zoonotic infectious diseases will be integral for limiting the next pandemic. In this pilot project, we employ a group of molecular assays to study bioaerosol samples for evidence of viruses that might pose a zoonotic threat.Methods: Bioaerosol samples and swine farm characteristics were collected from eight farms in Northern Vietnam during the years of 2019 to 2021. We evaluated 256 specimens using conventional PCR/RT-PCR pan-species coronaviridae and paramyxoviridae molecular assays for evidence of viral presence. Amplicons that appeared to represent a targeted virus family were subsequently sent for sequencing and characterized.Results: The farms surveyed had an average temperature of 26.3oC and relative humidity of 65.0%. Among the 256 bioaerosol samples studied, 2 showed molecular evidence for paramyxoviruses (0.78%) and none were positive for coronaviruses. Sequencing attempts of the positive samples confirmed evidence of paramyxovirus presence.Conclusions: Compared to previous publications of viral presence on swine farms, the rates in our study were slightly lower than expected. This might suggest that the swine farms surveyed in this experiment had fewer circulating viruses than typically seen. Despite this, our work suggests that molecular studies of bioaerosol samples can be used to non-invasively screen for novel zoonotic pathogens within swine farm facilities.