Slaughterhouse Surveillance for Subclinical Foot-and-Mouth Disease Virus in Vietnam

Authors: GUNASEKARA, UMANGA - University Of Minnesota; Bertram, Miranda; VANNATTA, TREVOR - Dept Of Animal Health, Vietnam; DUNG, DO - Dept Of Animal Health, Vietnam; HOANG, BUI - Dept Of Animal Health, Vietnam; VU, LE - Dept Of Animal Health, Vietnam; DONG, PHAM - Dept Of Animal Health, Vietnam; PEREZ, ANDRES - University Of Minnesota; VANDERWAAL, KIMBERLY - University Of Minnesota; Arzt, Jonathan; PHUONG, NGUYEN - Dept Of Animal Health, Vietnam; HUNG, VO - Dept Of Animal Health, Vietnam; LONG, NGUYEN - Dept Of Animal Health, Vietnam; PHAN, MINH - Dept Of Animal Health, Vietnam

Submitted to: Global Foot-and Mouth Disease Research Alliance (GFRA)
Publication Type: Proceedings
Publication Acceptance Date: 10/29/2021
Publication Date: N/A
Citation: N/A
DOI: https://doi.org/10.3390/v13112203

Interpretive Summary: Foot-and-mouth disease (FMD) is an economically important livestock disease worldwide. Surveillance is important for early detection and control of outbreaks, however surveillance can be expensive and logistically challenging in many parts of the world. In this study, cattle and buffalo were sampled at slaughterhouses in Vietnam to determine whether slaughterhouses can serve as surveillance points for FMD. FMD viruses were sequenced from samples collected from slaughterhouses and from sick animals during FMD outbreaks. Virus strains detected in outbreak samples were also detected in slaughterhouse samples, suggesting slaughterhouses could be cost-effective points of surveillance.

Technical Abstract: The objective of this study was to evaluate sampling of clinically healthy livestock at slaughterhouses as a strategy for genomic FMDV surveillance. In two slaughterhouses in southern Vietnam, 1200 serum and OPF samples were collected from asymptomatic cattle and buffalo (2017 to 2019) as a pilot study on the use of slaughterhouses as sentinel points of surveillance. FMDV VP1 sequences were analyzed using discriminant principal component analysis (DAPC) and time-scaled phylodynamic trees. Delineation of different clusters enabled tabulation of when and where distinct FMDV variants were detected. Viruses isolated from slaughterhouses clustered together with viruses recovered from farms during the same period, indicating that slaughterhouses are representative of FMDV circulation at the farm level. Six of seven serotype O and A clusters circulating in southern Vietnam from 2017-19 were detected at least once in slaughterhouses, sometimes pre-dating outbreak sequences associated with the same cluster by 4-6 months.