Detection of foot-and-mouth disease (FMD) virus in healthy cattle and buffalo at Southeast Asian slaughterhouses

Authors: BUCKLE, KELLY - Ministry For Primary Industries; BUENO, RUDOLFO - Ministry For Primary Industries; MCFADDEN, ANDREW - Ministry For Primary Industries; VAN ANDEL, MARY - Ministry For Primary Industries; SPENCE, RICHARD - Ministry For Primary Industries; ABILA, RONEL - World Organization For Animal Health; VERIN, BLESILDA - World Organization For Animal Health; KHOUNSEY, SYSENG - Ministry Of Agriculture And Forestry; LUDI, ANNA - The Pirbright Institute; Arzt, Jonathan

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2021
Publication Date: 7/23/2021
Citation: Buckle, K., Bueno, R., Mcfadden, A., Van Andel, M., Spence, R., Abila, R., Verin, B., Khounsey, S., Ludi, A., Arzt, J. 2021. Detection of foot-and-mouth disease (FMD) virus in healthy cattle and buffalo at Southeast Asian slaughterhouses. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2021.691308.
DOI: https://doi.org/10.3389/fvets.2021.691308

Interpretive Summary: Foot-and-mouth disease (FMD) is an important viral disease affecting animal health and economics through impacts on agriculture and trade. The disease is caused by foot-and-mouth disease virus (FMDV) which is widespread throughout much of the world, including parts of South East Asia. The purpose of the current study was to determine if FMDV could be detected in healthy cattle and buffalo in slaughterhouses in Laos and Myanmar. This is important because surveying for the virus in slaughterhouses is much more efficient than going out to field locations. The critical findings of the paper are that 7.3% of animals had the virus in their tissues and 37.8% of animals had evidence of previous infection based on antibodies in blood. This information is important to US agriculture because it affects the regulation of trade in Asia and globally.

Technical Abstract: Foot-and-mouth disease virus (FMDV) is widespread throughout much of the world, including parts of South East Asia. As part of the World Organisation for Animal Health (OIE)’s South East Asia and China Foot-and-Mouth Disease Project (SEACFMD), field sampling was performed to help understand evidence of widespread virus exposure observed previously. Serum and dry mucosal swabs were collected to evaluate the presence of FMDV RNA on the nasal, oral, and dorsal nasopharyngeal mucosal surfaces of 262 healthy cattle (n=38 in Laos; n=47 in Myanmar) and buffalo (n=12 in Laos; n=2 in Myanmar) immediately following slaughter in three slaughterhouses. Swabs and serum were tested by the OIE FMD world reference laboratory using pan-serotypic real-time reverse transcription-PCR (RT-PCR) and serum was evaluated using the FMD PrioCHECK non-structural protein (NSP) ELISA. In total, 7.3% of animals had detectable FMDV RNA in one or more of the three sites including 5.3% of nasopharyngeal swabs, 2.3% of oral swabs, and 1.5% of nasal swabs. In all animals, serum was found not to contain detectable FMDV RNA, and 37.8% of animals were positive for NSP antibodies, indicating likely past exposure to FMDV. Results were comparable for Laos and Myanmar, and were similar for both cattle and buffalo. The current study demonstrates the utility of detection by swabbing the nasopharynx in the post-mortem context, in situations such as post-mortem where probang samples are not feasible. Additionally, FMDV present on the oral and nasal mucosa of clinically-healthy large ruminants in Laos and Myanmar, if viable, may potentially play a role in the epidemiology of FMD in these countries, and perhaps more widely within Southeast Asia.