An epidemiological study of prevalence among swine at industrial swine farms in Northern Vietnam.

INTRODUCTION

is a zoonotic pathogen found in swine that may cause systemic infection in humans. is endemic in Southeast Asia and is the leading cause of adult meningitis in Vietnam. Given Vietnam's increasing centralization of the swine industry, we sought to estimate the prevalence of on large swine farms in Northern Vietnam.

METHODS

A cross-sectional, one-health-oriented, surveillance study for was conducted between October 2019-March 2020. Swine oral, swine worker nasal, and bioaerosol samples were collected from four large-scale swine farms (>500 swine) in three provinces in Northern Vietnam: Lao Cai, Bac Giang, and Quang Ninh. Samples were evaluated for presence of growth on blood agar plates and confirmed with conventional polymerase chain reaction.

RESULTS

The authors found that 4/174 (2.3%, 95% CI: 0.6-5.8%) of swine oral samples and 1/58 (1.7%, 95% CI: 0-9.2%) bioaerosol samples were positive for by bacterial culture and conventional PCR. was not detected in any swine worker nasal wash samples. There was no significant relationship between sampling location and month of sample collection with results of swine oral or bioaerosol samples.

CONCLUSION

Compared to previous reports from slaughterhouses in Vietnam, the lower than expected prevalence of supports the notion that that recent efforts to centralize Vietnam's pork industry through establishment of large-scale farms with better biosecurity may have been effective in limiting prevalence on these large farms.