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Clin Infect Dis. 2019 Sep 1. pii: ciz865. doi: 10.1093/cid/ciz865. [Epub ahead of print]
High Risk of Influenza Virus Infection Among Swine Workers: Examining a Dynamic Cohort in China.
Borkenhagen LK1, Wang GL2, Simmons RA1, Bi ZQ3,4, Lu B5, Wang XJ3,4, Wang CX6, Chen SH5, Song SX3,4, Li M6, Zhao T2, Wu MN2, Park LP1, Cao WC2, Ma MJ2, Gray GC1,7,8.
Author information
1 Division of Infectious Diseases, School of Medicine, Global Health Institute, Duke University, Durham, North Carolina, USA. 2 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China. 3 Shandong Provincial Center for Disease Control and Prevention, Jinan, China. 4 Shandong Provincial Key Laboratory of Disease Control and Prevention, Jinan, China. 5 Wuxi Center for Disease Control and Prevention, Wuxi, China. 6 Licheng District Center for Disease Control and Prevention, Jinan, China. 7 Global Health Research Center, Duke Kunshan University, Kunshan, China. 8 Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore.
Abstract
BACKGROUND:
China is thought to be a hotspot for zoonotic influenza virus emergence, yet there have been few prospective studies examining the occupational risk of such infections.
METHODS:
We present the first two years of data collected from a five-year, prospective cohort study of swine-exposed and unexposed participants, pigs, and six swine farms in China. We conducted serological and virological surveillance to examine evidence for swine influenza A virus infection in humans.
RESULTS:
Two hundred and seven (31.5%) of the 658 participants (521 swine-exposed and 137 unexposed), enrolled at any time period, seroconverted against at least one SIV subtype (swine H1N1 or H3N2). Swine-exposed participants' microneutralization titers, especially those enrolled at confined animal feeding operations (CAFOs), were higher against the swine H1N1 virus than were other participants at 12 and 24 months. Despite elevated titers, among the 187 study subjects for whom we had complete follow-up, participants working at swine CAFOs had significantly greater odds of seroconverting against both swine H1N1 (OR 19.16; 95% CI 3.55, 358.65) and swine H3N2 (OR 2.97; 95% CI 1.16, 8.01) viruses compared to unexposed and non-CAFO swine workers with less intense swine exposure.
CONCLUSIONS:
While some of the observed increased risk against swine viruses may have been explained by exposure to human influenza strains, study data suggest that even with elevated preexisting antibodies, swine-exposed workers are at high risk of infection with enzootic swine influenza A viruses.
? The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
KEYWORDS:
epidemiology; influenza A virus; swine influenza; zoonoses
PMID: 31504322 DOI: 10.1093/cid/ciz865
High Risk of Influenza Virus Infection Among Swine Workers: Examining a Dynamic Cohort in China.
Borkenhagen LK1, Wang GL2, Simmons RA1, Bi ZQ3,4, Lu B5, Wang XJ3,4, Wang CX6, Chen SH5, Song SX3,4, Li M6, Zhao T2, Wu MN2, Park LP1, Cao WC2, Ma MJ2, Gray GC1,7,8.
Author information
1 Division of Infectious Diseases, School of Medicine, Global Health Institute, Duke University, Durham, North Carolina, USA. 2 State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China. 3 Shandong Provincial Center for Disease Control and Prevention, Jinan, China. 4 Shandong Provincial Key Laboratory of Disease Control and Prevention, Jinan, China. 5 Wuxi Center for Disease Control and Prevention, Wuxi, China. 6 Licheng District Center for Disease Control and Prevention, Jinan, China. 7 Global Health Research Center, Duke Kunshan University, Kunshan, China. 8 Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore.
Abstract
BACKGROUND:
China is thought to be a hotspot for zoonotic influenza virus emergence, yet there have been few prospective studies examining the occupational risk of such infections.
METHODS:
We present the first two years of data collected from a five-year, prospective cohort study of swine-exposed and unexposed participants, pigs, and six swine farms in China. We conducted serological and virological surveillance to examine evidence for swine influenza A virus infection in humans.
RESULTS:
Two hundred and seven (31.5%) of the 658 participants (521 swine-exposed and 137 unexposed), enrolled at any time period, seroconverted against at least one SIV subtype (swine H1N1 or H3N2). Swine-exposed participants' microneutralization titers, especially those enrolled at confined animal feeding operations (CAFOs), were higher against the swine H1N1 virus than were other participants at 12 and 24 months. Despite elevated titers, among the 187 study subjects for whom we had complete follow-up, participants working at swine CAFOs had significantly greater odds of seroconverting against both swine H1N1 (OR 19.16; 95% CI 3.55, 358.65) and swine H3N2 (OR 2.97; 95% CI 1.16, 8.01) viruses compared to unexposed and non-CAFO swine workers with less intense swine exposure.
CONCLUSIONS:
While some of the observed increased risk against swine viruses may have been explained by exposure to human influenza strains, study data suggest that even with elevated preexisting antibodies, swine-exposed workers are at high risk of infection with enzootic swine influenza A viruses.
? The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
KEYWORDS:
epidemiology; influenza A virus; swine influenza; zoonoses
PMID: 31504322 DOI: 10.1093/cid/ciz865