tetano
Editor, Senior Moderator
Authors: Karen Trevennec,a,b Lucas Leger,a Faouzi Lyazrhi,b Eug?nie Baudon,c Chung Yan
Cheung,d Fran?ois Roger,a J.S. Malik Peiris,c,d Jean-Michel Garciac
Authors affiliations:
a French Agricultural Research Center for International Development (CIRAD), Animal and
Integrated Risk Management Research Unit (AGIRs), Montpellier, France;
b Ecole National V?t?rinaire de Toulouse (ENVT), INP, Toulouse, France;
c HKU-Pasteur Research Centre, Hong Kong Special Administrative Region, People's
Republic of China;
d Department of Microbiology, The University of Hong Kong, Hong Kong Special
Administrative Region, People's Republic of China.
Address for correspondence: Karen Trevennec, French Agricultural Research Center for
International Development (CIRAD), Animal and Integrated Risk Management Research
Unit, Baillarguet Campus, 34398 Montpellier Cedex 5, France. Phone: +33 4 67 59 39 53
Fax: +33 4 67 59 37 54 email: carlene.trevennec@cirad.fr
Abstract: 246 words
Text: 4929 words
Abstract
Background: The pandemic of 2009 was caused by an H1N1 (H1N1pdm) virus of swineorigin.
This pandemic virus has repeatedly infected swine through reverse zoonosis although the extent of such infection in swine remains unclear.
Objective: This study targets small and commercial pig producers in North Vietnam, in order to estimate the extent of H1N1pdm infection in swine and to identify risk factors of infection.
Methods: Virologic and serologic surveillance of swine was carried out in 2009-2010 in pig farms (38 swabs and 1732 sera) and at a pig slaughterhouse (710 swabs and 459 sera) in North Vietnam. The sera were screened using a influenza type A reactive ELISA assay and
positive sera were tested using haemagglutination inhibition tests for antibody to a panel of H1-subtype viruses representing pandemic (H1N1) 2009 (H1N1pdm), triple reassortant (TRIG), classical swine (CS) and Eurasian avian-like (EA) swine lineages. Farm-level risk factors were identified using a zero-inflated negative binomial model.
Results: We found a maximal seroprevalence of H1N1pdm of 55.6% [95% CI: 38.1 - 72.1] in the slaughterhouse at the end of December 2009, two weeks after the peak of reported human fatalities with H1N1pdm. Farm-level seroprevalence was 29% [95% CI: 23.2-35.7]. In
seropositive farms, within-herd seroprevalence ranged from 10-100%. We identified an increased risk of infection for farms that specialized in fattening and a decreased risk of infection in farms hiring external swine workers.
Conclusions: Our findings suggest extensive reverse-zoonotic transmission from humans to pigs with subsequent onward transmission within pig-herds.
http://www.google.com/url?sa=t&rct=...sg=AFQjCNEBBXM-grvUPnVNE36rtp7xdgXyVA&cad=rja
Cheung,d Fran?ois Roger,a J.S. Malik Peiris,c,d Jean-Michel Garciac
Authors affiliations:
a French Agricultural Research Center for International Development (CIRAD), Animal and
Integrated Risk Management Research Unit (AGIRs), Montpellier, France;
b Ecole National V?t?rinaire de Toulouse (ENVT), INP, Toulouse, France;
c HKU-Pasteur Research Centre, Hong Kong Special Administrative Region, People's
Republic of China;
d Department of Microbiology, The University of Hong Kong, Hong Kong Special
Administrative Region, People's Republic of China.
Address for correspondence: Karen Trevennec, French Agricultural Research Center for
International Development (CIRAD), Animal and Integrated Risk Management Research
Unit, Baillarguet Campus, 34398 Montpellier Cedex 5, France. Phone: +33 4 67 59 39 53
Fax: +33 4 67 59 37 54 email: carlene.trevennec@cirad.fr
Abstract: 246 words
Text: 4929 words
Abstract
Background: The pandemic of 2009 was caused by an H1N1 (H1N1pdm) virus of swineorigin.
This pandemic virus has repeatedly infected swine through reverse zoonosis although the extent of such infection in swine remains unclear.
Objective: This study targets small and commercial pig producers in North Vietnam, in order to estimate the extent of H1N1pdm infection in swine and to identify risk factors of infection.
Methods: Virologic and serologic surveillance of swine was carried out in 2009-2010 in pig farms (38 swabs and 1732 sera) and at a pig slaughterhouse (710 swabs and 459 sera) in North Vietnam. The sera were screened using a influenza type A reactive ELISA assay and
positive sera were tested using haemagglutination inhibition tests for antibody to a panel of H1-subtype viruses representing pandemic (H1N1) 2009 (H1N1pdm), triple reassortant (TRIG), classical swine (CS) and Eurasian avian-like (EA) swine lineages. Farm-level risk factors were identified using a zero-inflated negative binomial model.
Results: We found a maximal seroprevalence of H1N1pdm of 55.6% [95% CI: 38.1 - 72.1] in the slaughterhouse at the end of December 2009, two weeks after the peak of reported human fatalities with H1N1pdm. Farm-level seroprevalence was 29% [95% CI: 23.2-35.7]. In
seropositive farms, within-herd seroprevalence ranged from 10-100%. We identified an increased risk of infection for farms that specialized in fattening and a decreased risk of infection in farms hiring external swine workers.
Conclusions: Our findings suggest extensive reverse-zoonotic transmission from humans to pigs with subsequent onward transmission within pig-herds.
http://www.google.com/url?sa=t&rct=...sg=AFQjCNEBBXM-grvUPnVNE36rtp7xdgXyVA&cad=rja