Studies of H5N1 influenza virus infection of pigs by using viruses isolated in Vietnam and Thailand in 2004.
To determine whether avian H5N1 influenza viruses associated with human infections in Vietnam had transmitted to pigs, we investigated serologic evidence of exposure to H5N1 influenza virus in Vietnamese pigs in 2004. Of the 3,175 pig sera tested, 8 (0.25%) were positive for avian H5N1 influenza viruses isolated in 2004 by virus neutralization assay and Western blot analysis. Experimental studies of replication and transmissibility of the 2004 Asian H5N1 viruses in pigs revealed that all viruses tested replicated in the swine respiratory tract but none were transmitted to contact pigs. Virus titers from nasal swabs peaked on day 2, and low titers were detected in the liver of two of the four pigs tested. Our findings indicate that pigs can be infected with highly lethal Asian H5N1 viruses but that these viruses are not readily transmitted between pigs under experimental conditions.
Choi
Young Ki
YK
Division of Virology, Department of Infectious Diseases, Mail Stop 330, St. Jude Children's Research Hospital, 332 N. Lauderdale St., Memphis, TN 38105-2794, USA.
Nguyen
Tien Dzung
TD
Ozaki
Hiroichi
H
Webby
Richard J
RJ
Puthavathana
Pilaipan
P
Buranathal
Chantanee
C
Chaisingh
Arunee
A
Auewarakul
Prasert
P
Hanh
N T H
NT
Ma
Sia Kit
SK
Hui
Pui Yan
PY
Guan
Yi
Y
Peiris
Joseph Sriyal Malik
JS
Webster
Robert G
RG
D000818:Animals; D053124:Influenza A Virus, H5N1 Subtype; D009980:Influenza A virus / Q000302:isolation & purification*; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000635:transmission / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000473:pathology / Q000821:virology*