Dataset Information

Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs.

ABSTRACT: Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The current study describes the clinical epidemiology, pathology, and molecular and biological characteristics of the virus. Phylogenetic analysis revealed that the virus isolate shared nucleotide identities of 96-98?% with H3N2 IAVs that circulated in humans from 2000 to 2003. Antigenically, sera from experimentally inoculated animals cross-reacted mainly with non-contemporary human-origin H3N2 influenza viruses. In an experimental infection in a commercial swine breed, the virus was of low virulence but was transmitted efficiently to contact pigs and caused severe disease when an infected animal acquired a secondary bacterial infection. This is the first report of a wholly human H3N2 IAV associated with clinical disease in pigs in South America. These studies highlight the importance of two-way transmission of IAVs and SIVs between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide.

SUBMITTER: Cappuccio JA

PROVIDER: S-EPMC3352566 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs.

Cappuccio Javier A JA Pena Lindomar L Dibárbora Marina M Rimondi Agustina A Piñeyro Pablo P Insarralde Lucas L Quiroga María A MA Machuca Mariana M Craig Maria I MI Olivera Valeria V Chockalingam Ashok A Perfumo Carlos J CJ Perez Daniel R DR Pereda Ariel A

The Journal of general virology 20110817 Pt 12

Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The curren ...[more]

PMID: 21849519

Similar Datasets

Project description:Virus strains in the live attenuated influenza vaccine (LAIV) for swine in the United States that was on the market until 2020 encode a truncated nonstructural protein 1 of 126 amino acids (NS1del126). Their attenuation is believed to be due to an impaired ability to counteract the type I interferon (IFN)-mediated antiviral host response. However, this mechanism has been documented only in vitro for H3N2 strain A/swine/Texas/4199-2/98 NS1del126 (lvTX98), and several cases of clinical respiratory disease in the field were associated with the LAIV strains. We therefore further examined the pathobiology, including type I IFN induction, of lvTX98 in pigs and compared it with IFN induction in pig kidney-15 (PK-15) cells. lvTX98 induced up to 3-fold-higher type I IFN titers than wild-type TX98 (wtTX98) after inoculation of PK-15 cells at a high multiplicity of infection, while virus replication kinetics were similar. Mean nasal lvTX98 excretion by intranasally inoculated pigs was on average 50 times lower than that for wtTX98 but still reached titers of up to 4.3 log10 50% tissue culture infective doses/mL. After intratracheal inoculation, mean lvTX98 titers in the lower respiratory tract were significantly reduced at 18 to 48 h postinoculation (hpi) but similar to wtTX98 titers at 72 hpi. lvTX98 caused milder clinical signs than wtTX98 but induced comparable levels of microscopic and macroscopic lung lesions, peak neutrophil infiltration, and peak type I IFN. Thus, lvTX98 was partly attenuated in pigs, but this could not be associated with higher type I IFN levels. IMPORTANCE Swine influenza A viruses (swIAVs) with a truncated NS1del126 protein were strongly attenuated in previous laboratory-based safety studies and therefore approved for use as LAIVs for swine in the United States. In the field, however, the LAIV strains were detected in diagnostic samples and could regain a wild-type NS1 via reassortment with endemic swIAVs. This suggests a significant degree of LAIV replication and urges further investigation of the level and mechanism of attenuation of these LAIV strains in vivo. Here, we show that H3N2 LAIV strain lvTX98 is only partly attenuated in pigs and is excreted at significant titers after intranasal vaccination. Attenuation and restricted replication of lvTX98 in vivo seemed to be associated with the loss of NS1 functions other than type I IFN antagonism. Our findings can help to explain the occurrence of clinical respiratory disease and reassortment events associated with NS1del126-based LAIV strains in the field.

Dataset Information

Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs.

Publications

Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets