Swine influenza A virus subtypes circulating in Brazilian commercial pig herds from 2012 to 2019 (original) (raw)
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Virologica Sinica, 2014
, such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and Porcine circovirus 2 (PCV2). To characterize the specific role of swine influenza virus in PRDC presentation in Colombia, 11 farms from three major production regions in Colombia were examined in this study. Nasal swabs, bronchial lavage and lung tissue samples were obtained from animals displaying symptoms compatible with SIV. Isolation of SIV was performed in 9-day embryonated chicken eggs or Madin-Darby Canine Kidney (MDCK) cells. Positive isolates, identifi ed via the hemagglutination inhibition test, were further analyzed using PCR. Overall, 7 of the 11 farms were positive for SIV. Notably, sequencing of the gene encoding the hemagglutinin (HA) protein led to grouping of strains into circulating viruses identifi ed during the human outbreak of 2009, classifi ed as pandemic H1N1-2009. Serum samples from 198 gilts and multiparous sows between 2008 and 2009 were obtained to determine antibody presence of APP, Myh, PCV2 and PRRSV in both SIV-H1N1p-negative and -positive farms, but higher levels were recorded for SIV-H1N1p-positive farms. Odds ratio (OR) and P values revealed statistically signifi cant differences (p<0.05) in PRDC presentation in gilts and multiparous sows of farms positive for SIV-H1N1p. Our fi ndings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh.
Prevalence of swine influenza virus subtypes on swine farms in the United States
Archives of Virology, 2002
Serologic and virologic prevalence of infection with different swine influenza virus (SIV) subtypes was investigated using swine sera, nasal swabs and lung samples that had been submitted for a diagnosis to the Minnesota Veterinary Diagnostic Laboratory. A total of 111,418 pig sera were tested for SIV antibody between 1998 and 2000, and 25,348 sera (22.8%) were found to be positive by the hemagglutination inhibition (HI) test. Of the positive samples, 16,807 (66.7%) and 8,541 (33.7%) had antibody to H1 and H3 subtypes, respectively. Between January 1998 and May of 2001, a total of 3,561 nasal swabs or lung samples were examined for the presence of SIV, and SIV was isolated from 1,124 samples (31.7%). Of these isolates, 869 (77.3%) and 255 (22.7%) were subtyped as H1 and H3, respectively, by the HI method. For further characterization, 120 SIV isolates each from 1998 to 2001 were randomly selected from a culture collection and their hemagglutinin (HA) and neuraminidase genes examined by reverse transcription-PCR and sequencing. Of the 480 isolates, 322 (67.1%), 22 (4.6%) and 129 (26.9%) were subtyped as H1N1, H1N2 and H3N2, respectively. The remaining 7 samples (1.5%) were found to contain both H1N1 and H3N2 viruses. The SIV H1N2 subtype was isolated from 1, 8, and 13 samples in 1999, 2000, and 2001, respectively. The 22 H1N2 isolates originated from 9 different states of the United States. Genetic screening of the HA genes of 12 selected H1N2 isolates showed that 8 of them had a close phylogenetic relationship with the Indiana isolate of H1N2 (A/Swine/Indiana/9K035/99), while 4 isolates were closely related to classical SIV H1N1.
Evidence of Swine Respiratory Infection by Influenza Viruses in Brazil
VIRUS Reviews & Research, 2006
The global surveillance of influenza, maintained by a network of laboratories sponsored by the World Health Organization, considers pigs as the host responsible for the interspecies transmission of influenza virus, particularly with regard to the transmission of avian strains to humans. This capacity was observed in 1918 when the most tragic influenza pandemic occurred as the consequence of the transmission of the avian influenza strain A(H 1 N 1 ) to humans, through pigs. This study was carried out with the aim of investigating the potential level of the influenza reservoir in Brazilian pigs. Either oronasal exudates or serum samples were collected from 34 pigs from different regions of São Paulo State, BR. These samples were evaluated by two methods: Virus isolation (passage in cell cultures) and the Hemagglutination Inhibition (HI) serological test. Results from the 34 oro-nasal samples obtained by the virus isolation method showed that all these pig exudates demonstrated the presence of influenza virus. The serological survey showed that these 34 pig sera samples presented inhibitor antibodies to different influenza virus strains with the distribution of the human influenza A subtypes (H 1 N 1 and H 3 N 2 ) and type B of 85.29% and 91.17%, respectively. These sera also presented higher percentages (97.05%) of antibodies to specific strains isolated from some of the positive pigs. These data reveal that numerous different influenza virus strains, detected in the Brazilian pig populations, were probably introduced by avians or even through humans, during swine husbandry practices.
Influenza and Other Respiratory Viruses, 2013
Background Influenza A viruses (IAV) are important pathogens responsible for economic losses in the swine industry and represent a threat to public health. In Argentina, clinical, pathological, and virological findings suggest that IAV infection is widespread among pig farms. In addition, several subtypes of IAV, such as pH1N1, H3N2, d1H1N1, and d2H1N2, have been reported.
Archives of virology, 2015
Passive monitoring for detection of influenza A viruses (IAVs) in pigs has been carried out in Brazil since 2009, detecting mostly the A(H1N1)pdm09 influenza virus. Since then, outbreaks of acute respiratory disease suggestive of influenza A virus infection have been observed frequently in Brazilian pig herds. During a 2010-2011 influenza monitoring, a novel H1N2 influenza virus was detected in nursery pigs showing respiratory signs. The pathologic changes were cranioventral acute necrotizing bronchiolitis to subacute proliferative and purulent bronchointerstitial pneumonia. Lung tissue samples were positive for both influenza A virus and A(H1N1)pdm09 influenza virus based on RT-qPCR of the matrix gene. Two IAVs were isolated in SPF chicken eggs. HI analysis of both swine H1N2 influenza viruses showed reactivity to the H1d cluster. DNA sequencing was performed for all eight viral gene segments of two virus isolates. According to the phylogenetic analysis, the HA and NA genes clustered with influenza viruses of the human lineage (H1-d cluster, N2), whereas the six internal gene segments clustered with the A(H1N1)pdm09 group. This is the first report of a reassortant human-like H1N2 influenza virus derived from pandemic H1N1 virus causing an outbreak of respiratory disease in pigs in Brazil. The emergence of a reassortant IAV demands the close monitoring of pigs through the fullgenome sequencing of virus isolates in order to enhance genetic information about IAVs circulating in pigs.
Molecular evaluation of influenza A virus in swine at slaughterhouses in Colombia
23(Supl), 2018
Objective. To assess the presence of influenza A virus and to evaluate the impact of the 2009 pandemic H1N1 influenza virus on the endemic strains circulating in the Colombian swine population after its emergence and spread. Materials and methods. 369 lung tissue samples were collected from clinically normal slaughterhouse pigs from 11 geographic regions of Colombia, which were analyzed using qRT-PCR test for the detection of influenza A virus. After molecular detection, positive samples were processed to perform isolation trials in specific pathogen free chicken embryo eggs, and the presence of the virus was accomplished by hemagglutination test and RT-PCR assays. Results. Molecular detection techniques showed circulation of swine influenza viruses in five out of 11 geographic regions monitored. Likewise, sample testing by viral isolation analysis enabled successful recovery and confirmation of five viral strains from two geographic regions. Conclusions. It was possible to demonstrate that slaughterhouses represent a feasible alternative for research and characterization of influenza virus, allowing researchers to collect pig samples from different origins. They also provide a useful tool for achieving viral isolation and early detection of molecular changes that would help to anticipate the appearance of strains with pandemic and/or epidemic potential throughout the national territory.