[Show abstract][Hide abstract] ABSTRACT: In January 2012, several clinical cases of dogs with flu-like symptoms, including coughing, sneezing, nasal discharge, and fever, were reported in a small-animal hospital located in Bangkok, Thailand. One influenza A virus was identified and characterized as an avian-like influenza virus H3N2. The virus was named A/canine/Thailand/CU-DC5299/12. A phylogenetic analysis indicated that the canine virus belonged to an avian Eurasian lineage and was genetically related to the canine influenza viruses H3N2 from China and Korea. This canine virus displays a unique genetic signature with two amino acid insertions in the NA protein, which is similar to the canine influenza viruses from eastern China (Zhejiang and Jiangsu). This study constitutes the first report of H3N2 canine influenza virus infection in a small-animal hospital in Thailand.
[Show abstract][Hide abstract] ABSTRACT: Quail has been proposed to be an intermediate host of influenza A viruses. However, information on the susceptibility and pathogenicity of pandemic H1N1 2009 (pH1N1) and swine influenza viruses in quails is limited. In this study, the pathogenicity, virus shedding, and transmission characteristics of pH1N1, swine H1N1 (swH1N1), and avian H3N2 (dkH3N2) influenza viruses in quails was examined. Three groups of 15 quails were inoculated with each virus and evaluated for clinical signs, virus shedding and transmission, pathological changes, and serological responses. None of the 75 inoculated (n = 45), contact exposed (n = 15), or negative control (n = 15) quails developed any clinical signs. In contrast to the low virus shedding titers observed from the swH1N1-inoculated quails, birds inoculated with dkH3N2 and pH1N1 shed relatively high titers of virus predominantly from the respiratory tract until 5 and 7 DPI, respectively, that were rarely transmitted to the contact quails. Gross and histopathological lesions were observed in the respiratory and intestinal tracts of quail inoculated with either pH1N1 or dkH3N2, indicating that these viruses were more pathogenic than swH1N1. Sero-conversions were detected 7 DPI in two out of five pH1N1-inoculated quails, three out of five quails inoculated with swH1N1, and four out of five swH1N1-infected contact birds. Taken together, this study demonstrated that quails were more susceptible to infection with pH1N1 and dkH3N2 than swH1N1.
[Show abstract][Hide abstract] ABSTRACT: Quail has been proposed as one of the intermediate hosts supporting the generation of newly reassortant influenza A viruses (IAVs) with the potential to infect humans. To evaluate the role of quail as an intermediate host of IAVs, co-infections of quail with swine-origin pandemic H1N1 2009 (pH1N1) and low pathogenic avian influenza (LPAI) duck H3N2 (dkH3N2) viruses (n=10) or endemic Thai swine H1N1 (swH1N1) and dkH3N2 viruses (n=10) were conducted. Three additional groups of five quail were each inoculated with pH1N1, swH1N1 and dkH3N2 as control groups to verify that each virus can infect quail. Our result showed that co-infected quail shed higher viral titers from the respiratory tract than single virus infected quail. This study confirmed that reassortant viruses could be readily generated in the respiratory tract of quail from both the pH1N1/dkH3N2 co-infected group (100% of quail generating reassortant viruses) and the swH1N1/dkH3N2 (33% of quail generating reassortant viruses) co-infected group without discernible clinical signs. The reassortment efficacy between the two combination of viruses was different in that the frequency of reassortant viruses was significantly higher in pH1N1/dkH3N2 co-infected quail (21.4%) compared to swH1N1/dkH3N2 co-infected quail (0.8%), indicating that gene combinations in pH1N1 have a higher potential to reassort with dkH3N2 compared to swH1N1. In summary, our result confirmed that quail could be an intermediate host of IAVs for generating new reassortant viruses. Our finding highlights the importance of monitoring IAVs especially pH1N1 in quail.
[Show abstract][Hide abstract] ABSTRACT: A recently emerged H1N1 Influenza A virus (pandemic H1N1 (pH1N1)) with a Swine influenza virus (SIV) genetic background spread globally from human-to-human causing the first influenza virus pandemic of the 21st century. In a short period, reverse zoonotic cases in pigs followed by a widespread of the virus in the pig population were documented. The implementation of effective control strategies, rapid diagnosis, and differentiation of such virus from endemically circulating SIV in the various swine populations of the world is needed. To address the problem, a multiplex reverse transcription polymerase chain reaction assay utilizing a combination of the PB1, H1, and N1 primers that can rapidly and simultaneously subtype and screen for the presence of pH1N1 virus infection in Thai pigs was developed. The assay had 100% specificity and did not amplify genetic material from other subtypes of SIV, seasonal H1N1 human influenza (huH1N1) virus, highly pathogenic influenza H5N1 virus, and other important swine respiratory viral pathogens. The assay was able to both detect and subtype pH1N1 virus as low as 0.1-50% tissue culture infective doses/ml (TCID(50)/ml). The assay was used to screen 175 clinical samples obtained from SIV suspected cases, of which 6 samples were pH1N1 positive and were confirmed through virus isolation and whole genome sequencing. The results of the study suggested that the assay would be useful for the rapid diagnosis of pH1N1 in suspected Thai swineherds, where genetics of the endemically circulating SIV differ from the strains circulating in North American and European herds.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 09/2011; 23(5):1017-21. · 1.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A swine influenza outbreak occurred on a commercial pig farm in Thailand. Outbreak investigation indicated that pigs were co-infected with pandemic (H1N1) 2009 virus and seasonal influenza (H1N1) viruses. No evidence of gene reassortment or pig-to-human transmission of pandemic (H1N1) 2009 virus was found during the outbreak.
[Show abstract][Hide abstract] ABSTRACT: We investigated influenza interspecies transmission in two commercial swine farms in Thailand. Sera from swine-exposed workers (n=78), age-matched non-swine-exposed healthy people (n=60) and swine populations in both farms (n=85) were studied. Hemagglutination-inhibition (HI) assay was performed on Thai swine H1 viruses (swH1N1 and swH1N2) isolated from both farms. Thai human H1N1 (huH1N1) and pandemic H1N1 2009 (pH1N1) were also used as test antigens. The hemagglutinin (HA) 1 genes of swH1N1 and swH1N2 viruses were sequenced and shown to be genetically distinct from the Thai huH1N1 and pH1N1 viruses. Evidence of pig-to-human influenza virus transmission was found in farm workers with increased odds of elevated antibody titers to both swH1N1 (OR 42.63, 95% CI, 14.65-124) and swH1N2 (OR 58, 95% CI, 13.12-256.3) viruses. No evidence of human-to-pig influenza virus transmission was detected in this study.