ABSTRACT
Avian influenza (AI) A virus subtypes H5 and H7 cause severe disease in domestic poultry, including chickens and turkeys. Moreover, H5 and H7 AI A viruses can cross the species barrier from poultry to humans. In the present study, we have developed a single-step multiplex reverse transcription-polymerase chain reaction assay (RT-PCR) for detecting H5 and H7 AI A viruses. This assay was applied to the poultry isolates with the aim of establishing a surveillance method to monitor possible transmission to humans. Two subtype-specific primer sets capable of producing PCR products of 157 and 326 base pairs corresponding to AI A virus H5 and H7 subtypes, respectively, were utilized in a one-step and one-tube reaction. The single-step multiplex RT-PCR assay developed in this study was found to be specific for detecting H5 and H7 AI A viruses. No specific amplification bands were detected with total nucleic acids extracted from other influenza hemagglutinin subtypes and other viral pathogens. The sensitivity of this assay was about 10(3) RNA copies/microl. In conclusion, this novel single-step multiplex RT-PCR is a simple assay with high potential for rapid, specific and cost effective laboratory diagnosis of H5 and H7 AI A virus isolates from clinical specimens of poultry.
Subject(s)
Influenza A virus/genetics , Influenza in Birds/virology , Reverse Transcriptase Polymerase Chain Reaction/methods , Animals , Birds/virology , Electrophoresis, Agar Gel , Influenza A Virus, H5N1 Subtype/genetics , Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza A Virus, H7N7 Subtype/genetics , Influenza A Virus, H7N7 Subtype/isolation & purification , Influenza A virus/classification , Influenza A virus/isolation & purification , Influenza in Birds/diagnosis , RNA, Viral/genetics , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Influenza virus is not known to affect wild felids. We demonstrate that avian influenza A (H5N1) virus caused severe pneumonia in tigers and leopards that fed on infected poultry carcasses. This finding extends the host range of influenza virus and has implications for influenza virus epidemiology and wildlife conservation.
