Background:To monitor carrier hosts of avian influenza in Nigeria,we randomly collected cloaca swab specimens from 155 ducks at a live bird market(LBM)in Ibadan,southwest Nigeria,between July 2011 and July 2012.Method...Background:To monitor carrier hosts of avian influenza in Nigeria,we randomly collected cloaca swab specimens from 155 ducks at a live bird market(LBM)in Ibadan,southwest Nigeria,between July 2011 and July 2012.Methods:The samples were analyzed by real-time reverse transcription-polymerase chain reaction(RT-PCR)and virus isolation was carried out in embryonated chicken eggs.Partial sequencing of the antigenic cleavage site of the haemagglutinin(HA)gene was performed,multiple sequence alignment was carried out using ClustalW,and a phylogenetic tree was constructed using the neighbor joining method.Results:Twenty(13%)of the 155 samples were positive for avian influenza subtype H5N2 by real-time RT-PCR and three isolates were obtained from embryonated chicken eggs.Partial sequencing of the amino acid cleavage site of the HA genes of two isolates corresponded to a PQRETGL*F sequence that is common in low pathogenic avian influenza(LPAI).Phylogenetically,the HA genes of the two influenza viruses are monophyletic and clustered with H5N2 viruses detected in wild ducks from Africa.Conclusion:The occurrence of LPAI in domestic ducks in Nigeria underscores the importance of continuous surveillance and monitoring of the virus(in a country that is considered to be free of avian influenza)in order to prevent the emergence of virulent strains that may spread to commercial poultry and humans.展开更多
Birds are an indispensable part of nature andthey play an important role in maintaining an ecologicalbalance. The existence of bird markets undoubtedlyposes a threat to the population of wild birds. Thegeographical lo...Birds are an indispensable part of nature andthey play an important role in maintaining an ecologicalbalance. The existence of bird markets undoubtedlyposes a threat to the population of wild birds. Thegeographical location of Beijing is paramount to themigratory birds. The species of birds are rich in varietyand its quantity is large in scale. In addition, the birdmarket in old town Beijing has a long history - since theQing Dynasty, it has been the main bird market in thecity. Therefore, a survey of the major bird markets inthe city is highly representative. This study investigatedthe types, quantities, and prices of wild birds tradedin several major bird markets in Beijing from July16 to July 18, 2019. Data analysis and collation werealso conducted in this study. The results of the surveypresented 26 kinds of wild birds, with a total tradingvolume of an estimated 253. They are mainly birdsof the order of the passerine, 18 of which are underBeijing’s second-class protection, and one of them isunder first-class protection.展开更多
文摘Background:To monitor carrier hosts of avian influenza in Nigeria,we randomly collected cloaca swab specimens from 155 ducks at a live bird market(LBM)in Ibadan,southwest Nigeria,between July 2011 and July 2012.Methods:The samples were analyzed by real-time reverse transcription-polymerase chain reaction(RT-PCR)and virus isolation was carried out in embryonated chicken eggs.Partial sequencing of the antigenic cleavage site of the haemagglutinin(HA)gene was performed,multiple sequence alignment was carried out using ClustalW,and a phylogenetic tree was constructed using the neighbor joining method.Results:Twenty(13%)of the 155 samples were positive for avian influenza subtype H5N2 by real-time RT-PCR and three isolates were obtained from embryonated chicken eggs.Partial sequencing of the amino acid cleavage site of the HA genes of two isolates corresponded to a PQRETGL*F sequence that is common in low pathogenic avian influenza(LPAI).Phylogenetically,the HA genes of the two influenza viruses are monophyletic and clustered with H5N2 viruses detected in wild ducks from Africa.Conclusion:The occurrence of LPAI in domestic ducks in Nigeria underscores the importance of continuous surveillance and monitoring of the virus(in a country that is considered to be free of avian influenza)in order to prevent the emergence of virulent strains that may spread to commercial poultry and humans.
文摘Birds are an indispensable part of nature andthey play an important role in maintaining an ecologicalbalance. The existence of bird markets undoubtedlyposes a threat to the population of wild birds. Thegeographical location of Beijing is paramount to themigratory birds. The species of birds are rich in varietyand its quantity is large in scale. In addition, the birdmarket in old town Beijing has a long history - since theQing Dynasty, it has been the main bird market in thecity. Therefore, a survey of the major bird markets inthe city is highly representative. This study investigatedthe types, quantities, and prices of wild birds tradedin several major bird markets in Beijing from July16 to July 18, 2019. Data analysis and collation werealso conducted in this study. The results of the surveypresented 26 kinds of wild birds, with a total tradingvolume of an estimated 253. They are mainly birdsof the order of the passerine, 18 of which are underBeijing’s second-class protection, and one of them isunder first-class protection.
