Hassan Mohammad Mahmudul, Hoque Md Ahasanul, Ujvari Beata, Klaassen Marcel
Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia; Faculty of Veterinary Medicine, Chittagong Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chittagong, 4225, Bangladesh.
Faculty of Veterinary Medicine, Chittagong Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chittagong, 4225, Bangladesh.
Prev Vet Med. 2018 Aug 1;156:22-27. doi: 10.1016/j.prevetmed.2018.05.003. Epub 2018 May 2.
Live bird markets (LBM) are important for trading poultry in many developing countries where they are being considered hotspots of Avian Influenza Virus (AIV) prevalence and contamination. An active surveillance for Avian Influenza Virus (AIV) was conducted on four species of LBM birds (chickens, ducks, quails and pigeons) from 10 of the largest LBM in Chittagong, Bangladesh, and two species of peri-domestic wild birds (house crow and Asian pied starling) in their direct vicinity from November 2012 until September 2016. Our aim was to identify the scale and annual pattern of AIV circulation in both the LBM birds and the two per-domestic wild bird species living in close proximity of the LBM. In the latter two species, the annual pattern in AIV antibody prevalence was additionally investigated. A total of 4770 LBM birds and 1119 peri-domestic wild birds were sampled. We used rt-PCR for detection of the AIV M-gene and AIV subtypes H5, H7 and H9 from swab samples. We used c-ELISA for AIV antibody detection from serum samples of peri-domestic wild birds. Average AIV prevalence among the four LBM species varied between 16 and 28%, whereas no AIV was detected in peri-domestic wild birds by rt-PCR. In all LBM species we found significantly higher AIV prevalence in winter compared to summer. A similar pattern was found in AIV antibody prevalence in peri-domestic wild birds feeding in the direct vicinity of LBM. For the subtypes of AIV investigated, we found a significantly higher proportion of AIV H5 in LBM chickens and H9 in LBM ducks. No H7 was detected in any of the investigated samples. We conclude that AIV and notably AIV H5 and H9 were circulating in the investigated LBM of Bangladesh with clear seasonality that matched the prevalence of AIV antibodies of peri-domestic wild birds. These patterns show great resemblance to the annual outbreak patterns in Bangladeshi poultry industry. Our data suggest considerable exchange of AIV within and among the four LBM bird species and peri-domestic wild birds, which likely contributes to the maintenance of the AIV problems in Bangladesh. Increasing biosecurity and notably reducing the direct and indirect mixing of various domestic bird species and peri-domestic wild birds and developing all-in-all-out selling systems with regular use of disinfectant are likely to reduce the risk of transmission and spread of AIV, including HPAI.
活禽市场(LBM)在许多发展中国家的家禽交易中至关重要,这些国家将其视为禽流感病毒(AIV)流行和污染的热点地区。2012年11月至2016年9月,对孟加拉国吉大港10个最大的活禽市场的4种活禽市场鸟类(鸡、鸭、鹌鹑和鸽子)以及紧邻市场的2种家养野生鸟类(家鸦和亚洲 pied 椋鸟)进行了禽流感病毒(AIV)的主动监测。我们的目的是确定活禽市场鸟类以及紧邻活禽市场生活的2种家养野生鸟类中AIV传播的规模和年度模式。对于后两种鸟类,还额外研究了AIV抗体流行率的年度模式。总共对4770只活禽市场鸟类和1119只家养野生鸟类进行了采样。我们使用逆转录聚合酶链反应(rt-PCR)从拭子样本中检测AIV M基因以及AIV H5、H7和H9亚型。我们使用竞争酶联免疫吸附测定(c-ELISA)从家养野生鸟类的血清样本中检测AIV抗体。4种活禽市场鸟类中的AIV平均流行率在16%至28%之间,而通过rt-PCR在家养野生鸟类中未检测到AIV。在所有活禽市场鸟类中,我们发现冬季的AIV流行率显著高于夏季。在紧邻活禽市场觅食的家养野生鸟类的AIV抗体流行率中也发现了类似模式。对于所研究的AIV亚型,我们发现活禽市场鸡中的AIV H5比例显著更高,活禽市场鸭中的AIV H9比例显著更高。在所研究的任何样本中均未检测到H7。我们得出结论,AIV尤其是AIV H5和H9在孟加拉国所研究的活禽市场中传播,具有明显的季节性,与家养野生鸟类的AIV抗体流行率相匹配。这些模式与孟加拉国家禽业的年度暴发模式极为相似。我们的数据表明,AIV在4种活禽市场鸟类和家养野生鸟类内部及之间大量传播,这可能是孟加拉国AIV问题持续存在的原因。加强生物安全措施,特别是减少各种家禽和家养野生鸟类的直接和间接混养,并建立定期使用消毒剂的全进全出销售系统,可能会降低包括高致病性禽流感(HPAI)在内的AIV传播和扩散的风险。