Hassan Mohammad M, El Zowalaty Mohamed E, Islam Ariful, Rahman Md M, Chowdhury Md N U, Nine Hatem S M Z, Rahman Md K, Järhult Josef D, Hoque Md A
Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram 4225, Bangladesh.
Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, UAE.
Vet Sci. 2020 Sep 1;7(3):122. doi: 10.3390/vetsci7030122.
Avian influenza (AI) is endemic and frequently causes seasonal outbreaks in winter in Bangladesh due to high pathogenic avian influenza (HPAI) H5N1 and low pathogenic avian influenza (LPAI) H9N2. Among avian influenza A viruses (AIV), H5, H7, and H9 subtypes have the most zoonotic potential. Captive birds in zoos and safari parks are used for educational, recreational, breeding, and conservational purposes in Bangladesh. To screen for AIV in captive birds to assess potential public health threats, we conducted a cross-sectional study in two safari parks and one zoo in Bangladesh for four months, from November to December 2013 and from January to February 2014. We collected blood samples, oropharyngeal, and cloacal swabs from 228 birds. We tested serum samples for AIV antibodies using competitive enzyme-linked immunosorbent assay (c-ELISA) and AIV sero-subtype H5, H7, and H9 using hemagglutination inhibition (HI) test. Swab samples were tested for the presence of avian influenza viral RNA using real-time reverse transcription-polymerase chain reaction (rRT-PCR). Across all the samples, AIV antibody prevalence was 9.7% (95% CI: 6.1-14.2, n = 228) and AIV HA subtype H5, H7 and H9 sero-prevalence was 0% (95% CI: 0-1.6, n = 228), 0% (95% CI: 0-1.6, n = 228) and 6.6% (95% CI: 3.72-10.6, n = 228), respectively. No AI viral RNA (M-gene) was detected in any swab sample (0%, 95% CI: 0-1.6, n = 228). Birds in the Safari park at Cox's Bazar had a higher prevalence in both AIV antibody prevalence (13.5%) and AIV H9 sero-prevalence (9.6%) than any of the other sites, although the difference was not statistically significant. Among eight species of birds, Emu () had the highest sero-positivity for both AIV antibody prevalence (26.1%) and AIV H9 prevalence (17.4%) followed by Golden pheasant () with AIV antibody prevalence of 18.2% and AIV H9 prevalence of 11.4%. Our results highlight the presence of AI antibodies indicating low pathogenic AIV mingling in captive birds in zoos and safari parks in Bangladesh. Continuous programmed surveillance is therefore recommended to help better understand the diversity of AIVs and provide a clear picture of AI in captive wild birds, enabling interventions to reduce the risk of AIV transmission to humans.
由于高致病性禽流感（HPAI）H5N1和低致病性禽流感（LPAI）H9N2，禽流感（AI）在孟加拉国呈地方流行性，且经常在冬季引发季节性疫情。在甲型禽流感病毒（AIV）中，H5、H7和H9亚型具有最大的人畜共患病潜力。孟加拉国动物园和野生动物园中的圈养鸟类用于教育、娱乐、繁殖和保护目的。为了筛查圈养鸟类中的AIV以评估潜在的公共卫生威胁，我们于2013年11月至12月以及2014年1月至2月在孟加拉国的两个野生动物园和一个动物园进行了为期四个月的横断面研究。我们从228只鸟类中采集了血液样本、口咽拭子和泄殖腔拭子。我们使用竞争酶联免疫吸附测定（c-ELISA）检测血清样本中的AIV抗体，并使用血凝抑制（HI）试验检测AIV血清亚型H5、H7和H9。拭子样本使用实时逆转录聚合酶链反应（rRT-PCR）检测禽流感病毒RNA的存在。在所有样本中，AIV抗体阳性率为9.7%（95%置信区间：6.1 - 14.2，n = 228），AIV HA亚型H5、H7和H9的血清阳性率分别为0%（95%置信区间：0 - 1.6，n = 228）、0%（95%置信区间：0 - 1.6，n = 228）和6.6%（95%置信区间：3.72 - 10.6，n = 228）。在任何拭子样本中均未检测到AI病毒RNA（M基因）（0%，95%置信区间：0 - 1.6，n = 228）。科克斯巴扎尔野生动物园的鸟类在AIV抗体阳性率（13.5%）和AIV H9血清阳性率（9.6%）方面均高于其他任何地点，尽管差异无统计学意义。在八种鸟类中，鸸鹋（）的AIV抗体阳性率（26.1%）和AIV H9阳性率（17.4%）最高，其次是红腹锦鸡（），AIV抗体阳性率为18.2%，AIV H9阳性率为11.4%。我们的结果突出表明在孟加拉国动物园和野生动物园的圈养鸟类中存在AI抗体，表明有低致病性AIV混入。因此，建议进行持续的定期监测，以更好地了解AIV的多样性，并清晰呈现圈养野生鸟类中的禽流感情况，从而采取干预措施降低AIV传播给人类的风险。
