Soliman Atef, Saad Magdi, Elassal Emad, Amir Ehab, Plathonoff Chantal, Bahgat Verina, El-Badry Maha, Ahmed Lu'ay S, Fouda Mostafa, Gamaleldin Mohammed, Mohamed Nahed Abd-Elal, Salyer Stephanie, Cornelius Claire, Barthel Robert
US Naval Medical Research Unit Number 3, 3A Imtidad Ramses St., Abassia, Cairo, Egypt.
J Wildl Dis. 2012 Jul;48(3):669-75. doi: 10.7589/0090-3558-48.3.669.
Migratory (particularly aquatic) birds are the major natural reservoirs for type A influenza viruses. However, their role in transmitting highly pathogenic avian influenza (HPAI) viruses is unclear. Egypt is a "funnel" zone of wild bird migration pathways from Central Asia and Europe to Eastern and Central Africa ending in South Africa. We sought to detect and isolate avian influenza viruses in migratory birds in Egypt. During September 2003-February 2009, the US Naval Medical Research Unit Number 3, Cairo, Egypt, in collaboration with the Egyptian Ministry of Environment, obtained cloacal swabs from 7,894 migratory birds captured or shot by hunters in different geographic areas in Egypt. Samples were processed by real-time reverse transcriptase PCR for detection of the influenza A matrix gene. Positive samples were processed for virus isolation in specific-pathogen-free embryonated eggs and isolates were subtyped by PCR and partial sequencing. Ninety-five species of birds were collected. Predominant species were Green-Winged Teal (Anas carolinensis; 32.0%, n=2,528), Northern Shoveler (Anas clypeata; 21.4%, n=1,686), and Northern Pintail (Anas acuta; 11.1%, n=877). Of the 7,894 samples, 745 (9.4%) were positive for the influenza A matrix gene (mainly from the above predominant species). Thirteen of the 745 (1.7%) were H5-positive by PCR (11 were low-pathogenic avian influenza and two were HPAI H5N1). The prevalences of influenza A was among regions were 10-15%, except in Middle Egypt (4%). Thirty-nine influenza isolates were obtained from PCR-positive samples. Seventeen subtypes of avian influenza viruses (including H5N1 and H7N7) were classified from 39 isolates using PCR and partial sequencing. Only one HPAI H5N1 was isolated in February 2006, from a wild resident Great Egret (Ardea alba). No major die-offs or sick migratory birds were detected during the study. We identified avian influenza virus subtypes not previously reported in Egypt. The HPAI H5N1 isolated or detected indicates that migratory birds may play a role in the dispersal of HPAI virus, but a detailed mechanism of this role needs to be elucidated.
候鸟（尤其是水鸟）是甲型流感病毒的主要天然宿主。然而，它们在传播高致病性禽流感（HPAI）病毒方面的作用尚不清楚。埃及是从中亚和欧洲到东非和中非并最终抵达南非的野生鸟类迁徙路线的“漏斗”区。我们试图在埃及的候鸟中检测和分离禽流感病毒。在2003年9月至2009年2月期间，美国海军第三医学研究单位（位于埃及开罗）与埃及环境部合作，从埃及不同地理区域的猎人捕获或射杀的7894只候鸟中采集泄殖腔拭子。通过实时逆转录聚合酶链反应（PCR）对样本进行处理，以检测甲型流感病毒基质基因。对阳性样本在无特定病原体的鸡胚中进行病毒分离，分离株通过PCR和部分测序进行亚型鉴定。共收集了95种鸟类。优势物种为绿翅鸭（Anas carolinensis；32.0%，n = 2528）、琵嘴鸭（Anas clypeata；21.4%，n = 1686）和针尾鸭（Anas acuta；11.1%，n = 877）。在7894份样本中，745份（9.4%）甲型流感病毒基质基因呈阳性（主要来自上述优势物种）。745份样本中有13份（1.7%）通过PCR检测为H5阳性（11份为低致病性禽流感，2份为HPAI H5N1）。除埃及中部（4%）外，各地区甲型流感的流行率为10 - 15%。从PCR阳性样本中获得了39株流感病毒分离株。使用PCR和部分测序从39株分离株中鉴定出17种禽流感病毒亚型（包括H5N1和H7N7）。仅在2006年2月从一只野生常驻大白鹭（Ardea alba）中分离出1株HPAI H5N1。在研究期间未检测到大规模死亡或患病的候鸟。我们鉴定出了埃及以前未报告过的禽流感病毒亚型。分离或检测到的HPAI H5N1表明候鸟可能在HPAI病毒的传播中起作用，但这一作用的详细机制有待阐明。
