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[MEDSCAPE新闻]:中国的H7N9禽流感疫情继续恶化
2017年09月22日 时讯速递, 进展交流 暂无评论

H7N9 Avian Flu Continues to Spread, Worsen in China

Janis C. Kelly

September 12, 2017

The latest epidemic of Asian lineage avian influenza A (Asian H7N9) in China infected almost as many patients as the four previous outbreaks combined and gave rise to a variant less susceptible to available treatments and vaccines, researchers report in an article  published in the September 8 issue of the Morbidity and Mortality Weekly Report.

研究人员在Morbidity and Mortality Weekly Report杂志9月份第8期发表的一篇文章报告,中国最近一次亚洲来源甲型禽流感(Asian H7N9)疫情的感染人数几乎相当于既往四次暴发流行的患者数总和,并且分离到的变异病毒对现有治疗及疫苗敏感性降低。

The fifth annual epidemic, which occurred from October 1, 2016, through July 31, 2017, included 759 patients and 281 deaths (37%). The cumulative mortality for all five Asian H7N9 outbreaks since February 2013 is 39% (605 of 1557 patients).

第五年的疫情始于2016年10月1日,截止2017年7月31日,共报告759名患者,其中281例(37%)死亡。自2013年2月以来,亚洲H7N9五次暴发流行累计病死率为39% (605/1557)。

"Although human infections with Asian H7N9 viruses from poultry are rare and no efficient or sustained human-to-human transmission has been detected, when human infections do occur, they are associated with severe illness and high mortality," write James C. Kile, DVM, from the Influenza Division at the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, and colleagues. "Continued vigilance is important to identify changes in the virus that might have epidemiologic implications, such as increased transmission from poultry to humans or transmission between humans."

“尽管人从家禽感染亚洲H7N9的情况非常少见,且未发现有效的或持续的人与人的传播,然而,一旦发生人类感染,疾病非常严重,病死率很高,”位于乔治亚州亚特兰大的疾病控制预防中心(CDC)国家免疫及呼吸疾病中心流感部门的James C. Kile及其同事写到,“持续监测对于发现有流行病学意义的病毒变异非常重要,如由家禽向人类的传播或人与人之间的传播增强等。”

The fifth outbreak involved all but three of 33 provinces, regions, and municipalities in China. All infected patients had either lived in or traveled to these areas, and most (90%) infections were associated with poultry exposure, especially at live bird markets.

第五次暴发流行累及了中国33个省市自治区的30个。所有感染患者或居住在这些地区,或曾前往这些地区旅行,大多数(90%)的感染患者有家禽暴露史,特别是活禽市场。

FIGURE 1. Confirmed Asian lineage avian influenza A(H7N9) virus infections of humans reported to the World Health Organization (N = 1,557),* by month of illness onset — China,† February 19, 2013–August 7, 2017

Source: Publically released infections in Disease Outbreak News (http://www.who.int/csr/don/en/) or Human-Animal Interface Monthly Report (http://www.who.int/influenza/human_animal_interface/en/).

* Date of onset missing for six infections.

One case was exported to Malaysia (January 2014) and two to Canada (January 2015).

The figure above is a histogram showing confirmed Asian lineage avian influenza A(H7N9) virus infections of humans reported to the World Health Organization (N = 1,557), by month of illness onset in China during February 19, 2013–August 7, 2017.

FIGURE 2. Geographic distribution of Asian lineage avian influenza A(H7N9) virus infections of humans reported to the World Health Organization — China,* A) epidemic 5 (October 1, 2016–August 7, 2017) and B) epidemics 1–4 (March 2013–September 30, 2016)

Source: Publically released infections in Disease Outbreak News (http://www.who.int/csr/don/en/) or Human-Animal Interface Monthly Report (http://www.who.int/influenza/human_animal_interface/en/).

* Avian influenza A(H7N9) virus infections of humans reported in mainland China, Hong Kong, Macao, and Taiwan.

 

The authors note, however, that the increase in infections was the result of wider geographic spread and higher prevalence of Asian H7N9 viruses among poultry, not increased poultry-to-human or human-to-human transmission.

然而,作者也指出,感染病例的增加是更规范地域传播及家禽中亚洲H7N9病毒感染率升高的后果,并非由家禽向人的传播或人与人之间的传播增加所致。

Notably, during the fifth epidemic, some Asian H7N9 strains acquired mutations that turned them from low-pathogenic to high-pathogenic strains. Twenty-seven patients were infected with high-pathogenic avian influenza strains that had acquired mutations.

需要指出的是,在第五次流行中,部分亚洲H7N9病毒株出现了突变,致使其从低致病性向高致病性病毒株转变。27例患者感染了发生突变的高致病性禽流感病毒株。

Sequencing data from 166 viral isolates collected during the fifth epidemic uncovered genetic markers of resistance to amantadine and rimantadine. In addition, researchers found significant changes in surface proteins among some of the high-pathogenic avian influenza strains, making them less similar to previous candidate vaccine viruses.

在第五次流行中收集的166株病毒测序结果发现了对金刚烷胺及金刚烷乙胺耐药的基因标志物。另外,研究人员还发现,部分高致病性禽流感病毒株的表面蛋白发生显著改变,因而与既往的疫苗病毒相似性减小。

These factors contributed to the CDC's decision to classify Asian H7N9 as the virus with the highest potential pandemic risk among all viruses evaluated using the Influenza Risk Assessment Tool.

这些因素使得CDC决定,在根据流感风险评估工具评估的所有病毒中,亚洲H7N9被划分为全球流行风险最高的病毒。

The government of China is trying to minimize Asian H7N9 spread by promoting large-scale farming and centralized slaughtering, improving poultry product handling, and routinely closing, cleaning, and disinfecting live poultry markets and enhancing surveillance for influenza-like illness.

中国政府正在通过促进大规模养殖及集中屠宰,改进家禽产品处理流程,常规关闭活禽市场并进行清洗和消毒,同时加强对流感样疾病的监测等措施,减少亚洲H7N9的传播。

The authors write, "CDC has partnered with China CDC, and other China government organizations, United Nations organizations, and surrounding countries to enhance surveillance and laboratory capacity to detect and respond to Asian H7N9 in animals and humans."

作者写到:“CDC正在与中国CDC、中国政府的其他部门、联合国机构以及周边国家合作,以加强监测和实验室能力,以发现并应对动物和人的亚洲H7N9疫情。”

One coauthor holds two US patents for influenza vaccines. The other authors have disclosed no relevant financial relationships.

Morb Mortal Wkly Rep. 2017;66:928-932. Full text

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