Katz Mark A, Muthoka Philip, Emukule Gideon O, Kalani Rosalia, Njuguna Henry, Waiboci Lilian W, Ahmed Jamal A, Bigogo Godfrey, Feikin Daniel R, Njenga Moses K, Breiman Robert F, Mott Joshua A
Centers for Disease Control and Prevention-Kenya/Kenya Medical Research Institute, Nairobi, Kenya.
Kenya Ministry of Health, Nairobi, Kenya.
PLoS One. 2014 Jun 23;9(6):e98615. doi: 10.1371/journal.pone.0098615. eCollection 2014.
Recent studies have shown that influenza is associated with significant disease burden in many countries in the tropics, but until recently national surveillance for influenza was not conducted in most countries in Africa.
In 2007, the Kenyan Ministry of Health with technical support from the CDC-Kenya established a national sentinel surveillance system for influenza. At 11 hospitals, for every hospitalized patient with severe acute respiratory illness (SARI), and for the first three outpatients with influenza-like illness (ILI) per day, we collected both nasopharyngeal and oropharyngeal swabs. Beginning in 2008, we conducted in-hospital follow-up for SARI patients to determine outcome. Specimens were tested by real time RT-PCR for influenza A and B. Influenza A-positive specimens were subtyped for H1, H3, H5, and (beginning in May 2009) A(H1N1)pdm09.
From July 1, 2007 through June 30, 2013, we collected specimens from 24,762 SARI and 14,013 ILI patients. For SARI and ILI case-patients, the median ages were 12 months and 16 months, respectively, and 44% and 47% were female. In all, 2,378 (9.6%) SARI cases and 2,041 (14.6%) ILI cases were positive for influenza viruses. Most influenza-associated SARI cases (58.6%) were in children <2 years old. Of all influenza-positive specimens, 78% were influenza A, 21% were influenza B, and 1% were influenza A/B coinfections. Influenza circulated in every month. In four of the six years influenza activity peaked during July-November. Of 9,419 SARI patients, 2.7% died; the median length of hospitalization was 4 days.
During six years of surveillance in Kenya, influenza was associated with nearly 10 percent of hospitalized SARI cases and one-sixth of outpatient ILI cases. Most influenza-associated SARI and ILI cases were in children <2 years old; interventions to reduce the burden of influenza, such as vaccine, could consider young children as a priority group.
近期研究表明，流感在许多热带国家造成了严重的疾病负担，但直到最近，非洲大多数国家仍未开展全国性的流感监测。
2007年，肯尼亚卫生部在肯尼亚疾病预防控制中心的技术支持下，建立了全国流感哨点监测系统。在11家医院，对于每例因严重急性呼吸道疾病（SARI）住院的患者，以及每天前来就诊的前3例流感样疾病（ILI）门诊患者，我们同时采集鼻咽拭子和口咽拭子。从2008年开始，我们对SARI患者进行住院随访以确定转归情况。标本通过实时逆转录聚合酶链反应（RT-PCR）检测甲型和乙型流感病毒。甲型流感病毒阳性标本进一步分型为H1、H3、H5以及（从2009年5月开始）甲型H1N1流感病毒（A(H1N1)pdm09）。
从2007年7月1日至2013年6月30日，我们共采集了24,762例SARI患者和14,013例ILI患者的标本。SARI和ILI病例患者的中位年龄分别为12个月和16个月，女性分别占44%和47%。共有2378例（9.6%）SARI病例和2041例（14.6%）ILI病例流感病毒检测呈阳性。大多数与流感相关的SARI病例（58.6%）为2岁以下儿童。在所有流感阳性标本中，78%为甲型流感，21%为乙型流感，1%为甲型/乙型流感病毒合并感染。流感全年均有传播。在六年中的四年里，流感活动在7月至11月达到高峰。在9419例SARI患者中，2.7%死亡；住院中位时长为4天。
在肯尼亚的六年监测期间，流感与近10%的SARI住院病例以及六分之一的ILI门诊病例相关。大多数与流感相关的SARI和ILI病例为2岁以下儿童；减轻流感负担的干预措施，如疫苗接种，可将幼儿作为优先群体加以考虑。
