Koutangni Thibaut, Boubacar Maïnassara Halima, Mueller Judith E
EHESP French School of Public Health, Sorbonne Paris Cité, Rennes, France; Institut Pasteur, Emerging Diseases Epidemiology Unit, Paris, France.
Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger.
PLoS One. 2015 Feb 6;10(2):e0116725. doi: 10.1371/journal.pone.0116725. eCollection 2015.
To facilitate the interpretation of meningococcal meningitis epidemiology in the "African meningitis belt", we aimed at obtaining serogroup-specific pooled estimates of incidence, carriage and case-carrier ratios for meningococcal meningitis in the African meningitis belt and describe their variations across the endemic, hyperendemic and epidemic context.
We conducted a systematic review and meta-analysis of studies reporting serogroup-specific meningococcal meningitis monthly incidence and carriage in the same population and time period. Epidemiological contexts were defined as endemic (wet season, no epidemic), hyperendemic (dry season, no epidemic), and epidemic (dry season, epidemic).
FINDINGS: Eight studies reporting a total of eighty pairs of serogroup-specific meningococcal meningitis incidence and carriage estimates were included in this review. For serogroup A, changes associated with the transition from endemic to hyperendemic incidence and from hyperendemic to epidemic incidence were 15-fold and 120-fold respectively. Changes in carriage prevalence associated with both transitions were 1-fold and 30-fold respectively. For serogroup W and X, the transition from endemic to hyperendemic incidence involved a 4-fold and 1•1-fold increase respectively. Increases in carriage prevalence for the later transition were 7-fold and 1•7-fold respectively. No data were available for the hyperendemic-epidemic transition for these serogroups. Our findings suggested that the regular seasonal variation in serogroup A meningococcal meningitis incidence between the rainy and the dry season could be mainly driven by seasonal change in the ratio of clinical cases to subclinical infections. In contrast appearance of epidemic incidences is related to a substantial increase in transmission and colonisation and to lesser extent with changes in the case-carrier ratio.
Seasonal change in the rate of progression to disease given carriage together with variations in frequency of carriage transmission should be considered in models attempting to capture the epidemiology of meningococcal meningitis and mainly to predict meningitis epidemics in the African meningitis belt.
为便于解读“非洲脑膜炎带”的脑膜炎球菌性脑膜炎流行病学情况，我们旨在获取非洲脑膜炎带脑膜炎球菌性脑膜炎血清群特异性发病率、带菌率及病例 - 带菌者比例的汇总估计值，并描述其在地方性、高度地方性和流行性环境中的变化情况。
我们对在同一人群和时间段内报告血清群特异性脑膜炎球菌性脑膜炎月发病率和带菌率的研究进行了系统评价和荟萃分析。流行病学环境被定义为地方性（雨季，无疫情）、高度地方性（旱季，无疫情）和流行性（旱季，有疫情）。
本综述纳入了八项研究，共报告了八十对血清群特异性脑膜炎球菌性脑膜炎发病率和带菌率估计值。对于A群，从地方性发病率转变为高度地方性发病率以及从高度地方性发病率转变为流行性发病率时，发病率的变化分别为15倍和120倍。与这两种转变相关的带菌率变化分别为1倍和30倍。对于W群和X群，从地方性发病率转变为高度地方性发病率时，发病率分别增加了4倍和1.1倍。后一种转变时带菌率的增加分别为7倍和1.7倍。这些血清群在高度地方性 - 流行性转变方面没有可用数据。我们的研究结果表明，A群脑膜炎球菌性脑膜炎发病率在雨季和旱季之间的常规季节性变化可能主要由临床病例与亚临床感染比例的季节性变化驱动。相比之下，流行性发病率的出现与传播和定植的大幅增加有关，在较小程度上与病例 - 带菌者比例的变化有关。
在试图描述脑膜炎球菌性脑膜炎流行病学情况，特别是预测非洲脑膜炎带脑膜炎疫情的模型中，应考虑带菌情况下疾病进展速率的季节性变化以及带菌传播频率的变化。
