Métras Raphaëlle, Cavalerie Lisa, Dommergues Laure, Mérot Philippe, Edmunds W John, Keeling Matt J, Cêtre-Sossah Catherine, Cardinale Eric
Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom.
UMR CMAEE, CIRAD, Sainte-Clotilde, La Réunion, France.
PLoS Negl Trop Dis. 2016 Jun 22;10(6):e0004783. doi: 10.1371/journal.pntd.0004783. eCollection 2016 Jun.
Rift Valley fever (RVF) is a zoonotic arboviral disease that is a threat to human health, animal health and production, mainly in Sub-Saharan Africa. RVF virus dynamics have been poorly studied due to data scarcity. On the island of Mayotte in the Indian Ocean, off the Southeastern African coast, RVF has been present since at least 2004. Several retrospective and prospective serological surveys in livestock have been conducted over eleven years (2004-15). These data are collated and presented here. Temporal patterns of seroprevalence were plotted against time, as well as age-stratified seroprevalence. Results suggest that RVF was already present in 2004-07. An epidemic occurred between 2008 and 2010, with IgG and IgM peak annual prevalences of 36% in 2008-09 (N = 142, n = 51, 95% CI [17-55]) and 41% (N = 96, n = 39, 95% CI [25-56]), respectively. The virus seems to be circulating at a low level since 2011, causing few new infections. In 2015, about 95% of the livestock population was susceptible (IgG annual prevalence was 6% (N = 584, n = 29, 95% CI [3-10])). Monthly rainfall varied a lot (2-540mm), whilst average temperature remained high with little variation (about 25-30°C). This large dataset collected on an insular territory for more than 10 years, suggesting a past epidemic and a current inter-epidemic period, represents a unique opportunity to study RVF dynamics. Further data collection and modelling work may be used to test different scenarios of animal imports and rainfall pattern that could explain the observed epidemiological pattern and estimate the likelihood of a potential re-emergence.
裂谷热（RVF）是一种人畜共患的虫媒病毒病，主要在撒哈拉以南非洲地区对人类健康、动物健康及生产构成威胁。由于数据匮乏，对裂谷热病毒动态的研究一直很少。在非洲东南海岸外印度洋上的马约特岛，至少自2004年以来就存在裂谷热。在11年（2004 - 2015年）间对牲畜进行了多次回顾性和前瞻性血清学调查。现将这些数据整理并呈现于此。绘制了血清阳性率的时间模式图以及按年龄分层的血清阳性率图。结果表明，裂谷热在2004 - 2007年就已存在。2008年至2010年发生了一次疫情，2008 - 2009年IgG和IgM的年度患病率峰值分别为36%（N = 142，n = 51，95%可信区间[17 - 55]）和41%（N = 96，n = 39，95%可信区间[25 - 56]）。自2011年以来，该病毒似乎在低水平传播，导致的新感染很少。2015年，约95%的牲畜群体易感（IgG年度患病率为6%（N = 584，n = 29，95%可信区间[3 - 10]））。月降雨量变化很大（2 - 540毫米），而平均温度一直较高且变化不大（约25 - 3摄氏度）。在一个岛屿地区收集的这个超过10年的大型数据集表明过去曾有疫情且当前处于疫情间期，这是研究裂谷热动态的独特机会。进一步的数据收集和建模工作可用于测试不同的动物进口和降雨模式情景，这些情景可以解释观察到的流行病学模式并估计潜在再次出现的可能性。
