Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar.
Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar.
复制标题
DOI：
10.1371/journal.pntd.0004827
复制
发表时间：
2016-07
影响因子：
3.8
通讯作者：
Heraud JM
中科院分区：
文献类型：
--
作者：
Olive MM;Chevalier V;Grosbois V;Tran A;Andriamandimby SF;Durand B;Ravalohery JP;Andriamamonjy S;Rakotomanana F;Rogier C;Heraud JM
裂谷热是一种影响反刍动物和人类的病媒传播疾病。马达加斯加在2008-2009年受到裂谷热的严重影响，有证据表明这一疾病的大规模和异质传播。查明高危环境对于通过在马达加斯加开展裂谷热监测来优化现有资源至关重要。在此，我们的研究目标是：（一）确定有利于裂谷热向牛和人传播的环境因素和地区，（二）确定马达加斯加人的环境中有利于人类感染的人类行为。首先，我们使用多因素分析（MFA）的特点马达加斯加公社的环境。然后，我们使用广义线性混合模型分析了在国家一级收集的牛和人血清学数据，以个体血清学状态（牛或人）作为响应，MFA因子以及其他潜在风险因素（牛密度，人类行为）作为解释变量。牛和人的血清阳性率与潮湿环境呈正相关（p<0.001）。牛密度高的地区处于危险之中（p<0.01; OR = 2.6）。此外，我们的分析表明，经常接触生奶有助于解释人类感染（OR = 1.6）。最后，我们的研究强调，东海岸、西部和西北部是裂谷热牛传播的高风险地区。我们分析环境、牛和人类数据集的综合方法使我们能够对马达加斯加裂谷热的传播模式提出新的见解。牛血清阳性率、潮湿环境和高牛密度之间的关联表明，伴随的病媒传播和直接传播对于维持裂谷热的地方性传播至关重要。此外，在西部、西北部和东部沿海地区的危险潮湿环境中，库蚊和按蚊适宜，牛和人都可能发生病媒传播。可以通过数学建模进一步评估媒介传播或直接传播的相对作用。裂谷热病毒（RVFV）是一种引起媒介传播的热带疾病的病原体。该疾病影响反刍动物和人类，并严重影响受影响国家的健康和经济。2008-2009年，马达加斯加受到裂谷热的严重影响，有证据表明这一疾病的大规模和异质传播。我们的研究旨在确定RVFV传播的环境和人类相关风险因素。首先，我们根据其对RVFV蚊子密度和种群动态的影响来描述马达加斯加的环境。然后，我们统计分析了牛和人的血清学数据收集在国家一级的个人血清学状态的响应，和马达加斯加的环境以前的特点是气候和景观变量以及其他潜在的风险因素作为解释变量。我们的研究结果确定了该岛西部、西北部和东部的潮湿环境为危险地区。风险环境的识别对于集中兽医监测和RVFV控制至关重要。
Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008–2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts. First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001). Areas with high cattle density were at risk (p<0.01; OR = 2.6). Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6). Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle. Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution of vectorial or direct transmissions could be further assessed by mathematic modelling. Rift Valley fever virus (RVFV) is a pathogen that causes a vector-borne tropical disease. The disease affects ruminants and humans and severely impacts the health and economy of affected countries. Madagascar was heavily affected by Rift Valley fever (RVF) in 2008–2009, with evidence of a large and heterogeneous spread of the disease. Our study aims at identifying environmental and human-related risk factors for RVFV transmission. First, we characterized Malagasy environments according to their putative influence on RVFV mosquito density and population dynamics. Then we statistically analyzed cattle and human serological data collected at a national level with the individual serological status as response, and Malagasy environments previously characterized by climatic and landscape variables as well as other potential risk factors as explanatory variables. Our results identified humid environments of the western, north-western and eastern parts of the island as risky areas. The identification of at-risk environments is essential to focus veterinary surveillance and control of RVFV.