High Seroprevalence of Rift Valley Fever and Evidence for Endemic Circulation in Mbeya Region, Tanzania, in a Cross-Sectional Study
High Seroprevalence of Rift Valley Fever and Evidence for Endemic Circulation in Mbeya Region, Tanzania, in a Cross-Sectional Study
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DOI：
10.1371/journal.pntd.0001557
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发表时间：
2012-03-01
影响因子：
3.8
通讯作者：
Hoelscher, Michael
中科院分区：
文献类型：
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作者：
Heinrich, Norbert;Saathoff, Elmar;Hoelscher, Michael
背景：裂谷热病毒（RVFV）是一种节肢动物传播的静脉病毒。RVFV主要在家养反刍动物中引起暴发，具有重大的经济影响。人类感染与这些事件相关，死亡率为0.5- 2%。由于该病毒是能够使用许多蚊子物种的温带气候作为载体，它有很高的潜力蔓延到African.Methodology/Principal调查结果：我们进行了分层，横断面血清流行率调查，1228名参与者从姆贝亚地区，坦桑尼亚西南部。样本是从2007年和2008年参加队列研究的17，872人中选出的。RVFV IgG状态通过间接免疫荧光测定。采用单变量和多变量Poisson回归模型分析可能的危险因素。我们发现一个独特的地方RVFV IgG流行率最高的29.3%，在马拉维湖附近的一个研究地点（N = 150）。总体血清阳性率为5.2%。血清阳性与较高的年龄，较低的社会经济地位，牛的所有权，并减少与马拉维湖的距离。发现高植被密度、较高的最低温度和较低的最高温度与RVFV IgG阳性相关。居住海拔高度，特别是在高流行区的小范围内，有很强的相关性（PR 0.87每米，95%CI = 0.80-0.94）。在高流行率地点的较低地区存在丰富的地表水收集。裂谷热尚未得到临床诊断，也没有在高流行率area.Conclusions：RVFV可能是在该地区流行的地方性。牛的存在、茂密的植被和温和的条件有利于蚊子的繁殖和病毒在媒介中的复制，似乎在病毒传播和循环中起着重要作用。我们确定的环境风险因素可以更准确地确定RVFV流行的风险地区。
Background: The Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus. RVFV mostly causes outbreaks among domestic ruminants with a major economic impact. Human infections are associated with these events, with a fatality rate of 0.5-2%. Since the virus is able to use many mosquito species of temperate climates as vectors, it has a high potential to spread to outside Africa.Methodology/Principal Findings: We conducted a stratified, cross-sectional sero-prevalence survey in 1228 participants from Mbeya region, southwestern Tanzania. Samples were selected from 17,872 persons who took part in a cohort study in 2007 and 2008. RVFV IgG status was determined by indirect immunofluorescence. Possible risk factors were analyzed using uni-and multi-variable Poisson regression models. We found a unique local maximum of RVFV IgG prevalence of 29.3% in a study site close to Lake Malawi (N = 150). The overall seroprevalence was 5.2%. Seropositivity was significantly associated with higher age, lower socio-economic status, ownership of cattle and decreased with distance to Lake Malawi. A high vegetation density, higher minimum and lower maximum temperatures were found to be associated with RVFV IgG positivity. Altitude of residence, especially on a small scale in the high-prevalence area was strongly correlated (PR 0.87 per meter, 95% CI = 0.80-0.94). Abundant surface water collections are present in the lower areas of the high-prevalence site. RVF has not been diagnosed clinically, nor an outbreak detected in the high-prevalence area.Conclusions: RVFV is probably circulating endemically in the region. The presence of cattle, dense vegetation and temperate conditions favour mosquito propagation and virus replication in the vector and seem to play major roles in virus transmission and circulation. The environmental risk-factors that we identified could serve to more exactly determine areas at risk for RVFV endemicity.