A case-crossover analysis of the impact of weather on primary cases of Middle East respiratory syndrome
A case-crossover analysis of the impact of weather on primary cases of Middle East respiratory syndrome
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DOI：
10.1186/s12879-019-3729-5
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发表时间：
2019-02-04
影响因子：
3.7
通讯作者：
Greer, Amy L.
中科院分区：
文献类型：
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作者：
Gardner, Emma G.;Kelton, David;Greer, Amy L.
中东呼吸综合征冠状病毒（MERS-CoV）是阿拉伯半岛单峰骆驼的地方性流行病，人畜共患传染给人是偶发事件。在缺乏关于宿主物种的流行病学数据的情况下，人畜共患传染病的传播模式基本上是根据主要人间病例估计的。本研究的目的是确定气象因素，可能会增加原发性MERS infections in human.MethodsA病例交叉设计的风险，以确定在2周的潜伏期内，在沙特阿拉伯使用单变量条件Logistic回归原发性MERS病例和先前的天气条件之间的关联。2015年1月至2017年12月期间出现症状的病例来自世界卫生组织维护的公开可用的人类MERS病例行列表。减少完整病例数据集（N=1191），以近似最可能代表骆驼溢出传播的病例（N=446）。利用每个省最大城市附近气象站的数据计算日平均、最低和最高温度（C）、相对湿度（%）、风速（m/s）和能见度（m）。天气变量进行了分类，根据地层，温度和湿度成三分位数，能见度和风速成half.ResultsLowest温度（比值比=1.27; 95%CI =1.04-1.56）和湿度（OR=1.35; 95%CI =1.10-1.65）与8- 10天后的病例增加。高能见度与7天后病例数增加有关（OR=1.26; 95%CI =1.01-1.57），而风速也与5- 6天后的病例数呈统计学显著相关。结论结果表明，沙特阿拉伯的原发性MERS人间病例更有可能在条件相对寒冷和干燥时发生。这与温带气候中其他呼吸道疾病的季节性模式相似。据推测，低能见度将与MERS的原发病例呈正相关，但观察到相反的关系。这可能反映了不同天气条件下的行为变化。这项分析提供了关键的初步证据，表明环境因素有助于原发性MERS-CoV感染的发展。
BackgroundMiddle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedary camels in the Arabian Peninsula, and zoonotic transmission to people is a sporadic event. In the absence of epidemiological data on the reservoir species, patterns of zoonotic transmission have largely been approximated from primary human cases. This study aimed to identify meteorological factors that may increase the risk of primary MERS infections in humans.MethodsA case-crossover design was used to identify associations between primary MERS cases and preceding weather conditions within the 2-week incubation period in Saudi Arabia using univariable conditional logistic regression. Cases with symptom onset between January 2015 - December 2017 were obtained from a publicly available line list of human MERS cases maintained by the World Health Organization. The complete case dataset (N=1191) was reduced to approximate the cases most likely to represent spillover transmission from camels (N=446). Data from meteorological stations closest to the largest city in each province were used to calculate the daily mean, minimum, and maximum temperature (C), relative humidity (%), wind speed (m/s), and visibility (m). Weather variables were categorized according to strata; temperature and humidity into tertiles, and visibility and wind speed into halves.ResultsLowest temperature (Odds Ratio=1.27; 95% Confidence Interval=1.04-1.56) and humidity (OR=1.35; 95% CI=1.10-1.65) were associated with increased cases 8-10days later. High visibility was associated with an increased number of cases 7days later (OR=1.26; 95% CI=1.01-1.57), while wind speed also showed statistically significant associations with cases 5-6days later.ConclusionsResults suggest that primary MERS human cases in Saudi Arabia are more likely to occur when conditions are relatively cold and dry. This is similar to seasonal patterns that have been described for other respiratory diseases in temperate climates. It was hypothesized that low visibility would be positively associated with primary cases of MERS, however the opposite relationship was seen. This may reflect behavioural changes in different weather conditions. This analysis provides key initial evidence of an environmental component contributing to the development of primary MERS-CoV infections.