The Teaching (General) Hospital-Peradeniya, Peradeniya, Sri Lanka.
Lanka Hydraulic Institute, Moratuwa, Sri Lanka.
PLoS One. 2021 Jan 22;16(1):e0245366. doi: 10.1371/journal.pone.0245366. eCollection 2021.
Leptospirosis is a bacterial zoonosis. Leptospirosis incidence (LI) in Sri Lanka is high. Infected animals pass leptospires to the environment with their urine. Leprospires' survival in the environment to infect a new host depends on meteorological factors. El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) modulate the weather in Sri Lanka.
The determination of interrelationship between the LI in the Hambantota District, and local meteorological parameters, ENSO and IOD.
We acquired notified leptospirosis cases in the Hambantota District and population data. We calculated weekly leptospirosis incidences for 2008 to 2017.Weather data from two weather stations was obtained, averaged and converted into weekly data. We plotted time series graphs and observed the correlation between seven aggregated weather parameters and LI. We estimated cross-correlations between those weather parameters and LI. As our principal analysis we determined correlation between LI and seven local weather parameters, Nino 3.4, Nino4 and Dipole Mode Index (DMI) indices using wavelet analysis.
Our wavelet analysis results showed troughs of minimum, maximum, mean temperatures, soil temperature, the evaporation rate, the duration of sunshine were followed by peaks in LI and peaks of rainfall followed by peaks of LI, all after lag periods. Our time series graphs and cross-correlation determination results are generally in agreement with these results. However there was no significant correlation between rainfall and LI in the cross-correlation analysis. There were peaks of LI following both peaks and troughs of DMI. There was no clear correlation between both Nino indices and LI.
This may be the first long-term study demonstrating soil temperature, evaporation rate and IOD are correlating with LI. The correlation pattern of LI with temperature parameters differs from similar past studies and we explain the reasons. We propose ways to control high LI we observed after periods of weather favorable for transmission of leptospirosis.
钩端螺旋体病是一种细菌性人畜共患病。斯里兰卡的钩端螺旋体病发病率（LI）很高。受感染的动物会随尿液将钩端螺旋体传染给环境。钩端螺旋体在环境中存活以感染新宿主取决于气象因素。厄尔尼诺-南方涛动（ENSO）和印度洋偶极子（IOD）调节斯里兰卡的天气。
确定汉班托塔区的 LI 与当地气象参数、ENSO 和 IOD 之间的相互关系。
我们获得了汉班托塔区报告的钩端螺旋体病病例和人口数据。我们计算了 2008 年至 2017 年的每周钩端螺旋体病发病率。从两个气象站获得了天气数据，取平均值并转换为每周数据。我们绘制了时间序列图，观察了七种综合气象参数与 LI 之间的相关性。我们估计了这些气象参数与 LI 之间的交叉相关性。作为我们的主要分析，我们使用小波分析确定了 LI 与七个当地气象参数、Nino 3.4、Nino4 和偶极子模式指数（DMI）指数之间的相关性。
我们的小波分析结果表明，最低、最高、平均温度、土壤温度、蒸发率、日照时间的波谷之后是 LI 的波峰，降雨的波峰之后是 LI 的波峰，所有这些都有滞后期。我们的时间序列图和交叉相关确定结果通常与这些结果一致。然而，在交叉相关分析中，降雨量与 LI 之间没有显著相关性。LI 之后有 DMI 的波峰和波谷。两个 Nino 指数与 LI 之间没有明显的相关性。
这可能是第一项长期研究表明土壤温度、蒸发率和 IOD 与 LI 相关。LI 与温度参数的相关模式与类似的过去研究不同，我们解释了原因。我们提出了在有利于钩端螺旋体传播的天气过后控制我们观察到的高 LI 的方法。
