Department of Clinical Microbiology, Christian Medical College, Vellore, India.
Department of Medicine, Christian Medical College, Vellore, India.
Sci Rep. 2024 Jan 17;14(1):1532. doi: 10.1038/s41598-023-49333-5.
Climate is one of the major factors determining the prevalence and seasonality of vector borne diseases like scrub typhus (ST). We analyzed, the association of the meteorological factors like temperature, rainfall and humidity with scrub typhus using the 15 years scrub typhus data from a tertiary care hospital in Vellore, South India. Demographic data of permanent residents of Vellore, who had IgM ELISA results for scrub typhus for the time period of May 2005 to April 2020 were included. Meteorological data was correlated with the monthly scrub typhus cases; negative binomial regression model was used to predict the relation between scrub typhus occurrence and climate factors. Maximum number of ST cases were reported between the months August and February with October recording the highest number of cases. Elderly people, farmers, agricultural workers and housewives were at higher risk for scrub typhus. For an increase of 1 °C in mean temperature, the monthly ST cases reduced by 18.8% (95% CI - 24.1, - 13.2%). On the contrary, for 1 percent increase in mean relative humidity (RH), there is an increase of 7.6% (95% CI 5.4, 9.9%) of monthly ST cases. Similarly, an increase of 1 mm of rainfall contributed to 0.5 to 0.7% of monthly ST cases (after 2 months) depending on the variables included in the analysis. This study provides information that meteorological factors influence ST occurrence in Vellore. The rise of scrub typhus cases is maximal 2 months post rainfall. Whereas a rise in relative humidity, causes a rise in scrub typhus cases in same month, while rise in temperature has a negative impact on scrub typhus during the same month. These findings based on a retrospective analysis need validation by prospective studies.
气候是决定恙虫病（ST）等虫媒病流行和季节性的主要因素之一。我们分析了印度南部维洛尔的一家三级保健医院 15 年来恙虫病数据中温度、降雨量和湿度等气象因素与恙虫病之间的关联。包括 2005 年 5 月至 2020 年 4 月期间 IgM ELISA 结果为恙虫病的常住居民的人口统计学数据。气象数据与每月恙虫病病例相关联；使用负二项回归模型预测恙虫病发生与气候因素之间的关系。ST 病例报告数量最多的月份是 8 月至 2 月，10 月报告的病例数最多。老年人、农民、农业工人和家庭主妇患恙虫病的风险更高。平均气温每升高 1°C，每月 ST 病例减少 18.8%（95%CI-24.1，-13.2%）。相反，平均相对湿度（RH）每增加 1%，每月 ST 病例增加 7.6%（95%CI 5.4，9.9%）。同样，降雨量增加 1 毫米，每月 ST 病例增加 0.5%至 0.7%（取决于分析中包含的变量），需要 2 个月的时间。本研究提供了气象因素影响维洛尔 ST 发生的信息。降雨后 2 个月 ST 病例上升最多。而相对湿度的上升会导致当月恙虫病病例的上升，而温度的上升则会对当月的恙虫病产生负面影响。这些基于回顾性分析的发现需要前瞻性研究来验证。
