Trend of leptospirosis and its association with meteorological factors in Thrissur district, Kerala

Abstract

Background: Leptospirosis is a common zoonosis caused by bacteria, Leptospira. The core determinants of the disease are the presence of carrier animals, environmental factors and the interaction between man, carrier and the environment. Understanding the type of relation between these factors and leptospirosis will help in controlling the disease. The current study intends to find the trend of leptospirosis cases, to forecast the disease and to correlate number of cases of leptospirosis with meteorological factors. Methods: The data of leptospirosis cases and the meteorological factors in Thrissur district were collected and entered in MS-Excel and statistical analysis was done using SPSS-16.0. For analysing the trend and to forecast the same, time series analysis method was used. The correctness of the model was tested using Ljung-Box statistics. Results: Time series chart, autocorrelation and partial autocorrelation show leptospirosis follows a seasonal trend. Forecasting of leptospirosis cases from July 2018 to May 2019 made by the model matched with original number reported in Thrissur district. Cross correlation of total rainfall and total rainy days showed that leptospirosis peak approximately 1 month after the onset or together with the rain (lag-1 and 0, r0.471 and 0.380 for total rainfall, lag-1 and 0, r0.501 and 0.469 for total rainy days). Humidity positively affects number of leptospirosis cases (lag-1 and 0, r0.464 and 0.435). June to October, seasonally adjusted factor (SAF) was >100% with highest SAF in August (202.2%). Conclusions: Leptospirosis shows a seasonal trend with more cases in June to October and correlates with change in meteorological factors of the region.

The interrelationship between meteorological parameters and leptospirosis incidence in Hambantota district, Sri Lanka 2008–2017 and practical implications

“…Our results indicate that this factor plays a lesser role in Hambantota. A study from Thrissur district, Kerala, India with similar high maximum temperatures like Hambantota but also with high rainfall shows that high maximum temperatures have a negative correlation with leptospirosis case numbers [ 44 ]. In Kandy, with an average temperature of 25°C, a rise of temperatures means moving towards the optimum range.…”

Leptospirosis in Si Sa Ket, Thailand: Incidence and Factors of Death during 2010-2019

“…5, October 2021 ISSN 2673-0014 (Online) / © Geoinformatics International 152 Special Issue on HealthGIS 2021 agriculture and peri-domestic animal farming in rural areas can be seen in common in these regions zone (Sanjeewani, 2017). Flooding after rainfall can force humans and rodents into closer contact, which can result in further contamination of surrounding water (Premdas et al, 2019). There were differences from the previous study that flooding had a low influence on leptospirosis infection (Suwanpakdee et al, 2015).…”

“…A study from Malaysia reported that the incidence was continued increasing from 6.99 per 100,000 population in 2010 to 30.20 per 100,000 population in 2015 (Disease Control Division, Ministry of Health, Malaysia, 2015). A study from Thrissur district, Kerala, India which showed the highest cases in 2014 followed by 2016 and the least number of cases was reported in 2017 (Premdas et al, 2019). A study from Mumbai, India reported that the incidence of leptospirosis was rose from 207 cases in 2012 to 512 cases in 2016 (Mavatkar et al, 2017).…”

Effects of Rainfall on Human Leptospirosis in Thailand: Evidence of Multi-Province Study Using Distributed Lag Non-linear Model

“…Agricultural workers are considered the most infected group because their intensive farming activities coincide with rainy season, where pathogenic leptospires in renal tubules of infected animalscan be shed in urine and contaminated in water environment. Some related studies have indicated thatrainfall might serve as an important driverfor human leptospirosis transmission (Lau et al 2010;Mwachui et al 2015;Pappas et al 2008; Victoriano et al 2009), and the association of rainfall with human leptospirosis has been indicated elsewhere, such as in Brazil (Hacker et al 2020), China (Dhewantara et al 2019), the Philippines (Matsushita et al 2018), Sri Lanka (Robertson et al 2012) andIndia (Premdas et al 2019). In Thailand, human leptospirosis is endemic and becomes epidemic following heavy rainfall and ooding events (Altheimer et al 2020;Chadsuthi et al 2017;Gonwong et al 2017).…”