DOI: http://dx.doi.org/10.18203/2394-6040.ijcmph20195068

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

Alok Kanjhoor Premdas, Binu Areekal, Sudhiraj Thiruthara Sukumaran, Ashwin Raj Kunnumel Kandi

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.


Keywords


Leptospirosis, Trend, Forecast, Meteorological factors, Time series analysis

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References


WHO. Leptospirosis Burden Epidemiology Reference Group (LERG). Available at: https:// www.who.int/zoonoses/diseases/lerg/en/. Accessed on 30 August 2019.

Regional office for South East Asia. Leptospirosis-fact sheet. World health Organisation. Available at: http://www.searo.who.int/about/administration_structure/cds/CDS_leptospirosis-Fact_Sheet.pdf. Accessed on 30 August 2019

Leptospirosis- fact sheet for clinicians. Available at: https://www.cdc.gov/leptospirosis/pdf/fs-leptospirosis-clinicians-eng-508.pdf. Accessed on 30 August 2019.

Leptospirosis: Practice Essentials, Background, Pathophysiology. Available at: https://emedicine. medscape.com/article/220563-overview. Accessed on 30 August 2019.

Joshi YP, Kim EH, Cheong HK. The influence of climatic factors on the development of hemorrhagic fever with renal syndrome and leptospirosis during the peak season in Korea: an ecologic study. BMC Infect Dis. 2017;17:406.

6.4.4.8.1. Box-Ljung Test. Available at: https:// www.itl.nist.gov/div898/handbook/pmc/section4/pmc4481.htm. Accessed on 31 August 2019.

Time Series Model Nugget, 2014. Available at: www.ibm.com/support/knowledgecenter/en/ss3ra7_15.0.0/com.ibm.spss.modeler.help/timeseries_modelnode.htm. Accessed on 31 August 2019.

Director of health services. Public Health. Public health data, DHS Kerala. 2018. Available at: http://dhs.kerala.gov.in/index.php/publichealth.html. Accessed on 30 August 2019.

Sethi S, Sharma N, Kakkar N, Taneja J, Chatterjee SS, Banga SS, et al. Increasing Trends of Leptospirosis in Northern India: A Clinico-Epidemiological Study. PLoS Negl Trop Dis. 2010;4(1):e579.

Pawar SD, Kore M, Athalye A, Thombre PS. Seasonality of leptospirosis and its association with rainfall and humidity in Ratnagiri, Maharashtra. Int J Health Allied Sci. 2018;7(1):37.

Spickler AR, Leedom Larson KR. Leptospirosis.pdf. Technical Factsheets, 2013. Available at: http://www.cfsph.iastate.edu/Factshee ts/pdfs/leptospirosis.pdf. Accessed on 30 August 2019

Ehelepola NDB, Ariyaratne K, Dissanayake WP. The correlation between local weather and leptospirosis incidence in Kandy district, Sri Lanka from 2006 to 2015. Glob Health Action. 2019;12(1):1553283.

Matsushita N, Ng CFS, Kim Y, Suzuki M, Saito N, Ariyoshi K, et al. The non-linear and lagged short-term relationship between rainfall and leptospirosis and the intermediate role of floods in the Philippines. PLoS Negl Trop Dis. 2018;12(4):e0006331.

Pappachan MJ, Sheela M, Aravindan KP. Relation of rainfall pattern and epidemic leptospirosis in the Indian state of Kerala. J Epidemiol Community Health. 2004;58(12):1054.

Chadsuthi S, Modchang C, Lenbury Y, Iamsirithaworn S, Triampo W. Modeling seasonal leptospirosis transmission and its association with rainfall and temperature in Thailand using time-series and ARIMAX analyses. Asian Pacific J Trop Med. 2012;5(7):539-46.