Impact of environment on malaria transmission in a malaria-endemic rural area of Sri Lanka

What is it about?

This study tried to explain the environment-malaria relationship in Sri Lanka spanning a 16-year period. Kataragama, the study area, was previously home to higher malaria cases in the country, however Sri Lanka, now, is malaria-free. We collected monthly malaria case data and environment variables including rainfall, temperature, relative humidity and river flow rate for the period 1990-2005, and used the wavelet technique, a widely used mathematical tool to explain infectious disease transmission cycles under the influence of various factors. We found cyclic patterns of malaria cases in certain time periods from 1992-95 and 1999-2000. We also found that low temperature and river flow rate and higher rainfall and relative humidity have contributed to increased malaria cases in Kataragama during 1991 to 1995, but not during 1999 to 2001.

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Photo by Syed Ali on Unsplash

Photo by Syed Ali on Unsplash

Why is it important?

This study is important for two main reasons. One is spanning out a 16-year study period by covering high malaria endemic period through pre-elimination phase to elimination phase of the malaria elimination programme. Malaria in Sri Lanka has a history of re-emergence following almost successful eradication efforts. Therefore studying malaria for an extended period of time is a timely requirement, to make valid conclusions. Second, of the various mathematical and statistical models and time-series approaches, we used wavelet technique to explain the environment-malaria relationship. We believe that this is the first study that used wavelet technique, to the best of our knowledge, to examine the interaction between environment variables and malaria.

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