Spatio-Temporal Analysis of Malaria in Paraguay

Master’s Thesis, University of Nebraska, May 2011

Nicole Wayant

“Malaria is a mosquito-borne disease that has afflicted humans for thousands of years.  Today it is considered a re-emerging disease.  Malaria is most prevalent in tropical and subtropical parts of the world.  The disease has been linked to several environmental parameters, including precipitation, temperature, and deforestation.  However, these relationships have mainly been studied in Africa and have not been explored in other parts of the world.  The study area for this thesis was the South American country of Paraguay.

“Paraguay has experienced an oscillation in malaria cases over the past 20 years, with monthly cases ranging from 0 to 1200.  Additionally, the country has experienced vast amounts of deforestation and climate variations.  The thesis study area was two Paraguayan departments, Alto Parana and Canindeyú.  Both departments had a record of monthly malaria cases for the years of 1981-2003.

“It was discovered that there was a positive correlation between malaria and temperature and vegetation strength and a negative correlation between precipitation and malaria.  Spatial comparisons of deforestation maps and maps of malaria risk based on the selected environmental parameters, suggests recent deforestation increases the probably of malaria occurrence.  Additionally, time series analysis provides evidence that an increase in temperature increases malaria cases every 2-3 years.  The annual oscillation of temperature, precipitation, and vegetation change from the wet and dry seasons corresponds with the low and high activity time periods for malaria case rates.”