Application of Remotely-sensed Data for Modeling Malaria Infection in Lokoja, Nigeria

Abstract

Aims: To estimate incidences of malaria infection in an urban setting using Remotely sensed data and matching same with hospital records to validate the use of Remote sensing data as a methodology for studying the prevalence of malaria. Study Design: Analyses of 2006 Nigeriasat-1 and Land sat ETM+satellite data for modeling malaria infection. Place and Duration of Study: Lokoja, Capital city of Kogi State in Central Nigeria, between March 2012 and January 2013. Methodology: Extraction of land use types, NDVI and LST maps using ILWIS 3.3 and Idrisi software. Cross tabulation of extracted maps to carry out correlational analyses while buffer analysis was conducted to ascertain risk zones of malaria infection in the town. The clinical data was used in determining the recorded incidence of malaria in the study area. Results: Built-up area, sand bars and vacant land occupy least land cover (i.e. 28.31%) while urban agricultural land, vegetation and water bodies covered 344.33km2 (59.72%), 41.98km2 (7.28%) and 18.51km2 (3.21%), respectively. The LSE value ranges from 0.92 to 0.989 with an average of 0.955 whereas the highest emissivity is recorded where vegetation is very dense and the lowest recorded for Sand bars. The LST for sand bars, vacant land and built-up area recorded the highest average temperatures of 41.13°C, 35.66°C and 34.56°C, respectively. The highest negative correlation was found in vegetation (-0.96) with other negative values recorded for urban agricultural land and water bodies. The lowest correlation (0.65) was recorded from areas covered with sand bars. The UHI map shows that temperatures at the periphery are lower (about 18°C) but higher at the core (from 26°C to 40°C). Conclusion: The interplay of NDVI, LST and land use/cover types of Lokoja provides the impetus for the rising incidence of malaria in Lokoja town. Proper urban planning which will support sufficient drainages, effective waste removal, sanitary landfill sites, vegetation control, fumigation, etc. can boost sanitary conditions whilst minimizing the availability of breeding sites for mosquito larvae. At the household levels, extensive use of bed nets and periodic fumigation appear to be the most appropriate short-term measures for curtailing the incidences of malaria at the study area.