Category Archives: Mapping

High Resolution Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control

Mufaro Kanyangarara and her PhD thesis adviser, Luke Mullany of the Johns Hopkins Bloomberg School of Public Health Department of International Health, have been looking into the challenges of controlling and evCategorical maps of predicted household malaria risk and uncertaintyentually eliminating malaria in a multi-country context in southern Africa. We are sharing abstracts from her pioneering work including the following which explores high resolution risk mapping in Zimbabwe near the Mozambique border.

Background: In Zimbabwe, more than half of malaria cases are concentrated in Manicaland province, where malaria continues to rebound despite intensified control strategies. The objectives of this study were to develop a prediction model based on high-resolution environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province.

Methods: Household RDT status was obtained from ongoing community-based surveys in Mutasa District from October 2012 through April 2015. While environmental variables were extracted from remote sensing data sources and linked to household RDT status. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates. Model prediction performance and overall model fit were examined. Model predictions and prediction standard errors were generated and inverse distance weighting was used to generate smoothed maps of malaria risk and prediction uncertainty by season.

Results: Between October 2012 and April 2015, 398 households participated in the household surveys. Ninety-six individuals representing 66 households tested RDT positive. Household malaria risk was significantly higher among households sampled during the rainy season and further from the Mozambique border, while malaria risk was lower in sparsely populated areas as well as households located at higher elevations during the rainy season. The resulting maps predicted elevated risk during the rainy season particularly in low-lying areas bordering with Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria scattered along the northern, western and south-eastern peripheries of the study area.

Conclusion: This study provides evidence for the significant heterogeneity of malaria, which was strongly linked to elevation, house density and proximity to the Mozambique border. These findings underscore the need for strong cross-border malaria control initiatives to complement country specific interventions.

Satellite Mapping, an important step toward malaria control and elimination in Nigeria

Omede Ogu of Nigeria’s Federal Ministry of Health reports on efforts to undertake mapping of malaria in the country as a basis for better planning of control and eventual elimination efforts.

surface water 1The National Malaria Elimination Program (NMEP) has been meeting with the team from the National Space Research and Development Agency (NASRDA). Progress on pilot malaria mapping in Niger State is being reviewed, though the study is yet to be concluded. NMEP is also looking at opportunities that exist to expand their initial mapping to cover the whole of the country. Discussions are underway on next steps and development of a road map or a framework for the study going forward.

NASRDA explained that the current mapping effort was aimed is to use satellite-based technology to map surface water for Malaria Control in North-central Nigeria with Niger State as a Pilot study. They noted that data in inaccessible locations such as the marshy areas, thick forests, rugged terrain etc. were previously unavailable for relevant environmental policy and decision making in the region and Nigeria.

In addition is will be possible to do infrastructural mapping and inventory of health care facilities, in order to identify and assess the state of health care facilities, how accessible and future areas of need provision of these facilities in the country.

So far NASRDA has identified settlements, and locations of hospitals and health centres throughout Niger State using Global Positioning System (GPS). They have also identified water bodies and wetlands locations throughout the state.

Finally they are developing a map of Surface Water and wetlands in the state showing these in relation to locations of settlements, hospitals and health centres. NMEP is planning to link with colleagues doing similar mapping in Kenya.

NMEP plans to have the final report of the study ready by October for dissemination. Major partners with funding lines in their 2014 work plans for this study are the National Primary Health Care Development Agency (NPHCDA) and NASRDA. Additional funding and support is being sought.

Kenya already is using its mapping to focus appropriate malaria interventions. All countries will benefit in better mapping for targeting their malaria control and elimination efforts.