Malaria in East African highlands during the past 30 years: impact of environmental changes

Abstract

East African highlands are one of the most populated regions in Africa. The population densities in the highlands ranged between 158 persons/km2 in Ethiopia and 410 persons/km2 in Rwanda. According to the United Nations Population Fund, the region has the world's highest population growth rate. These factors are likely behind the high rates of poverty among the populations. As there were no employment opportunities other than agricultural, this demographic pressure of poor populations have included in an extensive unprecedented land use and land cover changes such as modification of bushland, woodland, and grassland on hillsides to farmland and transformation of papyrus swamps in valley bottoms to dairy pastures and cropland and changing of fallows on hillsides from short or seasonal to longer or perennial. Areas harvested for food crops were therefore increased by more than 100% in most of the highlands. The lost of forest areas, mainly due to subsistence agriculture, between 1990 and 2010 ranged between 8000 ha in Rwanda and 2,838,000 ha in Ethiopia. These unmitigated environmental changes in the highlands led to rise temperature and optimizing the spread and survival of malaria vectors and development of malaria parasites. Malaria in highlands was initially governed by low ambient temperature, trend of malaria transmission was therefore increased and several epidemics were observed in late 1980s and early 2000s. Although, malaria is decreasing through intensified interventions since mid 2000s onwards, these environmental changes might expose population in the highlands of east Africa to an increase risk of malaria and its epidemic particularly if the current interventions are not sustained.

Tree-Based Ecosystem Approaches (TBEAs) as Multi-Functional Land Management Strategies—Evidence from Rwanda

“…The region's land resources and diverse ecosystems have chronically faced rising population pressures. The population in the region has doubled over the last 30 years [3]; during 2000-2016 the region recorded population growth of 3% per year, exceeding that of the world (1.2%) and even of the SSA average (2.7%) [1]. The population in the region is further projected to grow at the fastest pace in the world by 2050 [1,4].…”

To what extent does climate explain variations in reported malaria cases in early 20th century Uganda?

“…The southwestern part of the country was a particular focus ( Figure 1) as its high altitude implies increased sensitivity to variations in temperature. As a consequence, this area of the country in particular has received much attention in the past, including recent debate on the potential impact of climate change on malaria in eastern Africa (Steyn, 1946;Garnham et al, 1948;De Zulueta et al, 1961, 1964Lindsay and Martens, 1998;Mouchet et al, 1998;Kilian et al, 1999;Lindblade et al, 1999Lindblade et al, , 2000Cox et al, 2007;Wandiga et al, 2010;Himeidan and Kweka, 2012).…”

Effect of Deforestation and Land Use Changes on Mosquito Productivity and Development in Western Kenya Highlands: Implication for Malaria Risk

“…Several postulates have been put forward to explain increase in malaria epidemics in high altitude areas: land use changes (4, 9, 10), changes in climate (4, 19), and demographic patterns (5, 17). Land cover changes have been suggested to cause increased risks of malaria transmission in high altitude areas in several parts of the world (9, 10, 12, 20).…”