Declines in Malaria Burden and All-Cause Child Mortality following Increases in Control Interventions in Senegal, 2005-2010.

Julie Thwing,Jacques Andre Ndione,Mame Birame Diouf,Yazoume Yé,Roger Tine,Demba Anta Dione,Medoune Ndiop,Moustapha Cisse,Mady Ba,Adama Faye,Erin Eckert

doi:10.4269/ajtmh.16-0953

Abstract

.Malaria is endemic in Senegal. The national malaria control strategy focuses on achieving universal coverage for major interventions, with a goal of reaching preelimination status by 2018. Senegal began distribution of insecticide-treated nets (ITNs) and introduced artemisinin-based combination therapy in 2006, then introduced rapid diagnostic tests in 2007. We evaluated the impact of these efforts using a plausibility design based on malaria’s contribution to all-cause under-five mortality (ACCM) and considering other contextual factors which may influence ACCM. Between 2005 and 2010, household ownership of ITNs increased from 20% to 63%, and the proportion of people sleeping under an ITN the night prior to the survey increased from 6% to 29%. Malaria parasite prevalence declined from 6% to 3% from 2008 to 2010 among children under five. Some nonmalaria indicators of child health improved, for example, increase of complete vaccination coverage from 58% to 64%; however, nutritional indicators deteriorated, with an increase in stunting from 16% to 26%. Although economic indicators improved, environmental conditions favored an increase in malaria transmission. ACCM decreased 40% between 2005 and 2010, from 121 (95% confidence interval [CI] 113–129) to 72 (95% CI 66–77) per 1,000, and declines were greater among age groups, epidemiologic zones, and wealth quintiles most at risk for malaria. After considering coverage of malaria interventions, trends in malaria morbidity, effects of contextual factors, and trends in ACCM, it is plausible that malaria control interventions contributed to a reduction in malaria mortality and to the impressive gains in child survival in Senegal.

Highlights

Malaria is endemic throughout Senegal, where 100% of the population is at risk of infection, and has historically been a leading cause of morbidity and mortality across the country
Results stratified by socioeconomic quintile and epidemiologic zone showed that increases in insecticide-treated nets (ITNs) ownership were greatest among the poorest quintiles and in the highest transmission zones (Figure 3)
The increase in ITN household ownership and population access was accompanied by an increase in the proportion of the population sleeping under an ITN

Summary

Introduction

Malaria is endemic throughout Senegal, where 100% of the population is at risk of infection, and has historically been a leading cause of morbidity and mortality across the country. Senegal is split into four malaria epidemiological zones based on parasite prevalence. Malaria epidemiological zones are characterized by very low transmission in the north, low transmission in the center, and moderate transmission in the south (Figure 1). Dakar, malaria transmission is very heterogeneous, representing a separate epidemiological zone. According to routine data collected by the National Malaria Control Program (NMCP) in 2010, annual incidence of confirmed malaria cases reported by health facilities ranged from less than 5/1,000 persons in the Sahelian north to greater than 100/1,000 persons in the more tropical southeast. Plasmodium falciparum is the major malaria parasite species, accounting for 99% of all infections, with Plasmodium malariae and Plasmodium ovale making up the remaining 1%. The main vector species are Anopheles gambiae s.s., Anopheles arabiensis, Anopheles funestus, and Anopheles melas, depending on rainfall and the presence of permanent sources of water

Methods

Results

Conclusion