Prevalence of malaria in an area receiving seasonal malaria chemoprevention in Niger.

BACKGROUND

Malaria transmission is highly seasonal in Niger. Despite the introduction of seasonal malaria chemoprevention (SMC) in the Magaria District, malaria incidence remains high, and the epidemiology of malaria in the community is not well-understood.

METHODS

Four cross-sectional, household-based malaria prevalence surveys were performed in the Magaria District of Niger between October 2016 and February 2018. Two occurred during the peak malaria season and two during the low malaria season. Individuals in each of three age strata (3-59 months, 5-9 years, and 10 years and above) were sampled in randomly-selected households. Capillary blood was collected by fingerprick, thick and thin blood films were examined. Microscopy was performed at Epicentre, Maradi, Niger, with external quality control. The target sample size was 396 households during the high-season surveys and 266 households during the low-season surveys.

RESULTS

Prevalence of parasitaemia was highest in children aged 5-9 years during all four surveys, ranging between 53.6% (95%CI 48.8-63.6) in February 2018 and 73.2% (66.2-79.2) in September 2017. Prevalence of parasitaemia among children aged 3-59 months ranged between 39.6% (33.2-46.4) in February 2018 and 51.9% (45.1-58.6) in October 2016. Parasite density was highest in children aged 3-59 months during all four surveys, and was higher in high season surveys than in low season surveys among all participants. The prevalence of gametocytaemia in children aged 3-59 months ranged between 9.9% (6.5-14.8) in February 2018 and 19.3% (14.6-25.2) in October 2016. The prevalence of gametocytaemia in children aged 5-9 years ranged between 6.3% (3.5-11.1) in February 2018 and 18.5% (12.7-26.1) in October 2016.

CONCLUSIONS

Asymptomatic malaria infection is highly prevalent in this area, even during the season with low incidence of clinical malaria. The high prevalence of parasitaemia in children aged 5-9 years warrants considering their inclusion in SMC programmes in this context.