Evaluating the Effects of Climate and Environmental Factors on Under-5 Children Malaria Spatial Distribution Using Generalized Additive Models (GAMs)

Abstract

Malaria disease is majorly caused by the protozoan of the Plasmodium types, which comprise the Plasmodium malariae species, the Plasmodium falciparum species, the Plasmodium ovale species and the Plasmodium vivax species, usually transmitted via the infected female Anopheles mosquitoes [1][2][3][4][5][6].The global burden of the deadly P. falciparum malaria has declined greatly, but the decline has not been universal, and areas of higher burden persist in many African countries [3].According to the 2017 World malaria report, the P. falciparum was the most prevalent species of malaria parasite in the African region, which accounted for approximately 99.8% of the estimated severe malaria cases, followed by the South-Eastern Asia 62.8%, the Eastern Mediterranean 69% and the Western Pacific regions 71.9% [3].From the report, it was also noted that P. vivax was the predominant parasite in the American region.For example, in Venezuela and the Eastern Mediterranean regions, controlling over 70% of all the malaria cases [5-9].However, among the sub-Saharan African countries, Nigeria has the highest share of the global burden of malaria disease [3].More than 95% of the malaria cases in Nigeria are caused by P. falciparum [10][11][12], mostly occurring in children under the age of 5 years [3,10,12].At present almost more than 70% of the Nigerian population live in endemic areas [13,14].An important partway to understanding malaria distribution patterns and planning effective intervention strategies is the identification of important influencing factors to malaria prevalence and transmission [8,15].A challenge in studying malaria risk in Nigeria is the heterogeneity of the prevalence, which is attributed to high variability in climate conditions as well as the landscape [2,16].Few published studies in Nigeria have linked malaria prevalence to several influencing factors, including climate and environmental conditions [2,10,11,13,15,[17][18][19][20], socioeconomic factors [15,[21][22][23], geographical factors [10,[13][14][15]18,24], and control strategies as well as prevalence of other febrile illnesses [22,[25][26][27].Additionally, several authors in other malaria endemic countries have investigated the correlation between malaria and important meteorological variables as observed in Venezuela [6-9], in Zimbabwe [28], in Zambia [29,30], in Côte D'Ivoire [31], in Ghana [32], in Burundi [33], in Ethiopia [34,35] and many more.It was found that malaria

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