Determinants of infant susceptibility to malaria during the first year of life in South Western cameroon

Abstract

Background. Falciparum malaria is an important pediatric infectious disease that frequently affects pregnant women and alters infant morbidity. However, the impact of some prenatal and perinatal risk factors such as season and intermittent preventive treatment during pregnancy (IPTp) on neonatal susceptibility has not been fully elucidated. Methods. A cohort of 415 infants born to women who were positive and negative for malaria was monitored in a longitudinal study in Southwestern Cameroon. The clinical and malaria statuses were assessed throughout, whereas paired maternal-cord and 1-year-old antimalarial antibodies were assayed by enzyme-linked immunosorbent assay. Infant susceptibility to malaria was ascertained after accounting for IPTp and season in the statistical analysis. Results. Malaria prevalence was higher in women (P = .039) who delivered during the rainy season and their infants (P = .030) compared with their dry season counterparts. Infants born to women who were positive for malaria (6.40 ± 2.83 months) were older (P = .028) than their counterparts who were negative for malaria (5.52 ± 2.85 months) when they experienced their first malaria episode. Infants born in September-November (adjusted odds ratio [OR] = 0.31, 95% confidence interval [CI] = 0.13-0.72) and to mothers on 1 or no IPTp-sulfadoxine/pyrimethamine (SP) dose (adjusted OR = 0.51, 95% CI = 0.28-0.91) were protected, whereas those born in the rainy season (adjusted OR = 2.82, 95% CI = 1.21-6.55) were susceptible to malaria. Conclusions. Intermittent preventive treatment during pregnancy and month of birth have important implications for infant susceptibility to malaria, with 2 or more IPTp-SP dosage possibly reducing immunoglobulin M production.

Keywords: IPTp; antibodies; infant susceptibility; malaria; pregnancy; season.

Figure 1.

Relative morbidity of 283 infants from Mutengene, South Western Cameroon within the first year of life. Asymptomatic parasitemia was only assessed during the quarterly surveys, whereas fever and malaria episodes were recorded throughout the morbidity visits to the health center.

Figure 2.

Plasmodium falciparum-specific immunoglobulin (Ig)G, IgG1–4, IgE, and IgM optical densities (OD) and seropositivity in malaria-exposed and unexposed pregnant women and their offspring from South Western Cameroon. A, maternal blood; B, cord blood; C, 1-year-old children.