Background: Several studies have shown that the risk of malaria infection increases for children born to a mother with placental malaria infection. An immune tolerance phenomenon has been hypothesized. We addressed whether Plasmodium falciparum placental infection could additionally be associated with the risk of nonmalaria fevers in infants.
Methods: From 2007 to 2009, 553 infants were followed up from birth to 18 months in Benin. The occurrence of fever was actively screened by trained community workers. Malaria fevers (temperature >37.5°C with positive results of rapid diagnostic test or thick blood smear) were excluded from analysis. The association between placental malaria infection and the number of total, gastrointestinal, and respiratory febrile episodes was explored using binomial negative regression, with adjustment for maternal age, parity, parents' schooling, socioeconomic level, sex, village of birth, season of birth, prematurity, Apgar score and nutritional status.
Results: The prevalence of placental malaria infection was 11.2%. During a median follow-up of 17.8 months, 624 nonmalaria fevers were registered. Placental malaria infection was associated with a higher risk of nonmalaria fever episodes (adjusted incidence rate ratio, 1.4; 95% confidence interval, 1.1-1.8) as well as gastrointestinal (1.6; 1.1-2.5) and respiratory (1.5; 1.1-2.1) febrile syndromes. The same pattern was obtained when considering consultations after the age of 6 months.
Conclusions: These results suggest an association between placental malaria infection and nonmalaria infections in the first 18 months of life. Immune tolerance could lead to impaired immune development not specific to malaria infections in infants born to mothers with placental malaria infection, but further studies are needed.