Abstract:
BACKGROUND
Prevention of reinfection and resurgence is an integral component of the goal to
eradicate malaria. However, the adverse effects of malaria resurgences are not
known.
METHODS
We assessed the prevalence of Plasmodium falciparum infection among 1819 Mozam-
bican women who delivered infants between 2003 and 2012. We used microscopic
and histologic examination and a quantitative polymerase-chain-reaction (qPCR)
assay, as well as flow-cytometric analysis of IgG antibody responses against two
parasite lines.
RESULTS
Positive qPCR tests for P. falciparum decreased from 33% in 2003 to 2% in 2010 and
increased to 6% in 2012, with antimalarial IgG antibody responses mirroring these
trends. Parasite densities in peripheral blood on qPCR assay were higher in 2010–
2012 (geometric mean [±SD], 409±1569 genomes per microliter) than in 2003–2005
(44±169 genomes per microliter, P = 0.02), as were parasite densities in placental
blood on histologic assessment (50±39% of infected erythrocytes vs. 4±6%, P<0.001).
The malaria-associated reduction in maternal hemoglobin levels was larger in
2010–2012 (10.1±1.8 g per deciliter in infected women vs. 10.9±1.7 g per deciliter in
uninfected women; mean difference, −0.82 g per deciliter; 95% confidence interval
[CI], −1.39 to −0.25) than in 2003–2005 (10.5±1.1 g per deciliter vs. 10.6±1.5 g per
deciliter; difference, −0.12 g per deciliter; 95% CI, −0.67 to 0.43), as was the reduc-
tion in birth weight (2863±440 g in women with past or chronic infections vs.
3070±482 g in uninfected women in 2010–2012; mean difference, −164.5 g; 95%
CI, −289.7 to −39.4; and 2994±487 g vs. 3117±455 g in 2003–2005; difference,
−44.8 g; 95% CI, −139.1 to 49.5).ONCLUSIONS
Antimalarial antibodies were reduced and the adverse consequences of P. falciparum
infections were increased in pregnant women after 5 years of a decline in the preva-
lence of malaria. (Funded by Malaria Eradication Scientific Alliance and others.)
