Changing Trends in P. falciparum Burden, Immunity, and Disease in Pregnancy.
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 Mozambican 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 reduction 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).


CONCLUSIONS
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 prevalence of malaria. (Funded by Malaria Eradication Scientific Alliance and others.).
From the Barcelona Institute for Global Health (ISGlobal), Barcelona Center for International Health Research (CRESIB), and Hospital Clínic-Universitat de Barcelona (A.M., A.B., A.M.F., R.G., P.C., M.R., J.C., A.J., L.F., J.J.A., C.D., P.L.A., C.M.), Barcelona, and Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBEREsp), Madrid (A.J.) - all in Spain; Centro de Investigação em Saúde da Manhiça (CISM) (A.M., A.B., E.M., T.N., R.G., S. Maculuve, M.R., A.V., B.S., S. Machevo, A. Nhama, L.L., J.J.A., S.A., A. Nhacolo, C.D., E.S., P.L.A., C.M.), Instituto Nacional de Saúde, Ministry of Health (T.N., S. Maculuve, B.S., A. Nhama, S.A.), and Faculdade de Medicina, Universidade Eduardo Mondlane (S. Machevo, E.S.) - all in Maputo, Mozambique; the Graduate Program in Areas of Basic and Applied Biology, Universidade do Porto, Porto, Portugal (A.M.F.); and the International Center for Genetic Engineering and Biotechnology, New Delhi, India (C.C.).
Alfredo
A
Mayor
Azucena
A
Bardají
Eusebio
E
Macete
Tacilta
T
Nhampossa
Ana Maria
AM
Fonseca
Raquel
R
González
Sonia
S
Maculuve
Pau
P
Cisteró
Maria
M
Rupérez
Joe
J
Campo
Anifa
A
Vala
Betuel
B
Sigaúque
Alfons
A
Jiménez
Sonia
S
Machevo
Laura
L
de la Fuente
Abel
A
Nhama
Leopoldina
L
Luis
John J
JJ
Aponte
Sozinho
S
Acácio
Arsenio
A
Nhacolo
Chetan
C
Chitnis
Carlota
C
Dobaño
Esperanza
E
Sevene
Pedro Luis
PL
Alonso
Clara
C
Menéndez
D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood*; D017281:Cost of Illness; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D016778:Malaria, Falciparum / Q000145:classification / Q000453:epidemiology* / Q000276:immunology*; D009073:Mozambique / Q000453:epidemiology; D059208:Parasite Load; D010298:Parity; D010963:Plasmodium falciparum / Q000276:immunology* / Q000302:isolation & purification; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000145:classification / Q000453:epidemiology* / Q000276:immunology; D015995:Prevalence; D012720:Severity of Illness Index; D055815:Young Adult
D000913:Antibodies, Protozoan; D007074:Immunoglobulin G