Wednesday, 01/29/2014 · CRESIB Seminars

Alfredo Mayor


Fall and rise of malaria among Mozambican pregnant women and its relationship with antimalarial immunity and the complexity of infections

Aula 3, Faculty of Medicine
Malaria resurgence is a major concern after elimination of the parasite, as changes in the epidemiology and waning of host immunity could potentially exacerbate the adverse impact of malaria rebounds. The aim of this presentation is present our investigation on how changes in malaria prevalence among Mozambican pregnant women can impact antimalarial immunity, complexity of infections and pregnancy outcomes. To address this, P. falciparum infection by microscopy, histology and qPCR was compared among 1815 women participating in intermittent preventive treatment trials conducted between 2003 and 2012 in Manhiça, Mozambique. Antibody responses against a CSA-binding and a rosetting parasite line, as well as VAR2CSA, sporozoite and merozoite recombinant antigens, were measured by flow cytometry and multiplex suspension array technology. Complexity of P. falciparum infections were assessed through msp1 and msp2 genotyping. We show how declines in malaria prevalence in pregnancy from 2003 to 2010 and subsequent increases until 2012 were mirrored by antibody levels against VAR2CSA, suggesting that measurement of these antibodies may be useful to estimate changes in the intensity of malaria transmission during elimination activities. The reduction of malaria prevalence was accompanied by increases in the frequency of single clone infections, parasite densities and reductions of haemoglobin levels in those women still infected. Waning of immunity against P. falciparum in pregnancy after only 5 years of a continued declining transmission could increase the risk of malaria-related serious adverse effects in potential resurgences of malaria.