Molecular Detection of Malaria at Delivery Reveals a High Frequency of Submicroscopic Infections and Associated Placental Damage in Pregnant Women from Northwest Colombia

Abstract

Abstract. Plasmodium infection in pregnancy causes substantial maternal and infant morbidity and mortality. In Colombia, both P. falciparum and P. vivax are endemic, but the impact of either species on pregnancy is largely unknown in this country. A cross-sectional study was carried out with 96 pregnant women who delivered at their local hospital. Maternal, placental, and cord blood were tested for malaria infection by microscopy and real-time quantitative polymerase chain reaction (qPCR). A high frequency of infection was detected by qPCR (45%). These infections had low concentrations of parasite DNA, and 79% were submicroscopic. Submicroscopic infections were associated with placental villitis and intervillitis. In conclusion, the overall frequency of Plasmodium infection at delivery in Colombia is much higher than previously reported. These data prompt a re-examination of the local epidemiology of malaria using molecular diagnostics to establish the clinical relevance of submicroscopic infections during pregnancy as well as their consequences for mothers and newborns.

Immune responses during gestational malaria: a review of the current knowledge and future trend of research

“…As already mentioned, placental parasitaemia is rarely explored, particularly at early stages, and in regions where P. falciparum is predominant, term pregnancies exhibit higher parasite densities than peripheral blood [37,41]. A similar finding has recently been reported in areas where P. vivax is predominant [42].…”

“…Pregnant women are also more likely to experience relapses than non-pregnant ones [44]. P. vivax sequestration has been proposed [10], and recent reports indicate disproportional organ-specific and peripheral blood parasitaemia [42]. As for the dynamics of infection throughout pregnancy, no studies have addressed the issue.…”

“…Sensitivities of the rapid test for P. vivax were 75,0 (CI 95%; 50.6 -90.4) in the mother, 57,14 (CI 95%; 29.6 -81.2) in placenta and 50,00 (CI 95%; 2.7 -97.3) in cord blood [58]. Finally, recent reports using a quantitative real time PCR technique to establish the diagnosis of infection, confirmed rates of infection of up to 45% by either P. falciparum or P. vivax [42].…”

“…The widespread use of molecular techniques applied to the diagnosis of gestational or placental malaria has resulted in the discovery of a large gap in positivity between microscopic and molecular diagnosis [35,42]. Health authorities remain to address this problem, particularly for endemic settings where most diagnosis is performed in the field.…”

Evaluation of Two Nested PCR-Based Diagnostic Assays for Plasmodium Falciparum Infection

“…PCR has shown to be good alternative methods, because of the high sensitivity and specificity. These methods could be used for identification of malaria parasite and could detect malaria parasites in mixed infections and submicroscopic parasitemia better than microscopic examination and RDTs [19,20]. Nested PCR is considered to be a sensitive and specific method for detecting the malaria parasite, and it is also valuable in epidemiological survey, as previously described [13].…”