Placental malaria. II. A semi‐quantitative investigation of the pathological features

Abstract

Malaria in pregnancy is associated with reduced birth weight. Most pathological studies of placental malaria infection have focused on severe Plasmodium falciparum infection. In the present study of 121 placentas delivered in a rural area of The Gambia, malaria infection was diagnosed in tissue sections using a simple classification system and severity of pathology was ranked semiquantitatively. Deposition of malaria pigment in circulating cells was associated with active infections whereas pigment in fibrin was a feature of active-chronic infections. Primigravidae had higher levels of pigment at all sites, although these observations were not always significant. Thickening of the trophoblast basement membrane occurred in all infection categories but fibrinoid necrosis of chorionic villi was a feature of active and active-chronic infection. Both birth weight and placental weight were increased in infected placentas but widespread trophoblast basement membrane thickening was associated with decreased birth weight. Both birth weight and placental weight decreased with increased fibrinoid necrosis and cytotrophoblast prominence but the results were not significant. By this approach it has been possible to correlate placental pathology with different infection categories and to analyse the pathological features associated with decreased birth weight.

Diagnosis of Gestational, Congenital, and Placental Malaria in Colombia: Comparison of the Efficacy of Microscopy, Nested Polymerase Chain Reaction, and Histopathology

“…The placental histopathology classification had four categories: 1) acute infection, 2) chronic infection, 3) past infection, and 4) uninfected. 19,20 Operational and costs assessment. Information on sev eral aspects concerning this evaluation was recorded on a precoded form.…”

“…This enables classification of the placental tissue into acute active infection (presence of parasites with pigment scarce or absent), chronic active infection (presence of parasites and pigment relatively abundant), or past infection (exclusive presence of pigment) depending on the inflammatory process. 19,20 Additional classifications of placental malaria include aspects such as the analysis of infiltrating inflammatory cells. 21 A review of the performance of LM, RDTs, and PCR to diagnose maternal and placental P. falciparum infection concluded that, in eight African countries, the mean sensitivities of these methods to detect maternal infection were 21.2%, 29.2%, and 49.6%, respectively, and the ratio of infections detected by PCR versus microscopy was 3.3:1.…”

Impaired uteroplacental blood flow in pregnancies complicated by falciparum malaria

“…All placental biopsies were assessed for evidence of malaria infection by two investigators (E.D. and J.B.) in the UK, blind to any clinical information 20,21 . In cases where classification differed (37/332, 11.1%) the slides were re-read and consensus reached.…”

Placental Malaria in Colombia: Histopathologic Findings in Plasmodium vivax and P. falciparum Infections

“…The placental intervillous space is the area where most placental malariaassociated injuries occur. In the case of P. falciparum, specific changes in the placenta are evident, 11,[18][19][20][21][22][23][24][25][26] including hemozoin deposition, which might have an interesting role in the pathogenesis of gestational malaria or placental malaria.…”