b Pregnant women are highly susceptible to malaria infection because of their low immunity and are at increased risk of maternal illness or death, in addition to spontaneous abortion, stillbirth, premature delivery, and low birth weight. However, the detailed pathogenesis of maternal malaria remains unclear. In this study, we evaluated a mouse model that shows similar severe pathological features of pregnant women during Plasmodium falciparum infection and investigated the pathogenesis of maternal malaria. Pregnant mice immunized by infection with an attenuated parasite, Plasmodium berghei XAT, were more susceptible to virulent P. berghei NK65 challenge/infection than were nonpregnant mice and showed high levels of parasitemia and a poor pregnancy outcome associated with placental pathology, such as accumulation of parasitized red blood cells, in the late phase of pregnancy. Notably, the pregnant immune mice challenged/infected with P. berghei NK65 developed liver injury associated with microvesicular fatty infiltration in late pregnancy. The pathological features were similar to acute fatty liver of pregnancy. Higher levels of gamma interferon and nitric oxide (NO) were found in plasma from pregnant immune mice infected with P. berghei NK65 than in plasma from nonpregnant mice. These findings suggest that development of liver injury and placental pathology in pregnant immune mice challenged/infected with P. berghei NK65 is accompanied by enhanced production of proinflammatory cytokines.
Malaria is the most devastating parasitic disease of humans in tropical and subtropical regions, resulting in an estimated 0.6 to 1 million deaths per year (1). The populations at greatest risk of developing severe pathology are children under the age of 5 years and pregnant women in areas where Plasmodium falciparum is endemic (2-4). Every year, approximately 50 million women living in areas where malaria is endemic become pregnant. An estimated 10,000 of these women and 200,000 of their fetuses or infants die annually as a result of malaria during pregnancy (1, 2). Malaria during pregnancy is a major public health problem in areas of endemicity, especially in Africa.People living in regions where malaria is endemic acquire protective immunity against malaria parasites and often show asymptomatic infection. However, women are highly susceptible to malaria infection because of their low immunity during pregnancy and are at increased risk of maternal illness or death (5, 6). Malaria during pregnancy, in addition to maternal illness or death, is implicated in the occurrence of spontaneous abortion, stillbirth, premature delivery, and low birth weight (6). Recently, it has been demonstrated that pregnant mice infected with lethal Plasmodium berghei parasites show a feature similar to placental pathology and subsequently poor pregnancy outcome (7,8).Cerebral malaria (CM) or respiratory distress syndrome has been reported to be an infrequent but relevant cause of maternal death in women living in an area of sub-Saharan Africa where m...