After 6 months she was referred to the maternity hospital find more because of treatment-resistant anemia (Hb 72 g/L). Tests for hemolysis were positive with Hb 68 g/L at its lowest. A rapid diagnostic test was positive for P falciparum, and the laboratory reported a parasitemia of <0.2% in blood smear (pregnancy week 25+). The diagnosis was also confirmed by polymerase chain reaction (PCR). The patient was treated with a combination of oral quinine and clindamycin for 10 days after which her anemia

subsided. The fourth patient was a 26-year-old woman who had immigrated to Finland in April 2011 from Kenya, where she had been treated for malaria in January the same year. Three months after immigration, with pregnancy week 22+, she was admitted to the maternity hospital because of high C-reactive protein and abdominal discomfort. A diagnosis of anemia (Hb 101 g/L) was established, a rapid test for malaria Inhibitor Library high throughput proved positive, and a smear revealed a parasitemia of 1.6%. The patient was treated with a combination of oral quinine and clindamycin for 10 days, and remained well after that. In areas where malaria is highly endemic, particularly

in sub-Saharan Africa, constant exposure to the parasite results in a gradual development of immunity starting from early childhood.[1] While severe malaria mostly occurs in children, adults usually get a mild or asymptomatic disease and parasitemia may persist for long periods of time, often unnoticed.[1] In areas where malaria is mainly present during epidemics, such as India, P-type ATPase the exposure to malaria parasites is not frequent enough to elicit similar immunity, and all age-groups are at risk of severe malaria.[2] Pregnant women differ from other patient groups. Even in highly endemic areas, immunity fails to protect women during pregnancy, as P falciparum parasites sequestering in the placenta start to express novel types of antigenic structures not covered by the pre-existing immunity.[3] Moreover, high

numbers of parasites may be present in the placenta even when the peripheral blood malaria smear remains negative or shows only low numbers of parasites.[4, 5] This implies that pregnant women, particularly during their first pregnancy, are at increased risk.[6] During subsequent pregnancies, the immune system will have adapted to the new types of antigens associated with placental sequestration, which will reduce the risk of severe disease.[7] Asymptomatic malaria is quite common among immigrants from highly endemic areas.[8-10] According to various reports, the prevalence of persistent parasitemia among refugees varies from 3% to >60%.[10] While the majority remains asymptomatic,[11] the parasitemia may last for years.[12] There is also a risk of symptomatic malaria in pregnant women; cases have been reported over 3 years after immigration.[12] Persistent parasitemia poses a health risk for both the mother and the unborn child.