Polymerase chain reaction (PCR)-based methods were used to investigate malaria in pregnant women residing in Yaounde, Cameroon. Microscopy and species-specific PCR-based diagnosis show that at delivery 82.4% of the women were infected with Plasmodium falciparum (27.5% blood-smear positive and 54.9% submicroscopic infections). The prevalence of P. malariae and P. ovale was 7.6% and 2.5%, respectively, with 9.4% infected with more than one species. Based on genotyping of the merozoite surface protein 1 (msp-1) and msp-2 alleles, the mean number of genetically different P. falciparum parasites in peripheral blood was 3.4 (range = 1-9) and 3.5 (range 1-8) in the placenta. Plasmodium falciparum detected by microscopy and PCR as well as mixed-species infections were significantly higher in women < or = 20 years old and paucigravidae, but maternal anemia was associated only with microscopic detection of parasites. Neither submicroscopic infections nor number of parasite genotypes decreased significantly with age or gravidity. Thus, pregnancy-associated immunity helps reduce malaria to submicroscopic levels, but does not reduce the number of circulating parasite genotypes.

Abstract. In support of ongoing immunologic studies on immunity to Plasmodium falciparum, demographic, entomologic, parasitologic, and clinical studies were conducted in two Cameroonian villages located 3 km apart. Simbok (population ϭ 907) has pools of water present year round that provide breeding sites for Anopheles gambiae, whereas Etoa (population ϭ 485) has swampy areas that dry up annually in which A. funestus breed. Results showed that individuals in Simbok receive an estimated 1.9 and 1.2 infectious bites per night in the wet and dry season, respectively, whereas individuals in Etoa receive 2.4 and 0.4 infectious bites per night, respectively. Although transmission patterns differ, the rate of acquisition of immunity to malaria appears to be similar in both villages. A prevalence of 50-75% was found in children Ͻ 10 years old, variable levels in children 11-15 years old, and 31% in adults. Thus, as reported in other parts of Africa, individuals exposed to continuous transmission of P. falciparum slowly acquired significant, but not complete, immunity.

Rubella virus (RV) infection is responsible of an unresolved clinical complication that affects newborns and children. During the first trimester of pregnancy, it often causes severe birth defects known as congenital rubella syndrome (CRS). This study reports the seroprevalence of the RV-specific IgM and IgG antibodies, its relationship with the duration of pregnancy and past history of abortion in pregnant women at Yaoundé in order to help strategies to eliminate rubella and to prevent Congenital Rubella Syndrome (CRS) in Cameroon. Four Hundred (400) pregnant women were screened for rubella immunoglobulins G (IgG) and M (IgM), using the chemiluminescent microparticle immunoassay for the detection of IgG and IgM antibodies on the ARCHITECT i system at the Laboratory of Medical Analysis of Pasteur Institute, Senegal. Out of the400 pregnant women tested, 367 (91.75%) were positive for RV-IgG while only 5 (1.25%) were positive for RV-IgM. A higher number of pregnant women in the first trimester of pregnancy tested positive for IgG (91.8%). None of the possible risk factors were significantly associated with infection. The presence of rubella RV-IgM and RV-IgG in pregnant women predisposes babies to CRS and emphasizes on the initiation of a vaccination policy of those who are susceptible in Cameroon.