Malaria in Pregnant Cameroonian Women: The Effect of Age and Gravidity on Submicroscopic and Mixed-Species Infections and Multiple Parasite Genotypes

Abstract

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.

Evaluation of oxidative stress and antioxidant status of pregnant women suffering from malaria in Cameroon

“…young mothers are at greater risk of malaria and its adverse effects than older primigravidae or multigravidae, respectively) (15). This suggest that in addition to the parity-specific immunity that is acquired through consecutive pregnancies, age-associated immunity also plays an important role in controlling the infection during pregnancy in areas of high and stable transmission (6). The pronounced enzymatic activity of SOD in pregnant women suffering from malaria make us speculate that patients still in beginning of stress.…”

“…This is attributable to the mosquito vectors of tropical Africa, which probably constitute the most powerful vectorial system anywhere available to malaria parasite. As in many other malaria-endemic regions of sub-Saharan Africa, the most vulnerable groups are children under five-years of age and pregnant women (5,6). An estimated 25 million women become pregnant in malaria-endemic areas of sub-Saharan Africa, with over 10,000 maternal and about 200,000 infant deaths per year as a result of P. falciparum infection (7,8).…”

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

“…Health authorities remain to address this problem, particularly for endemic settings where most diagnosis is performed in the field. The situation has been reported in moderate and highly endemic regions [42,[131][132][133]. In the reports available, submicroscopic infection by P. falciparum is common.…”

Isolation and Characterization of the MSP1 Genes from Plasmodium malariae and Plasmodium ovale

“…The incidence of P. falciparum, P. malariae , and P. ovale infection, as determined by polymerase chain reaction (PCR), in asymptomatic pregnant women from Cameroon was reported to be 91.8%, 7.6%, and 2.5%, respectively. 20 In the current study, whole blood samples from Cameroon blood donors infected with P. malariae or P. ovale were identified. The MSP1 genes from these two species were isolated and characterized, and their deduced protein sequences compared with those of other Plasmodium species.…”