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Anemia during childhood remains a major public health challenge in sub-Saharan Africa. To determine the prevalence of and the risk factors for anemia in young children, we conducted a longitudinal survey in Ebolowa in southern Cameroon. Children were enrolled in two cohorts and followed during a three-year period : the first cohort was composed of 122 children from 0 to 36 months of age and the second cohort was composed of 84 children from 24 to 60 months of age. The two cohorts were followed weekly for symptomatic malaria, monthly for both symptomatic and asymptomatic malaria, and every six months for hematologic data ; the children were grouped into six-month age groups. The prevalence of anemia (hemoglobin [Hb] level < 11 g/dl) was the highest in the six-month-old age group (47%) and the age-related evolution clearly showed a decrease in the prevalence from three years of age. Thus, 42% of the children less than three years of age were anemic, while 21% of the children between three and five years of age were anemic. The lowest mean + or - SD Hb content (10.7 + or - 2.1 g/dl) was observed in the six-month-old children and a regular improvement in the Hb level occurred from six months to three years of age. A stabilization was observed at a level of approximately 12 g/dl. At any age, there was no difference in mean Hb levels between children with AS and AA Hb genotypes. Hookworm infection was diagnosed in two children in the study population. Results of a multivariate analysis showed that placental malaria infection was the strongest risk factor for anemia in the six-month-old children (odds ratio [OR] = 3.6; 95% confidence interval [CI] = 1.1-12.3) and was independent of the frequency of parasitemia, parasitemia at the time of Hb measurement, or microcytosis... (D'après résumé d'auteur)

Since 1985, chloroquine resistance (CR) became evident in Cameroon, and rapidly spread out over the country. Despite such a situation, chloroquine is still the first antimalarial drug. CR follow up was mostly carried out by in vivo tests among schoolchildren. In this population, of a mean 9 yrs of age, a CR rate of 30 to 45% was reported. However, this may not show the true level of CR, because of the interaction of immunity in controlling parasite growth. Therefore, in southern Cameroon, we studied the activity of 25 mg/kg over 3 days of chloroquine and amodiaquine in treating asymptomatic children ranging from 1 to 15 yrs, with parasite density > 1000/microl. Following chloroquine treatment, children with treatment failure by D7 in the 0-2, 3-4, 5-9 and 10-15 yrs age groups were : 26-37 (71%), 9/21 (43%), 24/43 (56%) and 12/30 (40%). Four infections were RIII, all in the 0-2 yrs group. 41 of the 60 children with a D7 negative blood smear were seen again at D14 : 19 of these (46%) were positive. Following amodiaquine, children with treatment failure by D7 were : 3/28 (11%), 2/20 (10%), 1/17 (6%) and 0/6. No RIII level was observed. 44 of the 65 children with D7 negative blood smear were seen on D14 : 7 (16%) had a positive blood smear, 5 being in the 0-2 yrs group. The prevalence of CR in southern Cameroon is high, especially in young children. The prevalence and level of CR decreased with age. Amodiaquine is effective > 89% in all age groups, and might be considered as a first line treatment in young children. Medical practitioners must be provided with information on resistance within groups having not yet acquired premunition. (Résumé d'auteur)

In areas endemic for malaria, pregnant women frequently present with a placenta that has been parasitized by #Plasmodium falciparum$, an infection associated with a reduction in the birth weight of the offspring. However, the impact of placental infection on malaria-related morbidity during the infant's first year of life has not been investigated. Between 1993 and 1995, 197 children in southern Cameroon were followed weekly clinically and monthly parasitologically. The dates of first positive blood smear and the evolution of the parasite prevalence rates were compared between infants born to mothers presenting with (n = 42) and without (n = 155) #P. falciparum$ infection of the placenta. Infants born to placenta-infected mothers were more likely to develop a malaria infection between 4 and 6 months of age; then the difference progressively disappeared. Similarly, parasite prevalence rates were higher in placenta-infected infants from 5 to 8 months of age. Thus, malarial infection of the placenta seems to result in a higher susceptibility of infants to the parasite. This was not related to maternally transmitted antibodies, as specific antibody levels were similar in both groups of infants. A better understanding of the involved mechanisms may have important implications for the development of malaria control strategies. (Résumé d'auteur)