Plasmodium falciparum: sickle-cell trait is associated with higher prevalence of multiple infections in Gabonese children with asymptomatic infections.

Through PCR amplifications of the gene encoding the merozoite surface antigen 2, utilizing allele-specific 3D7 and FC27 probes, we have examined the prevalence of Plasmodium falciparum in children aged from 7 to 14 years living in a village located in the equatorial forest region of Central Africa (Gabon). Using this technique, 61% (100/163) of the blood samples were shown to be infected with P. falciparum with 24 alleles distinguished by size polymorphism and sequence type. The two main families (3D7 and FC27) and hybrid alleles were detected regardless of sex and hemoglobin phenotype. No age-related changes in prevalence of P. falciparum strains were observed; however, the prevalence of infection (42%) was significantly lower in individuals with the sickle-cell trait compared with their normal-hemoglobin counterparts (68%). Mixtures of genetically distinct parasite clones were present in 82% of children carrying the sickle-cell trait but in only 58% of normal-hemoglobin carriers. The significance of these observations regarding the design and interpretation of epidemiological investigations is discussed in the context of malaria transmission in the region studied.

A population-based health survey in Kon Dieng District, Cambodia.

PIP: The survey on immunization, treatment for diarrhea, night blindness, and infant mortality was carried out in April, 1992, using a cluster sample design and systematic random sampling. 30 clusters (villages) were selected from a total of 105, and 25 households with a child less than 5 years old were identified in each cluster. The female head of household was interviewed. A total of 761 households with at least 1 child less than 5 years old were surveyed. There were 4667 persons in the sample: 282 were children less than one year old and 853 were children aged 12-59 months. The mean age of the respondents was 34 +or- 9 years, and 48% could not read. A handicapped person was reported in 14% (106/761) of the households. In children under 10 years of age, mental retardation, polio sequelae, and deafness/hardness of hearing were the leading causes (17/21, 81%) of disability. In children 10-14 years old, deafness/hardness of hearing and partial or complete blindness accounted for 72% (15/21) of the disabilities: 33% of 20-39 years old handicapped adults (14/42) were missing 1 or more limbs and 12% (5/42) suffered from polio sequelae. A child with night blindness was reported in 14% (107/761) of the households. Diarrheal episodes in the 2 weeks before the survey amounted to 578/761 (51%) of children less than 5 years old. Treatment included oral rehydration therapy in 145 (10%), and Western medicine in 702 (49%). 49% of the mothers reported that their child had been immunized. Fully immunized children 9-23 months old numbered 20/134 (6%). Infant mortality rate was 84/1000 live births. 81% of infant deaths occurred within 6 months of birth. Fevers and respiratory distress were reported as the leading causes of death. Improving access to immunization services should be a priority. The high number of night blindness and either partial or complete loss of vision indicate need for vitamin A supplements. In-depth interviews of mothers of recently deceased children could help determine the causes of death, and assist program planners in reducing the high morbidity and mortality in the district.^ieng