Impact of human immunodeficiency virus infection on Streptococcus pneumoniae colonization and seroepidemiology among Zambian women.

Nasopharyngeal colonization with Streptococcus pneumoniae precedes invasive pneumococcal disease. Human immunodeficiency virus (HIV) infection increases rates of invasive pneumococcal disease, and its effect on colonization is unknown. In a longitudinal cohort of Zambian mothers with or without HIV infection, HIV infection increased the risk of colonization (risk ratio [RR], 1.9; 95% confidence interval [CI], 1.3-2.8) and repeat colonization (RR, 2.4; 95% CI, 1.1-5.3) and reduced the time to new colonization (P = .01). Repeat colonization with homologous sero/factor types occurred only among HIV-positive mothers. Pediatric serotypes 6, 19, and 23 accounted for excess colonization among HIV-positive mothers. HIV infection significantly increases the risk of pneumococcal colonization. Increased rates of colonization by pediatric serotypes suggest a potential role for the 7-valent pneumococcal vaccine in HIV-infected adults.

Effect of presumptive co-trimoxazole prophylaxis on pneumococcal colonization rates, seroepidemiology and antibiotic resistance in Zambian infants: a longitudinal cohort study.

OBJECTIVE: To ascertain the microbiological consequences of WHO's recommendation for presumptive co-trimoxazole prophylaxis for infants with perinatal HIV exposure. METHODS: Using a longitudinal cohort design, we followed HIV-exposed and HIV-unexposed infants trimonthly for up to 18 months per infant. HIV-exposed infants received daily co-trimoxazole prophylaxis from 6 weeks to > or = 12 months of age. Using Streptococcus pneumoniae as our sentinel pathogen, we measured how co-trimoxazole altered nasopharyngeal colonization, pneumococcal resistance to antibiotics and serotype distribution as a function of co-trimoxazole exposure. FINDINGS: From 260 infants followed for 3096 patient-months, we detected pneumococci in 360/1394 (25.8%) samples. HIV-exposed infants were colonized more frequently than HIV-unexposed infants (risk ratio, RR: 1.4; 95% confidence interval, CI: 1.0-1.9, P = 0.04). Co-trimoxazole prophylaxis reduced colonization by ca 7% but increased the risk of colonization with co-trimoxazole-resistant pneumococci within 6 weeks of starting prophylaxis (RR: 3.2; 95% CI: 1.3-7.8, P = 0.04). Prophylaxis with co-trimoxazole led to a small but statistically significant increase of nasopharyngeal colonization with pneumococci not susceptible to clindamycin (RR: 1.6; 95% CI: 1.0-2.6, P = 0.04) but did not increase the risk of non-susceptibility to penicillin (RR: 1.1; 95% CI: 0.7-1.7), erythromycin (RR: 1.0; 95% CI: 0.6-1.7), tetracycline (RR: 0.9; 95% CI: 0.6-1.5) or chloramphenicol (RR: 0.8; 95% CI: 0.3-2.3). Co-trimoxazole prophylaxis did not cause the prevailing pneumococcal serotypes to differ from those that are targeted by the 7-valent conjugate pneumococcal vaccine (RR: 1.0; 95% CI: 0.7-1.6). CONCLUSION: Co-trimoxazole prophylaxis modestly suppresses pneumococcal colonization but accelerates infant acquisition of co-trimoxazole- and clindamycin-resistant pneumococci. Co-trimoxazole prophylaxis appears unlikely to compromise the future efficacy of conjugate vaccines.

Inferiority of single-dose sulfadoxine-pyrimethamine intermittent preventive therapy for malaria during pregnancy among HIV-positive Zambian women.

BACKGROUND: The World Health Organization advocates 2-3 doses of sulfadoxine-pyrimethamine (SP) for intermittent preventive treatment of malaria (SP IPTp). The optimal number of doses and the consequences of single-dose therapy remain unclear. METHODS: Data were from a randomized, controlled study of human immunodeficiency virus-positive Zambian women comparing monthly versus 2-dose SP IPTp. We compared maternal and neonatal birth outcomes as a function of how many doses the mothers received (1 to > or =4 doses). RESULTS: Of 387 deliveries, 34 received 1 dose of SP. Single-dose SP was significantly associated with higher proportions of maternal anemia, peripheral and cord blood parasitemia, infant prematurity, and low birth weight. SP conferred dose-dependent benefits, particularly in the transition from 1 to 2 doses of SP. Women randomized to the standard 2-dose regimen were much more likely to receive only 1 dose than were women randomized to monthly IPT (relative risk, 16.4 [95% confidence interval, 4.0-68.3]). CONCLUSIONS: Single-dose SP was a common result of trying to implement the standard 2-dose regimen and was inferior to all other dosing regimens. At a programmatic level, this implies that monthly SP IPTp may ultimately be more effective than the standard regimen by reducing the risk of inadvertently underdosing mothers.

Age, temperature, and parasitaemia predict chloroquine treatment failure and anaemia in children with uncomplicated Plasmodium falciparum malaria.

The prevalence of chloroquine-resistant Plasmodium falciparum malaria has been increasing in sub-Saharan Africa and parts of South America over the last 2 decades, and has been associated with increased anaemia-associated morbidity and higher mortality rates. Prospectively collected clinical and parasitological data from a multicentre study of 788 children aged 6-59 months with uncomplicated P. falciparum malaria were analysed in order to identify risk factors for chloroquine treatment failure and to assess its impact on anaemia after therapy. The proportion of chloroquine treatment failures (combined early and late treatment failures) was higher in the central-eastern African countries (Tanzania, 53%; Uganda, 80%; Zambia, 57%) and Ecuador (54%) than in Ghana (36%). Using logistic regression, predictors of early treatment failure included younger age, higher baseline temperature, and greater levels of parasitaemia. We conclude that younger age, higher initial temperature, and higher baseline parasitaemia predict early treatment failure and a higher probability of worsening anaemia between admission and days 7 or 14 post-treatment.

Severe linear growth retardation in rural Zambian children: the influence of biological variables.

BACKGROUND: The prevalence of stunting in preschool children in Zambia is high; stunting has detrimental effects on concurrent psychomotor development and later working capacity. OBJECTIVE: Our objective was to investigate biological variables that may contribute to linear growth retardation in preschool children in Samfya District, Zambia. DESIGN: Children aged 6-9 mo (n = 108) and 14-20 mo (n = 102) attending mother-and-child health clinics were included. With a mixed-longitudinal design, they were followed up 9 and 21 mo later. Height and weight of children and their mothers were measured. Biochemical measures (eg, serum zinc, retinol, thyrotropin, iron, and acute phase protein concentrations), malaria parasitemia, and intestinal parasitosis were assessed. RESULTS: Height-for-age z scores (HAZ) were low, indicating a high prevalence of stunting (36-79%). Ninety percent of the children were anemic, 53-71% had elevated acute phase proteins, and 80% had malaria parasitemia. Regression analyses showed that maternal height predicted the children's height at 6-9 mo (regression coefficient = 0.05; 95% CI: 0.02, 0.08). The children's height at an early age (6-9 and 14-20 mo) showed a strong relation with their height at later ages (22-30 and 34-41 mo). Serum micronutrient status did not show a significant relation with later HAZ. CONCLUSION: Unlike other studies, we did not identify specific biological factors, such as health and micronutrient status, which contribute to the retardation of linear growth. The normal zinc and iodine statuses of the children suggest that at least these factors are not causal.

Mixed Plasmodium infection in rural children of Zambia.

A total of 210 blood slides from rural children in Samfya District were examined for malaria parasites. One hundred and seventy two were positive for malaria parasites giving a prevalence of 819 pc. Among the children less than one year of age, the prevalence of mixed Plasmodium infection was 124 pc. For children one year and above, the prevalence of mixed Plasmodium infection was 227 pc. There was a statistically significant difference between these two prevalence rates of mixed Plasmodium infection.