No abstract

A randomized, double-blind, placebo-controlled iron supplementation trial was conducted in Kenya to examine the effect of iron supplements on appetite and growth in 87 primary school children. Sustained-release ferrous sulfate (150 mg) or placebo tablets were provided daily at school for 14 wk. Prior to tablet administration, baseline anthropometry, iron nutritional status (hemoglobin and serum ferritin), parasitic infections and clinical indicators of morbidity were measured. A baseline appetite test was conducted twice on each child by quantitatively measuring the ad libitum consumption of a midmorning snack. In addition, each child was asked for a subjective assessment of his or her appetite. Follow-up exams and appetite tests were identical to those at baseline. Findings indicated that provision of iron supplements resulted in improved growth and improved appetite (in terms of both energy intake of the snack and child report of appetite) as compared with children receiving the placebo. The increased energy intake from the snack was 10% of the daily estimated energy intake for children of this same age group living elsewhere in Kenya. Further research into the underlying physiological mechanisms may shed light on the relationship between iron nutritional status and appetite.

We studied growth in infected children given one dose (600 mg) or two doses of albendazole per school year. Children were examined and allocated at random within sex by descending hookworm egg count to one of three groups: placebo (n = 93), one dose (1x, n = 96) or two doses (2x, n = 95). Each child was treated and then re-examined and treated 3.6 and 8.2 mo later (Exams 2 and 3). The 1x and 2x groups gained significantly more by Exam 3 than the placebo group in weight (1.1 and 0.9 kg more, respectively), percent weight-for-age (3.3 and 2.7 percentage points more), percent weight-for-height (3.1 and 2.9 percentage points more), percent arm circumference-for-age (2.3 and 2.0 percentage points more) and triceps and subscapular skinfolds but did not differ significantly from each other. The placebo group showed significant decreases between exams (P < 0.0002) in percent weight-for-age and percent arm circumference-for-age and no change in percent weight-for-height, whereas the 1x and 2x groups exhibited significant increases (P < 0.005). At Exam 3, arithmetic mean egg reduction rates for the 1x and 2x groups were 84 and 95% for hookworm, 42 and 32% for Trichuris and 55 and 87% for Ascaris, respectively. We conclude that one or two doses of albendazole per year resulted in similar growth improvements, despite reinfection, in school-age children in an area where these helminths and poor growth are prevalent.

We studied physical fitness with the Harvard step test (HST), in primary schoolboys infected with hookworm (91% baseline prevalence), Trichuris trichiura (94%) and Ascaris lumbricoides (39-40%) who received a single 400 mg dose of albendazole or an identical placebo. Boys were examined, allocated at random to placebo or albendazole groups, treated, and re-examined 7 weeks later. The 2 groups did not differ significantly before treatment in age, anthropometry, haemoglobin levels, prevalence or intensity of the 3 helminth infections, or in initial HST fitness scores and heart rates. Seven weeks after treatment, the albendazole group (n = 18) exhibited significant improvements in fitness scores and heart rates at 1, 2, 3, and 4 min after the HST while in the placebo group (n = 15) these quantities had not changed significantly. After treatment, the albendazole group had significant decreases in the logarithmic egg counts for hookworm (80% reduction in arithmetic means) and A. lumbricoides (100% reduction); T. trichiura egg counts did not change significantly. The placebo group showed a borderline increase in the logarithms of hookworm egg counts and no significant change in T. trichiura and A. lumbricoides egg counts. Multiple regression analysis showed that the significant linear predictors of increase in HST score after treatment were decrease in resting heart rate after treatment, and decreases in hookworm egg counts and logarithms of A. lumbricoides egg counts after treatment. We conclude that single dose treatment with albendazole, despite continual exposure to reinfection, can allow improved physical fitness in schoolboys in areas where soil-transmitted helminths and protein-energy malnutrition are highly prevalent.

The simultaneous estimation of infection rate, cure rate and detectability of parasitic infections is considered. A new method for this estimation based on a simple statistical model assuming constant transition rates between parasite states is proposed. Repeated observations on the infection status of the same individuals is required for this method. A maximum likelihood approach is used for parameter estimation and the calculation of standard errors of the estimates. The method is illustrated by a longitudinal study of the presence of Giardia lamblia infection in Kenyan children.