Relationships of Schistosoma haematobium, hookworm and malarial infections and metrifonate treatment to growth of Kenyan school children.

Relationships of S. haematobium, hookworm and malarial infections to growth 6 months after metrifonate treatment were studied in Kenyan primary school children in an area where poor growth, S. haematobium and hookworm were common and malaria was endemic. All children with light-moderate S. haematobium infections (1-500 eggs/10 ml adj) in 4 schools were examined (Exam 1), allocated at random to either placebo (MIP, n = 198) or metrifonate treatment (MIT, n = 201) groups, treated, and examined again 6 months later (Exam 2). An additional 19 heavily infected children (HIT group greater than 500 eggs/10 ml adj) were treated immediately after Exam 1 and also followed. The MIT and HIT groups exhibited more rapid growth between Exam 1 and 2 than did the placebo group. The MIT group gained significantly (P less than 0.001) more than the MIP group in weight (0.8 kg), percent weight for age (2.3 percentage points), weight for height squared (0.04 units), arm circumference (0.4 cm), percent arm circumference for age (1.7 percentage points) and in triceps and subscapular skinfold thicknesses. In addition, the placebo group showed statistically significant decreases between exams in percentage weight for age, percent arm circumference for age, both skinfold thicknesses for age and no significant increase in percent height for age while the MIT group exhibited highly significant increases in all anthropometric parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships of Schistosoma hematobium, hookworm and malarial infections and metrifonate treatment to hemoglobin level in Kenyan school children.

Relationships between hemoglobin level and S. hematobium, hookworm, and malarial infection before and six months after metrifonate treatment were studied in Kenyan primary school children in an area where anemia, S. hematobium and hookworm are common (prevalences 61%, 46%, and 95%, respectively) and malaria is holoendemic. The mean hemoglobin level in children from one school, both with and without S. hematobium infection (n = 250), was significantly lower in children with higher S. hematobium egg counts, heavier hookworm infections, positive Plasmodium slides, and larger spleens. All children with light-moderate S. hematobium infection (1-500 eggs/10 ml adj) in four schools were examined (Exam 1), allocated at random to either placebo (MIP, n = 198) or metrifonate treatment (MIT, n = 202) groups, treated, and examined again six months later (Exam 2). Hemoglobin levels rose significantly in both groups between exams, but the rise in the MIT group was 30% higher than in the MIP group (1.3 vs. 1.0 g/dl, P less than 0.014). The increase in hemoglobin level in the MIT group was significantly and positively correlated with decreases between exams in S. hematobium and hookworm egg counts and with higher malarial parasite counts at Exam 1 (Pearson r's 0.21, 0.20, 0.20, respectively, P less than 0.01). A stepwise multiple regression equation using hemoglobin rise between exams as the dependent variable showed that decreases in S. hematobium and hookworm egg counts were equally important determinants of hemoglobin rise and that malarial parasite count was almost as important as the changes in intensities of the helminth infections. These results show that treatment for S. hematobium with metrifonate can increase hemoglobin levels in children in an area where S. hematobium and anemia are common. They also emphasize the importance of measuring multiple parasitic infections and using multivariate statistical techniques such as multiple regression analysis in order to define the relationships between parasitic infections and morbidity.

Urinary iron loss and physical fitness of Kenyan children with urinary schistosomiasis.

Daily urinary iron loss and physical fitness were determined in Kenyan primary school children who had low-medium (16-177 eggs/10 ml adj) or high (200-1,194 eggs/10 ml adj) S. hematobium egg counts compared with a matched group of control or uninfected children before and after antischistosomal treatment with metrifonate. The 3 groups did not differ significantly before treatment in age, sex ratio, anthropometry or prevalence of other parasite infections. Before treatment, mean iron loss in the high egg count group (n = 14) was 652 micrograms/24 hr and was significantly higher than losses in the low-medium and control groups (losses = 278, 149 micrograms; n = 19, 12 respectively). Iron loss in infected children was correlated with egg count (r = 0.40) and log of egg count (r = 0.56, P less than 0.0003). After treatment iron loss decreased in the infected groups and post-treatment iron losses did not differ significantly. Physical fitness scores, measured with the Harvard Step Test, showed that the control group (score 81) was significantly more fit than the high egg count group (score 69) before treatment. Fitness scores improved significantly in both infected groups after treatment, and post-treatment fitness scores did not differ significantly between the 3 groups. This study provides evidence that relatively heavy infections of S. hematobium can cause urinary iron loss which, if it persists, is great enough to produce iron deficiency anemia and can also reduce physical fitness of children, but that both of these negative effects are reversible with treatment.

Regression of splenomegaly and hepatomegaly in children treated for Schistosoma haematobium infection.

During a study in Kenya of the relationships between Schistosoma haematobium infection and anemia and growth, evidence was found to suggest that this infection was associated with splenomegaly in children, and that both splenomegaly and hepatomegaly regressed in children treated for urinary schistosomiasis, compared with a placebo group. These results imply that S. haematobium is partially responsible for the splenomegaly and hepatomegaly found in this malarious area, and that treatment for S. haematobium may cause a significant regression of splenomegaly and hepatomegaly in children.

Sensitivity and specificity of reagent strips in screening of Kenyan children for Schistosoma haematobium infection.

The reliability of using urinalysis reagent strips, which semi-quantitatively measure hematuria and proteinuria, to correctly select urine specimens found by microscopy to have Schistosoma haematobium eggs was studied in 359 previously unscreened Kenyan primary school children. The presence of and degree of hematuria and proteinuria were highly correlated with the presence of S. haematobium eggs and with egg counts in urine specimens. Hematuria was more strongly correlated with S. haematobium egg counts than was proteinuria. The ability of presence of hematuria or proteinuria, or both, to select all microscopically positive cases of urinary schistosomiasis for treatment was tested using sensitivity (ST) and specificity (SP) analysis. Selection of cases using 1) presence of hematuria alone, and 2) presence of either hematuria or proteinuria had the highest combined ST and SP (88% ST, 97% SP; 91% ST, 92% SP, respectively). Most of the few cases detected by microscopy but not by reagent strips had low egg counts. The presence of hematuria alone failed to detect only 12% of S. haematobium-positive cases (mostly low egg counts), and only 3% of S. haematobium-negative persons had urinary blood and would have received unnecessary treatment. Preliminary studies on the use of reagent strips to screen previously infected children 6 months after treatment, and the effects of seasonal variations in temperature and humidity on urine specimen volume, egg counts, and reagent strip results are also presented. The practical field use and cost of reagent strips in S. haematobium control programs are discussed.