title: Intestinal helminthiasis in children of early primary school going age in north-eastern peninsular Malaysia: The effects of the infection on intestinal permeability, occult colonic blood loss growth and school attendance rates
Creators: name: Mahendra Raj, Sundramoorthy
Publisher: name: University of Glasgow
Year: 1999
Subjects: subject: Epidemiology, parasitology.

description: Ascaris lumbricoides and Trichuris trichiura are the two predominant intestinal helminth infections in North-eastern peninsular Malaysia. This thesis is a contribution towards evaluating the effects of the infections on children of early primary school going age in the area. The effect on small intestinal mucosal integrity as measured by the lactulose/mannitol differential permeability test was determined in a study of 246 children from two schools, 106 of whom were infected with intestinal helminths (Chapter 3). Intestinal permeability was assessed on all children at baseline and infected children were treated with albendazole. Permeability studies were then repeated on the infected children and on 68 uninfected subjects, 6-8 weeks after intervention. Infected and uninfected groups were compared with respect to baseline permeability, change in permeability after treatment, the correlation between baseline worm intensity and baseline permeability as well as the correlation between the fall in worm intensity and change in permeability. Analysis of the data suggested that helminthiasis has a marginal effect on intestinal permeability, the impact of which on children of lower socioeconomic groups was negligible in comparison with the cumulative effects of other potentially noxious factors. The availability of accurate school attendance registers was exploited to simultaneously study the effect of helminthiasis on school attendance in the above group (Chapter 6). Ascariasis was associated with absenteeism at one of the schools but treatment did not improve the attendance rates in comparison with a control group of Ascaris negative children. The study did not provide any evidence that helminthiasis independently affected school attendance rates. Overt rectal bleeding is part of the Trichuris Dysentery syndrome; a rare complication of trichuriasis. The possibility that trichuriasis causes occult colonic bleeding in the absence of the overt Trichuris Dysentery syndrome was explored in a study conducted on another cohort of 104 schoolchildren; 61 of whom harboured Trichuris worms (Chapter 4). A commercially available guaiac test kit was used to detect occult blood in the faeces of all 104 children. To increase the chances of detecting occult bleeding, additional serial testing was conducted on the 11 children who had heavy trichuriasis and 8 uninfected controls. Although the initial design allowed for repeat stool occult blood testing after treatment, the baseline results obviated the need for this. There was no evidence that trichuriasis predisposes to occult colonic bleeding in the absence of the overt dysenteric syndrome. The children who took part in the occult blood loss study were also the subjects of a simultaneous investigation on the effect of intestinal helminthiasis on growth (Chapter 5). The overall helminth positive rate in this cohort was 70%. Height and weight measurements were taken at baseline and 14 weeks after antihelminthic treatment. The increases in height, weight, weight for age, height for age and weight for height were greater among infected children who were treated than uninfected controls despite the fact that infected children were on average drawn from lower socioeconomic backgrounds. The gains were modest but statistically significant and occurred predominantly in girls. Although the independent effects of treating Ascaris and Trichuris infections on growth were difficult to determine with certainty because of the high prevalence of mixed infections, the trends did suggest that successful treatment of trichuriasis may be the critical factor in promoting growth. The suggestion that helminthiasis in North-eastern Peninsular Malaysia adversely affects growth among early primary schoolchildren requires validation by further interventional studies utilising regimes with greater efficacy particularly against trichuriasis. Investigation of the effect of Trichuris infection on colonic mucosal integrity may shed further light on the question of whether modest burdens of Trichuris infection are indeed detrimental to health. In conclusion, the results suggest that intestinal helminthiasis among young primary school children in North-eastern Peninsular Malaysia, has a modest independent effect on growth and a marginal effect on intestinal permeability (the impact of which on children from lower socioeconomic backgrounds is negligible); but does not independently cause school absenteeism nor occult colonic bleeding.