Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Morbidity and mortality due to ascariasis: re-estimation and sensitiviey analysis of global numbers at risk(Blackwell Scientific Publications, 1997) de Silva, N.R.; Chan, M.S.; Bundy, D.A.P.This paper presents estimates of the global numbers of people at risk from morbidity related to infection with Ascaris lumbricoides and the numbers of deaths from this infection. Morbidity is classified into 4 types: deficits in growth and fitness which are contemporaneous with infection, or permanent, overt acute illness of mild to moderate severity, and complications involving hospitalization. The estimation of morbidity is based on theoretical models of parasite distributions developed in previous papers. A sensitivity analysis is carried out in which parameters of the model are varied using a Latin hypercube sampling technique. The results estimate approximately 1300 million infections globally with 59 million at risk of some morbidity. The estimate for acute illness is 12 million cases per year with approximately 10,000 deaths. Most morbidity is in children. Sensitivity analysis suggests that infection estimates will not vary greatly with changes in parameter values but that morbidity estimates may be highly variable.Item Morbidity and mortality due to Ascaris-induced intestinal obstruction(Oxford University Press, 1997) de Silva, N.R.; Guyatt, H.L.; Bundy, D.A.P.We examined epidemiological aspects of Ascaris-induced intestinal obstruction (AI-IO) through analysis of published reports on the subject. In 9 studies of > or = 100 patients admitted to hospital due to ascariasis, intestinal obstruction was the single most common complication and accounted for 38-87.5% of all complications (weighted mean 72%). The proportion of intestinal obstruction caused by ascariasis was identified in 14 studies from 7 countries with varying degrees of endemic ascariasis. Using relevant data on the duration of the study, the number of beds in the reporting hospital, and the number of hospital beds/1000 population in the area, the number of cases of AI-IO/year/1000 population was estimated from 11 studies. Both the proportion of AI-IO (range 0-0.71) and the number of cases of AI-IO/year/1000 population (range 0-0.25) were significantly related, in a non-linear manner, to the local prevalence of ascariasis (range 0.01-0.92). In 12 studies of > or = 30 patients with AI-IO, the case fatality rates ranged from 0 to 8.6% (weighted mean 5.7%). The mean age of patients with AI-IO was < or = 5 years in 6 of 7 studies in which age was specified.Item Socioeconomic and behavioural factors affecting the prevalence of geohelminths in preschool children(SEAMEO Regional Tropical Medicine and Public Health Project, 1996) de Silva, N.R.; Jayapani, V.P.P.; de Silva, H.J.The aim of this study was to examine the relationship between the prevalence of geohelminth infections in preschool children living in an urban slum area in Sri Lanka and parental education, socioeconomic status, the use of anthelmintics, and beliefs regarding these helminths. Between October 1992 and February 1993, stool samples were collected from preschool children (less or equal 60 months of age) in the Mahaiyyawa area, Kandy, Sri Lanka, and examined using direct smears and a concentration technique. Stool samples which were found to be positive for helminth ova were also examined using the modified Kato-Katz technique. A pretested questionnaire was administered to the mothers or principal caretakers of the children from whom stool samples were obtained to assess parental education, socioeconomic status of the family and knowledge, attitudes and practices related to intestinal parasites, particularly geohelminths. Stool samples from 307 children were examined; 81 (26.4 percent) were positive for geohelminth ova. Roundworm infections predominated, and were seen in 73 of the 81 (90.1 percent), either alone or together with whipworm and/ or hookworm infections. All infections were of mild to moderate intensity. Questionnaires were administered to the mothers/principal caretakers of 208 children. Mothers/caretakers of 91 children (45 percent) claimed that the child was on regular anthelmintics. As the educational level of the mother/caretaker improved, the prevalence of geohelminth infections in the children declined (chi-square for linear trend equal 8.19, p equal 0.004). However, there was no significant correlation between prevalence of infections and paternal educational levels. Prevalence also tended to increase as the socioeconomic class declined (chi-square for linear trend equal 4.899, p equal 0.026). Another finding of note in this study was the widespread ignorance and misconceptions regarding geohelminth infections among carers.