Admission to medical schools in Sri Lanka: predictive validity of selection criteria.

OBJECTIVE: To assess the extent to which current selection criteria predict success in Sri Lanka's medical schools. METHODS: The study sample consisted of all students selected to all six medical schools in two consecutive entry cohorts. The aggregate marks of these students at the General Certificate of Education (GCE) Advanced Level examination, the district of entry, admission category, candidate type (school/private) and gender, were identified as entry point variables. Success in medical school was measured in four ways: the ability to pass the first summative examination and the final examination at the first attempt, and obtaining honours in either examination. Multivariate analysis using logistic regression was used to assess the extent to which these entry point factors predict variability in outcome measures. RESULTS: Aggregate scores among the 1740 students in the study sample ranged from 212 to 356, with a median of 285. The male:female ratio was 1.4:1. Private candidates (taking the examination for the third time) accounted for 22% of students. Being a school candidate, female and having a higher aggregate score, were the only independent predictors of success for all four outcome measures. The aggregate score alone accounted for only 1-7% of the variation in performance in medical school. CONCLUSIONS: Marks obtained at the A Level examination (the only academic criterion currently used for selection of medical students in Sri Lanka) is a poor predictor of success in medical school.

Soil contamination with geohelminth ova in a tea plantation.

OBJECTIVE: To determine the degree of soil pollution in an area of high prevalence and the risk of exposure to geohelminth infection. DESIGN: A cross-sectional study. SETTING: A division of a large tea plantation in Kandy. SUBJECTS: All persons resident in one division of the tea plantation, above the age of 1 year. MEASUREMENTS: Prevalence of geohelminth infection measured by microscopic examination of faeces of the study group. Soil samples from 38 specific locations, obtained on 3 different occasions, about 6 months apart, analysed for helminth ova. The average temperature, rainfall and the number of rainy days during the sampling period. RESULTS: Of the 99 subjects of the study group, 77.7% were positive for at least one geohelminth infection. The prevalence rates for ascariasis, trichuriasis and hookworm infection were 54%, 28%, and 22% respectively. At the first sampling, 10.5% of the soil samples were positive for helminth ova with 7.8% and 2.6% samples showing Ascaris and Necator ova respectively. At the second sampling of the same locations nearly 40% of the samples were positive for helminth ova with 21.6%, 7.8% and 10.5% of the samples positive for Ascaris, Trichuris and Toxocara ova respectively. At the third sampling, 26.2% of the samples were positive with 21%, 2.6% and 2.6% of the samples positive for Ascaris, Trichuris and Toxocara ova respectively. Necator ova were found only once in 2.6% of the samples of the first sampling. The larger number of samples positive for helminth ova were in the second and the third samplings which coincided with high rainfall in the pre-sampling period. CONCLUSIONS: The prevalence of geohelminthiases among the study group was high. Results of soil analysis confirmed continued contamination of soil in and around the home gardens and the work areas with human and dog faeces. With the knowledge of exact locations of soil pollution it was possible to advice the management on remedial measures.

Adult filarial worm (Wuchereria bancrofti) in a benign ovarian tumour.

A case of an adult filarial worm (Wuchereria bancrofti) associated with a benign ovarian tumour and a cyst is presented. Possible reasons for the findings of a well preserved part of the worm and a foreign body granuloma in the lymphatic subendothelium are discussed.

Myiasis due to Cardylobia anthropophaga, the 'Tumbu fly' in a Sri Lankan infant.

A case of myiasis due to Cardylobia anthropophaga (Blanchard) (Diptera: Calliphoridae), the 'Tumbu fly', is reported for the first time in Sri Lanka, in a 10 month old infant. The infection was acquired in Zimbabwe. The child had appeared 'unwell' for nearly a week before the detection of the skin lesions. The main clinical features were irritability, restlessness and the appearance of three small lumps on the scalp behind the right ear. Identification of the fly larva and the management of myiasis are discussed.

Effectiveness of mass treatment with mebendazole in the control of soil transmitted helminths in Sri Lanka.

The efficacy of a single large dose of mebendazole was compared with the three-day multiple dose in mass treatment. The subjects were selected from among plantation workers of a tea estate in Kandy. The multiple dose regime showed consistently better egg reduction rates and cure rates when compared to the single large dose in subjects harbouring one or more soil-transmitted helminths.