Ministry of Health, 385, Ven. Baddegama Wimalawansa Thero Mawatha, Colombo, 10, Sri Lanka. chinthaj@yahoo.com. Centre for Health Science, University of the Highland and Islands, Old Perth Road, Inverness, IV2 3JH, UK. Centre for Rural Health, University of Aberdeen, Old Perth Road, Inverness, IV2 3JH, UK.