Swiftlet farming can be a health hazard

I REFER to ‘Heritage states in danger’ (The Star, Feb 24), and am concerned over the conversion of heritage buildings for swiftlet breeding.

Just to obtain the World Heritage site by Unesco, states have to meet various criteria and exhibit an important interchange of human values, over a span of time or within a cultural area of the world, on developments in architecture, technology, monumental art, town-planning or landscape design.