IN AFRICA’s Rift Valley, there can be up to 32 000 flies in any given home on
a given day—too many for swatting, and more than enough to spread disease.
But a bit of low-tech fiddling with a couple of old plastic pop bottles and some
animal dung has led to the development of an effective fly trap that is helping
control the world’s second leading cause of blindness.
About 14 million people worldwide suffer from trachoma, a bacterial infection
that is spread in part by flies and inflames the eye, filling it with sticky
mucus. Over years, multiple…
