A global attack on long-neglected tropical diseases is succeeding

THE story begins with a mosquito bite. As the bloodsucker feeds on a human, in some parts of the world there is the chance it will transmit the larvae of worms which cause a disease called lymphatic filariasis (sometimes known as elephantiasis). After many such bites, the larvae develop into thin microscopic worms which invade the host’s lymphatic system, where they grow into adult worms. During their seven-year lives these worms damage the lymphatic system, and cause infections that lead to blockages, swelling and fevers.

Upendo Mwingira, a programme manager at the ministry of health in Tanzania, sees patients with grossly swollen legs that are painful and disabling. Male victims can develop scrotums so large that they can descend to the knees. Their enlarged limbs may smell foul, as they become prone to infections. They may be shunned by their communities and often believe that their sickness is a punishment for some past misdeed. “Imagine how stigmatising it is,” says Ms Mwingira.