The outbreak was traced to infected vervet monkeys cut up in the LABS for polio research; they came from close to the present outbreak in Uganda.

An afternoon at the beachside Bijilo Forest Park - a mile up the coast - gave us the chance to wander among baobabs, spotting hornbills, red colobus and green vervet monkeys.

I became acquainted with other animals: troops of vervet and redtail monkeys; the beautiful red colobus monkey; the shy bushbuck; the fat ginger bush pig.