Yesterday, Radio 4 broadcast a programme about the dangers from zoonoses - diseases which circulate among animals which can leap to infect humans. More frightening is the possibility that they are capable of mutating to allow human-to-human infection. Contact with both domesticated and wild animals which harbour pathogens has long imperilled the lives of people in Africa and South Asia. An increase in the attractiveness of these places as holiday destinations and availability of jet travel to them puts more of the world's population at risk
Now there is a warning that the United States could see epidemics of dengue fever, once thought eradicated there, for the same reason.