There is mounting concern about the rate at which newly identified infectious agents are being detected as they cross the species barrier from animals to humans, causing human illness and death.1. Any of these agents, including new influenza viruses, have the potential to spread rapidly, such is the speed and extent of air travel.2

Seventy per cent of emerging infectious diseases are zoonoses.3 The discovery of a new Lassa fever-like virus—the highly lethal lujovirus4—and a new rhabdovirus with a reservoir in bats potentially adds to the burden of haemorrhagic fever outbreaks caused by Marburg and Ebola viruses. There have been 107 cases of infection with these last two viruses, and 55 deaths, in Uganda and the Democratic Republic of the Congo.5

There is also concern about the recent, sudden, and unheralded appearance of a new severe acute respiratory syndrome (SARS)-like virus—the “novel coronavirus”—in Saudi Arabia, Qatar, and Jordan. Nine laboratory confirmed human infections have been reported to the World Health Organization, five of which have resulted in death.6 The …