Wildlife vet Lucy Spelman was summoned recently to Rwanda's Volcanoes National Park to examine Kwitonda,  a silverback mountain gorilla with a bad respiratory infection, which could have killed him. But how did Kwitonda get sick? One suspect: a sneezing ecotourist.

Recent outbreaks of SARS, Ebola, and avian flu have all fanned anxiety about zoonotic diseases -- those that can move from animals to humans. But humans are not the only ones at risk. As other species come into increasing contact with people and their pets and livestock, the results can be devastating: in South Africa's Kruger National Park, 25 lions succumb each year to bovine tuberculosis, probably imported by European buffalo. Endangered Ethiopian wolves are dying of rabies, in part because of contact with unvaccinated dogs.

Globalization is the main culprit. International travel and commerce carry foreign microbes to new continents; the trade in bushmeat, pets, and traditional medicines brings exotic creatures into unfamiliar places. What's needed, says Mary Pearl of the Wildife Trust, is a system of "smart surveillance," in which vets, physicians, ecologists, virologists, and zoologists pool their scientific skills to head off future crises.

Photo from istockphoto.com