Disease crossover from humans to animals—or vice versa—has become a growing concern, as Rivka Galchen explains for The New Yorker. Being able to predict which diseases will become a significant threat to humans and wildlife is one part science, one part intuition; humans, conservationists, and the farming community all depend on these educated guesses to help prevent devastating outbreaks.
For a time she worked in Monterey County, a more rural area, as a public-health epidemiologist, before moving to Los Angeles County, as a veterinarian in the department of public health. Ehnert really got to know the city by doing surveillance for West Nile virus, in 2002. (She grew up mostly in Northern California, with horses, cats, rabbits, and lizards—and also with her parents.) Angelenos would call in with reports of dead birds (mostly corvids), and she would drive out to pick them up—sometimes in Malibu, sometimes in poor neighborhoods where people were surprised that she turned up at all. “I remember picking up thirty-eight dead birds in one day,” Ehnert said. “This was before we had Google Maps on our phones. I had a Thomas Guide, if you even know what that is.”
