In episode 46 of MicrobeWorld Video, filmed at the American Association for the Advancement of Science Meeting in Washington, D.C., Dr. Stan Maloy talks with Tracey McNamara, professor of pathology at Western University of Health Sciences College of Veterinary Medicine, about her role as the head pathologist at the Bronx Zoo during the 1999 West Nile virus outbreak in New York City. As several local residents were hospitalized with encephalitis of unknown origin, many crows and exotic zoo birds were dying off. It was determined that the patients had St. Louis encephalitis (SLE) which is transmitted to humans by mosquitoes that got the virus from infected birds. However, birds with SLE do not get sick and a possible connection between the dying crows and human cases was dismissed by many experts.

McNamara suspected there was more to this story because of the large number of birds that were also contracting encephalitis and struggled to make her voice and preliminary research heard that suggested a new disease may be emerging in North America. It wasn't until she connected with researchers at the US Army Medical Research Institute in Infectious Diseases (USAMRIID) in Ft. Detrick, Maryland, who quickly confirmed that the virus that was killing the crows and her birds at the Bronx Zoo was West Nile virus, a disease endemic to Africa and parts of Europe that also infects people.

McNamara's experience has made her a champion of One Health – "a call to action for collaboration and cooperation among health science professions, academic institutions, governmental agencies, non-governmental organizations, and industries towards improved assessment, treatment, and prevention of cross-species disease transmission and mutually prevalent, but non-transmitted, human and animal diseases and medical conditions."