I recently attended the “Biosecurity: Our Regional & National Response” research symposium in Kansas City, Mo., along with about 225 others, to listen to speakers talk about past zoonotic events (West Nile Virus), current/future threats and plans for surveillance and response — such as with the Biosecurity Research Institute and the National Bio and Agro-Defense Facility in Manhattan, Kan.
Tracey McNamara, DVM, Dipl. ACVP, Western University of Health Sciences College of Veterinary Medicine, gave quite a disturbing recount of the West Nile Virus (WNV) outbreak a decade ago that illustrated the lack of coordination between veterinary medicine (including zoo & wildlife), the government and public health. “The U.S. does not have an integrated strategy of biosurveillance,” she said.
It was McNamara’s persistence 10 years ago that played an integral role in the discovery and identification of WNV in the U.S. when she was on staff at the Bronx Zoo and crows were dying from an unknown reason, causing McNamara concern for the captive animals. This private entity then did its own investigation and found that crows died of myocarditis and they had hemorrhages over the cerebellum which caused lack of coordination and balance. Other captive bird species such as flamingos and an eagle also died. McNamara started looking for viral infections such as exotic Newcastle disease or highly pathogenic avian influenza, but they were ruled out. A 1999 a heat wave with heavy rains and flooding caused an explosion of mosquitos and a spike in avian malaria cases.
Encephalitis cases in New Yorkers and in birds made her wonder about a connection. The National Veterinary Services Laboratory in Ames demonstrated it was a flavivirus and negative for influenza, Newcastle, and Eastern/ Western/Venezuelan encephalitis. At the time, says McNamara, the Centers for Disease Control and Prevention said there was no relationship between birds and human deaths, and refused to accept the veterinary data.
“Birds and people were still dying,” said McNamara. She ended up going where they would take a potential biological agent seriously — the Armed Forces Institute of Pathology which took samples from her and discovered the agent was West Nile Virus which had never been seen in the Western Hemisphere.
The point of McNamara’s talk was that there were no strategic plans, alliances or even sharing among the various entities, including the wildlife/conservation agencies, departments of health, the CDC, zoos and others when a new biological threat emerged. She cited a woeful lack of wildlife veterinarians in this country.
“This illustrated a lack of sensitivity of public health to use aggregate data from other sources,” she said. Zoo animals had been a linch pin for diagnosis, but public health only wanted crow samples and wouldn’t test zoo animals. “I wondered if there were mammalian mosquitoes involved, not just avian mosquitoes. I questioned the wisdom of having the public pick up dead birds. It’s not transmitted just through mosquitoes but also aerosol transmission. We suspected fecal-oral and vertical transmission.” McNamara says those concerns were dismissed even though they published that information in 2000. “It took public health a while to catch on.”
The good news is now there are better communications systems in place between these various entities including the creation of a zoo WNV surveillance by the CDC, which has access to data from across the U.S. Zoos are built-in sentinel sites with captive species, vet staff and everything needed to deal with a WNV outbreak. “The point of biosurveillance is to find zoonotic threats in animal sentinels before people are in emergency rooms.”
All veterinarians are tasked with the preservation of public health, and this illustrates the importance of your training in domestic and foreign animal disease identification and surveillance.