Before anthrax was a tool of terrorism, it was an animal disease that was rarely seen in this part of the United States but not entirely unknown to veterinary diagnostic laboratories, such as the one at Cornell.
Now the lab, which is headquartered in the College of Veterinary Medicine and formally known as the New York State Animal Health Diagnostic Laboratory, is a much-in-demand source of information and testing for the Bacillus anthracis organism that is causing so much concern.
"The phone's been ringing off the wall," said acting director of bacteriology Patrick McDonough, assistant professor of population and diagnostic medicine and bacteriologist in the lab that conducts more than 700,000 diagnostic tests of all kinds each year.
One of the most valuable services the diagnostic lab can offer is reliable, science-based information for veterinarians, public-health officials, farmers and the general public. In between phone calls, scientists at the diagnostic laboratory and other units of the veterinary college prepare detailed information for web sites, such as the lab's material on the "emerging issues" of anthrax and foot-and-mouth disease in animals: http://diaglab.vet.cornell.edu/issues.html#FMD. And as new aspects of the issue emerge, more information is added.
When a supposed expert said on CNN television that house cats could be carriers of anthrax, cat owners across the United States were alarmed and so were their veterinarians. So James R. Richards, director of the Cornell Feline Health Center, prepared a bulletin to veterinarians with instructions for handling suspected anthrax infection or contamination cases in cats. McDonough is preparing similar information about anthrax in dogs.
Although not certified to test for anthrax infections in humans, the veterinary lab has been designated by the USDA Animal and Plant Health Inspection Service (APHIS) as a regional center for animal anthrax testing for the Northeast, including New York state. So far, all the animal cases submitted to the Cornell lab have tested negative, including samples from bomb-sniffing and cadaver search dogs working in New York City-area investigations and the World Trade Center's "ground zero." Samples from Vermont cattle that died suddenly also tested negative for anthrax, as did samples from a Bronx Zoo giraffe.
The preliminary screening test for anthrax organisms takes less than 10 minutes. A sample taken from the ear of a ruminant is smeared on a microscope slide and stained to highlight significant parts of the bacterial capsules. Bacteriologists look for short chains of square-ended bacilli that resemble a train's boxcars, but a more conclusive result must await the culturing of the sample, which takes about 18 to 24 hours.
"Anthrax grows very quickly," McDonough notes. "Within 10 hours, we can see reasonably sized colonies." One test for cultured anthrax uses bacteriophages, which are viruses that infect only specific bacteria, The lab also uses fatty acid analysis, which looks for anthrax among a range of several bacteria thought to be bioterrorism agents. The use of PCR (polymerase chain reaction) tests will enable the Cornell lab to perform genetic identifications of anthrax and other agents. Suspected anthrax samples in nasal and throat swabs are handled in biosafety level 2 (BL-2) facilities at the lab.
Bioterrorists seeking anthrax would not find useful materials at Cornell, according to Robert O. Gilbert, associate dean of the veterinary college. "We do have a non-virulent strain of anthrax that was provided by CDC to enable us to perform required diagnostic testing, but this is a form that does not pose a threat to human or animal health." Virulent anthrax organisms had been in storage at the college several years ago when students in bacteriology teaching labs were taught to identify the organisms and differentiate them from similar bacteria, Gilbert noted. But that class no longer is offered and the anthrax organisms were destroyed, as was the archived anthrax from a cow in 1984 -- the last time the Cornell lab diagnosed a spontaneous case of anthrax. The cow had contracted anthrax from the site of an abandoned woolen mill in the Albany area.
Opportunistic anthrax organisms can lie dormant for years in the soil, waiting the ideal climatic conditions, such as heavy rains followed by a dry, windy period that distributes spores, bacteriologist McDonough observes. Fortunately, anthrax in cattle was never endemic in this state or the Northeast, although it continues to occur in the Southwest, including parts of Texas, as well as elsewhere in the world.
"We're trying to provide balanced information about the actual risks of anthrax," McDonough said. "Because anthrax is not endemic to this region, the sudden death of an animal is probably not a spontaneous case of anthrax." But the dissemination of anthrax through the mail and the possibility of agroterrorism, he acknowledges, casts an entirely new light on the issue.
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