Quick -- Is It Anthrax?
New tests may answer that question in minutes instead of days
TUESDAY, Nov. 6, 2001 (HealthDayNews) -- Two new tests hold the promise of faster and more reliable identification of anthrax bacteria and infection.
The Mayo Clinic has announced a test, still very experimental, that can determine in less than an hour whether a sample from a human or environmental source has anthrax in it. Existing tests now take several hours to a few days to get the results. The new test compares known genetic sequences of anthrax to DNA in the sample.
And at Walter Reed Army Medical Center in Washington, D.C. , researchers will begin evaluating a test that is also intended to detect inhalation anthrax early. The test uses a radioactive antibody that binds to white blood cells that collect at sites of infection, allowing the infection to be detected with a gamma camera.
Early detection of inhaled anthrax can be critical because early treatment is needed to halt this rapidly progressing and deadly form of the disease.
The Mayo Clinic test was developed using the Swiss pharmaceutical company Roche Holding AG's LightCycler diagnostics instrument.
"This rapid identification will enable doctors to begin more timely treatment of patients who have been exposed to anthrax, and it will more quickly alleviate undue anxiety for people who haven't been exposed," said Dr. Franklin R. Cockerill III, the Mayo Clinic microbiologist who led the development team.
Cockerill says Mayo researchers have been using the same technology for more than a year to identify common infections like whooping cough, strep throat and herpes simplex (which causes cold sores).
Although noting that nothing is wholly reliable, Cockerill expressed confidence in this test method: "We've had no false positives in the laboratory."
Roche announced that it had stepped up production of the agents needed to perform the test and was making them available free of charge to 24 labs in the United States that are equipped with the LightCycler. It expects to expand that number in January.
Cockerill says that although the Food and Drug Administration haven't yet approved the test, the clinic is working with the Centers for Disease Control and Prevention and other federal agencies to make the test available. He expects speedy FDA approval. Roche must meet federal rules for labs to even use the tests experimentally, said FDA spokeswoman Sharon Snider, but the company is expected to do so.
Dr. Bradley Perkins, CDC's anthrax expert, responded to queries about the new test by saying, "To my knowledge, CDC, or particularly the scientists working on anthrax here at CDC, have not been in contact with the Mayo Clinic researchers in evaluation or interaction regarding this test."
Perkins did agree that there is room for development of new diagnostics for rapid diagnosis of anthrax. Currently, the CDC is using the PCR test that it developed with a number of academic partners. PCR (polymerase chain reaction) involves testing short stretches of genetic material to compare with the known genetic sequences in a sample. The method is considered highly reliable, and Perkins says the CDC is satisfied with it.
Cockerill says the advantage of the new test is its speed. "That's why we have helped Roche make the test available locally, to speed the preliminary diagnosis and improve patient care. We are pleased that after a few weeks of round-the-clock efforts, that goal has been achieved."
At Walter Reed, meanwhile, researchers plan to use a test developed by Palatin Technologies Inc. of Princeton, N.J., that uses an antibody the company calls LeuTech. Initially, up to 500 people who may have inhaled anthrax spores will be tested.
Dr. Perry Molinoff, executive vice-president of Research and Development at Palatin, says LeuTech can be used to detect an array of acute and chronic infections, including appendicitis, osteomyelitis (bone infection), post-surgical infections and bowel infections/inflammation. FDA approval is expected soon for these more common uses.
Although all of this sounds promising, Daniel Lim, a microbiology professor in the University of South Florida's Department of Biology and Department of Environmental and Occupational Health, offers one caution.
Lim, who has been working with the Roche LightCycler device for a year, says it works fine in a laboratory environment where the samples are clean, but he questions whether the results from either test will be as reliable in a real-world environment where "there can be lots of contaminants that interfere."
"It's just not as simple as the news reports make it sound," he says.
What To Do
The Center for Civilian Biodefense Studies offers information on anthrax for clinicians. But you don't have to be a medical expert to understand it.
The CDC also has an excellent anthrax site.