BALTIMORE, MARYLAND—More than two years after the US anthrax letter attacks, the standard testing procedures for detecting the disease on indoor surfaces remain unreliable and unproven, according to two scientists who have studied the problem. The likely inaccuracy of those methods may leave the nation unable to determine the extent of contamination should another attack occur, they said at the annual American Society of Microbiology (ASM) Biodefense research meeting in Baltimore today (March 9).

Robert Hamilton, a professor of pathology and medicine at Johns Hopkins, and Barry Skolnick, an independent technical analyst, found that many of the technical details of the three basic methods used in the Senate office building and a Connecticut postal facility in 2001 and 2002 are ad hoc and not based on science. “That need not have been the case,” Skolnick said.

The three techniques call for swabbing, wiping, or vacuuming the surface, then transferring the sample to a culture dish to see whether it grows anthrax spores. Studying the microbiological evidence for testing back to 1917, the two researchers identified 16 different types of possible errors in these and other procedures. For instance, using synthetic swabs instead of cotton ones may underestimate how much anthrax is present. Moreover, some tests call for using dry swabs on dry surfaces, rather than wet ones that pick up many more spores. “This practice lacks any known scientific foundation,” Skolnick said.

Many methods also lack a control test that will “find” anthrax if the technician performs the test properly. Without it there is no assurance of accuracy, the scientists said.

One result of these problems, Skolnick said, is a US Government Accounting Office recommendation that the US Postal Service retest hundreds of its facilities because the original testing may have inaccurately concluded that no anthrax was present.

Skolnick said that “a few good days in the lab” spent testing known amounts of anthrax with different methods would provide considerable information about which ones yield accurate results. He and Hamilton said that every test should be peer-reviewed. As a model for testing, Skolnick cited a several decade-old NASA program to remove microbes from items it launches into space to avoid contamination.

The scientists found support for their ideas at the conference from Anthony Fauci, director of the National Institutes of Health's National Institute for Allergies and Infectious Diseases. When Skolnick raised the testing issue in a question-and-answer session on Sunday, Fauci said, “Thank you very much for your question. I quite frankly agree with the points you make.”

In particular Fauci agreed with Skolnick's contention that removing every last anthrax spore from an office may not be necessary, but the appropriate threshold for infectivity is not clear. “What happens if there are three versus seven spores?” asked Fauci, recalling that very issue being debated when the Senate office building was decontaminated after an anthrax letter was received there. He said he thought at the time that much more work needed to be done to answer that and other questions.

Elsewhere at the conference, researchers from the National Center for Infectious Diseases (NCID) at the Centers for Disease Control and Prevention (CDC) in Atlanta gave an update on the multiyear federal push to restore the US public health infrastructure. The goal, they said, is a system that can detect and react to outbreaks of deadly diseases—natural or bioterrorist-created—quickly and effectively. Funding has increased spectacularly, they said, from $40 million per year before 1999 to a total of $2 billion since then. As a result, “emergency response planning and plans are much more integrated” than they ever were before, according to Lisa Rotz, an NCID researcher.

In 1999, few public health labs in the country could detect anthrax, plague, tularemia, ricin, smallpox and others. Now a network of 80 public health labs, 11 military labs, 7 food-testing labs and others “are much more robust,” she said.

States are also making considerable progress in meeting a number of benchmarks the government set to assess their readiness to respond to a disease outbreak, Rotz announced. As of January, 45 states have a response plan for anthrax, and 39 have had their capabilities tested during a federally administered emergency drill. Forty-five have plague response plans, all have smallpox response plans, and more than three quarters have conducted response drills for the diseases.