The U.S. government has set up a $60 million network to help detect a biological attack in 31 cities across the country, Homeland Security officials said on Friday.
The BioWatch system collects air samples at about a dozen sites in each of the cities. The samples are then checked for potentially deadly diseases that could be used in a biological attack.
The goal of BioWatch, located mostly in major urban areas such as Washington, New York City and Houston, is to discover if any bacteria or viruses have been released into the air as part of a biological attack. If so, the department would then mobilize public health and law enforcement officials.
Officials said the system will only identify germs once they are already in the air.
"By the time you get a hit (positive result), people could have already been infected," said Parney Albright, assistant secretary for science and technology at the Department of Homeland Security.
But detection will allow officials to identify the germ and dispense drugs to treat the disease, possibly before any symptoms appear among those infected.
"But this will not protect us from every possible attack," he added. He said BioWatch would not have been much use in trying to detect the deadly anthrax sent in letters mailed to politicians and the news media in 2001.
Since it was launched, BioWatch has analyzed more than half a million samples with one positive result -- in Houston last month when the air sensors detected fragments of tularemia.
Although tularemia is considered a potentially dangerous biological weapon in part because it is highly infectious, it occurs naturally -- as was the case in Houston -- and is commonly found in animals such as rabbits.
Labor intensive system
Air samples are collected at least once a day and taken to special laboratories where technicians extract DNA samples to do genetic testing for a number of diseases.
The tests are specific for each germ that is viewed by the government as a likely biowarfare or terrorism agent. Officials would not say what bugs they screen for, saying only that it was less than a dozen. Experts have said they could include the germs that cause anthrax, tularemia, smallpox, plague, botulism and hemorrhagic fever.
Officials said the system covers half the U.S. population, but some experts have questioned the amount of air that is tested. They say sensors need to correctly positioned to accurately detect an attack.
The program costs about $2 million per year per city, much of which is spent in labor costs, Albright said.
BioWatch is funded by Homeland Security, and has been operating since early 2003, when officials grew worried about the threat of biological attack in light of the war in Iraq.
The department set up BioWatch sensors at many of the Environmental Protection Agency's air quality monitoring stations. The laboratory analysis is done in conjunction with the Centers for Disease Control and Prevention.