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| White Powder Incidents |
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Field Testing for White Powder Incidents: Why Not?
It’s 9:00am. A prominent businessman dials 911 complaining that he found a death threat and a tablespoon of white powder in his morning mail. Both he and his secretary got powder on their clothes. You are responding to his call.
Unfortunately, this scenario has become a common occurrence since the first anthrax threats in the fall of 2001. Although we have had some practice, proper handling of these events remains complex and occasionally counterintuitive. Given the situation above, What do you do?
Hand-held Assays?
Many of our fire departments and HazMat teams have purchased hand-held assays or field test devices to test samples--such as the businessman’s white powder--for biological agents such as anthrax. On the surface, use of these devices by first responders to rapidly identify biological agents makes perfect sense. Unfortunately, the technology used by these devices is far from perfect. Results from field tests often do not agree with thoseobtained from using established laboratory-based methods.
There are several reasons field tests do not produce accurate results: prior testing of chemicals can damage the devices so that they don’t “read” properly; the devices are not sensitive enough to detect small numbers of biological particles; the devices are finicky and may be inadvertently mishandled or results misinterpreted; but most important, when field tests are compared to reliably proven laboratory tests, the field tests are often just plain wrong.
Another problem that commonly arises from use of field tests is that the whole sample is used up for the field test, leaving nothing left for laboratory testing. When this happens, we can no longer get reliable test results and have no way to “diagnose” or diffuse the businessman’s threatening situation. And we lose irreplaceable criminal evidence.
These problems and numerous studies of field tests have led to a recommendation by the federal government to discontinue use of these devices altogether.
If we can’t test reliably in the field, what are we supposed to do?
“We can’t just sit there, right?” Right. But when faced with an unknown substance, there are proper and safe steps to follow:
First,
- treat the substance as if it were a chemical agent and clear the area.
- don’t keep people closed in with the substance*
- take names and locating information of potentially exposed people
- don’t decontaminate unless the powder burns, is irritating or other specific chemical indication
- those who have touched the substance should wash their hands
- those who have been exposed should go home, change clothes, shower and launder clothes normally
Next,
- using your agency’s protocols (or the Oregon State Police Threat Assessment),determine whether the item presents a credible threat,
- if the threat is credible,call the FBI and your local health department**
The FBI will direct the initial screening and packaging of the threatening letter and the unknown substance. The health department will make arrangements for appropriate and reliable laboratory--not field--testing of thesubstance; explain biological agents and testing to public safety personnel, frightened businessmen and others who may have been exposed; follow up exposed people after testing; and arrange for treatment if necessary.
What about preventing the spread of a biological agent?
In contrast to chemical exposures, where rapid action is necessary to preserve life and limb, biological agents don’t act so quickly. People who have been exposed to “bugs” are not contagious until the incubation period of the particular “bug” has run its course. This can take a couple of days or even a couple of weeks. During this time, an infected person cannot infect another person. Similarly--like that guy in your office who never catches cold--not every person who is exposed actually becomes infected. Biological agents do us the favor of giving us time to test for them and time to follow up and treat infected people. As a consequence, there is no benefit to rapid on-scene testing of potential biological specimens and there may be plenty of problems associated with their accuracy.
For questions, concerns or comments, please feel free to call:
Maria Gilson Sistrom, RN MSN
Oregon Health Services
Bioterrorism Project Manager
(503) 731-4024
*See next BioTip: Lockdown: NOT
**A credible threat with a biological agent may be a public health emergency. If you are unable to contact your
county health department, call the state health department at (503) 731-4024.
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| "Lockdown" NOT |
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A year ago this month a dramatic episode of the television show “ER” portrayed an unfortunate and inaccurate response to an outbreak of an agent of bioterrorism. Two sick children--having lounged in the crowded ER for hours--were found to have smallpox. In dramatic fashion, the ER was “locked down” by hospital security guards while the mutinous patients attempted to bash open the automatic doors in hopes of escape.
Reality check: this is TV and there is no smallpox disease anywhere in the universe. But the show portrayed a popular misconception: that closing sick people off from the rest of the world prevents the spread of disease. Unfortunately, it doesn’t.
Scenario: The mail clerk at a local business calls 911. After handling a package he discovers powder on the mailroom counter, all over his hands and down his shirtfront. The police arrive, discover the words “anthrax” written on the package and inadvertently get powder on their uniforms.
What should we do? Our first impulse is likely to be to close the mail clerk and the policemen off away from other people and certainly away from us. In other words, we want to quarantine them. But does quarantine really prevent the spread of disease? If it did, there would be no need for this BioTip, right?
Quarantining people exposed to a biologic agent doesn’t work for a number of reasons. For example, not everybody exposed will actually get infected—like a cold, you don’t get every one that comes around. Another reason is that every disease has an incubation period. Even if a person has been infected they won’t be contagious until they develop symptoms. The incubation period can be just 2 days for the common cold, it’s 12 days for smallpox, and it can be even longer for other diseases. The point is, it isn’t necessary to sequester people before they become contagious because they can’t spread disease yet. And finally, closing people up together with an infectious organism virtually assures that they WILL get infected—the longer a person spends with the organism the more likely it is they will get infected.
Our most important action, therefore, is not to close people up but to GET THEM OUT OF THERE! Rapid diagnosis and treatment of infected people can cure most of the agents of bioterrorism, so the most important thing to do is to figure out who was exposed and follow them in case they need treatment. (FYI, it is also important to remember that anthrax can’t be spread from person to person, so exposure to an infected person can’t infect you or anybody else).
So what should we do with the mail clerk and policemen covered in white powder, holding a package labeled “anthrax?” Since diagnosis, treatment and control of biological agents occurs after an event, not on-site, try
this:
- Assess for signs and symptoms of chemical irritation and treat accordingly;
- Remove everybody from the area and turn off the HVAC system;
- If the powder is voluminous, have the exposed people remove and bag their clothes
- otherwise have them wash their hands with soap and water on-site and shower when they get home;
- Take names and locating information of all potentially exposed people;
- Call the FBI and have them assist with threat assessment and transport of the specimen to the Public Health Lab (DO NOT use field assays on suspected biologic agents-see February 03 BioTip);
- Call the county health department and give them the names and locating information of the people who may have been exposed—they will follow up with education, counseling and diagnostic and treatment information as necessary.
If you have questions or want to discuss this novel approach, please call Maria Gilson Sistrom, RN MSN,Bioterrorism Project Manager, Oregon Health Services, (503) 731-4024.
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