Anthrax

Emergency Response

  • Approach from Upwind, Uphill, or Upstream
  • Isolate Immediate Area for at Least 300 Feet in all Directions
  • Keep Unauthorized Persons Away (Crowd Control)
  • Stay Upwind
  • Make Notifications
  • Decon with 5% bleach solution (for surface contamination if present) or soap and water (for personal contamination)
  • Obtain immediate medical attention

Management of Exposure Events

Potential Types of Exposures

The most likely methods of exposure to weaponized anthrax spores include:

  • Localized exposure to a white powder (such as a contaminated letter or package sent through the mail)
  • Contamination of a closed air supply (such as the ventilation system of a building)
  • Broad contamination of outdoor air (such as release of anthrax spores via a crop duster or similar aircraft)
  • Contamination of a commercial food or beverage source (which would cause gastrointestinal disease)

Only exposure to a white powder would be recognized at the time of the event. The other methods of exposure most likely would not be recognized until cases of disease occurred (unless indoor or outdoor air-monitoring systems are in place and capable of detecting B anthracis spores with some degree of sensitivity).

Handling of Suspicious Packages

According to the US Postal Service, suspicious letters or packages should not be opened (see References: US Postal Service). A letter or package should be considered suspicious if it:

  • Has any powdery substance on the outside
  • Is unexpected or from someone unfamiliar to you
  • Has excessive postage, a handwritten or poorly typed address, an incorrect title or a title with no name, or misspellings of common words
  • Has no return address or one that can't be verified as legitimate
  • Is of unusual weight, given its size, or is lopsided or oddly shaped
  • Has an unusual amount of tape
  • Is marked with restrictive endorsements, such as "Personal" or "Confidential"
  • Has a strange odor or stain

During the 2001 anthrax attacks, cases occurred among persons who opened mail and among persons who merely handled contaminated mail; therefore, suspicious packages or letters should be handled as little as possible. Forensic analysis has indicated that nearly 8 x 106 CFU were removed from the most highly cross-contaminated piece of mail found (see References: Beecher 2006). The CDC has published specific recommendations regarding handling suspicious packages or letters (see References: CDC 2001: Investigation of bioterrorism-related anthrax and interim guidelines for exposure management and antimicrobial therapy, October 2001):

  • Do not shake or empty the contents of a suspicious package or envelope.
  • Do not carry the package or envelope, show it to others, or allow others to examine it.
  • Put the package or envelope on a stable surface; do not sniff, touch, taste, or look closely at it or any contents that may have spilled.
  • Alert others in the area about the suspicious package or envelope. Leave the area, close doors, and take actions to prevent others from entering the area. If possible, shut off the ventilation system.
  • Wash hands with soap and water to prevent spreading potentially infectious material to face or skin. Seek additional instructions for exposed or potentially exposed persons.
  • If at work, notify a supervisor, a security officer, or a law enforcement official. If at home, contact the local law enforcement agency (ie, police).
  • If possible, create a list of persons who were in the room or area when the suspicious letter or package was recognized and a list of persons who also may have handled the package or letter. Give the list to both the local public health authorities and law enforcement officials.

If a patient reports exposure to a suspicious package that contains an unknown white powder, further evaluation should be undertaken by public health and law enforcement officials.

  • Recommendations for testing the package contents for B anthracis should be made on the basis of a risk assessment conducted by public health and law enforcement officials.
  • If the patient is considered at risk and is asymptomatic, then antimicrobial prophylaxis should be initiated pending results of microbiological testing of the package contents.
  • prophylaxis should be initiated pending results of microbiologic testing of the package contents.
  • If the patient has symptoms compatible with anthrax, then appropriate antimicrobial treatment should be administered.

A prospective longitudinal study of 124 subjects who may have been exposed to B anthracis during the anthrax attack in the US Capitol demonstrated that the significance of low-level exposure should not be underestimated (see References: Doolan 2007). The authors’ conclusion is based on the following:

  • Spore exposure primed immune responses in a dose-dependent manner and may have enhanced vaccine boost and recall responses.
  • Immune responses were detected among subjects inside the defined exposure zone as well as subjects outside the zone, implying more extensive spore migration than had been predicted.
  • Despite the fact that subjects received PEP with antibiotics, spore inhalation provoked immune system stimulation consistent with subclinical infection (and possibly antibiotic-aborted infection after germination of viable spores); greater levels of exposure corresponded to more complete immune responses.

Mass Exposure Events

  • In the event of a mass exposure, rapid delivery of prophylactic antibiotics to the exposed population would be critical to prevent illness and death (see References: Wein 2003). A recent simulation analysis suggested that postattack antibiotic therapy and vaccination of exposed individuals represents the most cost-effective strategy for a small-scale attack (see References: Schmitt 2007).
  • In emergency situations involving a bioterrorist release, state governments can request antibiotic and medical supplies from the Strategic National Stockpile through the CDC; the CDC is ready to rapidly deploy the stockpile as needed and can deliver initial supplies within several hours.
  • State and local health departments have bioterrorism preparedness plans in place to provide points of distribution (PODs) for mass antibiotic prophylaxis against anthrax and other biological agents as needed. During the 2001 anthrax outbreak, the New York City Department of Health and Mental Hygiene activated their incident command system and put their antibiotic distribution plan into effect. Lessons learned from this experience were published in June 2003 (see References: Blank 2003).
  • One analysis suggests that the critical determinant of mortality after an anthrax bioterrorism event is local dispensing capacity (see References: Bravata 2006). Modeling suggests a higher mortality among sites with low dispensing capacities, compared with those with high dispensing capacities. Doubling local inventories at high dispensing sites makes stockpiling five-fold more cost-effective than at low dispensing sites.
  • Mass prophylaxis campaigns carry the risk of overwhelming emergency health services owing to visits for actual or perceived medication-related adverse events (see References: Hupert 2007). Modeling suggets that the length of a mass prophylaxis campaign (eg, 10 days vs 2 days) plays an important role in determining the subsequent intensity in emergency services utilization due to real or suspected adverse events.

Surveillance During Exposure Events or for Early Detection of Outbreaks

Early disease outbreak recognition may significantly modify the outcome of a biological attack. A list has been developed of potential epidemiologic clues or "red flags" for an unusual event. Although these clues may be associated with natural outbreaks and bioterrorism events, their occurrence should heighten suspicion. Potential clues include the following (see References: Dembek 2007):

  • Highly unusual event with large numbers of casualties
  • Higher morbidity or mortality than is expected
  • Uncommon disease
  • Unusual disease manifestation
  • Lower attack rates in protected persons
  • Point-source outbreak
  • Multiple epidemics
  • Downwind plume pattern
  • Dead animals
  • Reverse or simultaneous spread of human and animal cases
  • Direct evidence

A review of the accidental release of aerosolized anthrax spores in Sverdlovsk showed that the resulting outbreak had many characteristics of an unusual event. Of the clues listed above, the first four were present in the outbreak, as were the sixth (point-source outbreak) and eighth and ninth (downwind plume pattern and dead animals). Despite concealment of information and confiscation of records by the Soviet military and government, public health response measures were implemented within 10 days of the event. The public health response is estimated to have prevented an additional 14% of fatalities.

Several reports have examined surveillance approaches for anthrax either in the setting of a known exposure or as an early population-based detection tool.

  • During 2003, the Connecticut Public Health Department (CPHD) implemented gram-positive rod surveillance for early anthrax detection (see References: Begier 2005). The CPHD reported that this laboratory-based surveillance system is a tool that could provide early detection of even a single case of inhalational anthrax.
  • During the 2001 anthrax outbreak, the New York City Department of Health and Mental Hygiene established the Cutaneous Anthrax Rapid Referral System for rapid referral and early diagnosis of anthrax cases (see References: Redd 2005). This system functioned to efficiently assess patients but also provided a mechanism for rapid centralized reporting, which could be a good surveillance model in the setting of a known mass exposure to anthrax.
  • Syndromic surveillance may be a valuable tool for early detection of anthrax cases in the setting of a mass exposure where relatively large numbers of cases would be expected to occur (see References: CDC 2005: Syndromic surveillance: reports from a national conference, 2004, Nordin 2005).
  • A recent review found evidence from the Sverdlovsk outbreak that livestock (such as cattle, sheep, and goats) can provide early warning of a bioterrorist event caused by B anthracis. In addition to livestock, cats and dogs might serve as markers for ongoing exposure risk following an anthrax bioterrorist attack (see References: Rabinowitz 2006).
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