National Food Processors Association
ANTHRAX
What It Is and Addressing Inquiries

 Facts on Anthrax
What is anthrax?

Anthrax is an acute infectious disease caused by the aerobic, Gram-positive, spore-forming bacterium Bacillus anthracis.  It is a disease of mammals, including humans.  Ruminants (cattle, sheep and goats) appear to be most susceptible.  In humans it is generally seen in workers who are exposed to animals and animal products.  B. anthracis (or anthrax) spores survive for years in the environment.  Anthrax spores can be produced in dry form, which makes them easy to use for biological warfare since they can be stored and ground into a powder.
Questions Commonly Asked By Health Care Providers Anthraxqashealthprofessionals.pdf

Gram Stain of Bacillus anthracis
How does one get anthrax?
Anthrax is contracted by handling products from infected animals, inhaling anthrax spores from contaminated animal products or by eating undercooked meat from infected animals (Note: there have been no confirmed cases in the US from eating undercooked meat from infected animals).  Anthrax is not contagious (i.e. there is no human-to-human transmission). 

The anthrax spore and its several protective layers
Anthrax can be transmitted by three routes:
Inhalation
Cutaneous
Gastrointestinal

How is anthrax treated?
Antibiotic treatment is effective and may include:
Penicillin,
Doxycycline, and
Fluoroquinolones, such as Ciprofloxacin.
Naturally occurring anthrax strains are sensitive to penicillin, and this has historically been the preferred therapy for treatment; doxycycline is the preferred option from the tetracycline class of antibiotics.  However, because of reports that a vaccine strain of B. anthracis was engineered by Russian scientists to resist the penicillin and tetracycline classes of antibiotics, Ciprofloxacin has been the antibiotic of choice.

Treatment may also involve vaccination in combination with antibiotic therapy.
What are the symptoms and how does the disease progress?
The incubation period for anthrax is usually seven days or less, but may be up to 60 days.
 Cutaneous:

This is the most common form of anthrax, accounting for 95-98% of cases.  Bacteria enter through cut or abrasion of the skin.  The likelihood of cutaneous anthrax is low if skin exposed to anthrax spores is intact.  The illness usually begins as a raised itchy bump that resembles an insect bite but within 1-2 days develops into a fluid-filled vesicle and then a painless ulcer, usually 1-3 cm in diameter, with a characteristic black necrotic (dying) area in the center.  Lymph glands near the area may also swell, followed by other systemic symptoms.  Without antibiotic therapy as high as 20% of cases will result in death.  Death is rare with appropriate antimicrobial therapy.

Note the insect vector not common in Northern Hemisphere

Black eschar on ring finger

Note the black area in the middle

Early stages with minimal swelling and black areas
 

 Inhalation:

This is the most serious form of anthrax.  Most cases are the result of inhalation of spores from wool, hair, or hides of infected animals.  Initial symptoms resemble the common cold or flu (fever, cough, headache, vomiting, chills, weakness).  After several days the disease may progress to severe breathing problems and shock.  Death generally occurs in 1-2 days after onset of the acute symptoms, but may occur within hours.  Historically mortality in occupationally acquired illnesses has been around 89%; with modern treatment methods the rate should be lower, provided that diagnosis occurs in time.  Antibiotics are most effective if given before symptoms appear.  An extended duration of antibiotic therapy is recommended because of the persistence of spores resistant to the action of antimicrobial agents. 

LD 50 is 10,000 spores

 Gastrointestinal:

Gastrointestinal anthrax, which may manifest itself in one of two forms, is uncommon but may follow the consumption of contaminated meat (eaten raw or undercooked). There is an oral-pharyngeal form of the disease in which an ulcer forms in the mouth or esophagus and leads to swelling and sepsis.  The more common intestinal form is characterized by an acute inflammation of intestinal tract.  Onset time is 1-7 days.  Signs include nausea, loss of appetite, vomiting, fever followed by abdominal pain, vomiting of blood, severe diarrhea.  Intestinal anthrax results in death in 25-60% of cases.  No confirmed cases have been reported in the US, although there were presumptive cases in Minnesota in August 2000 after a farmer and his family consumed meat from an infected cow.

How much anthrax is necessary to cause illness?

The infective dose for humans is not well defined; however, CDC indicates that it takes thousands of spores to cause illness (approximately 5,000-10,000).   Based on primate data, the LD₅₀ (lethal dose sufficient to kill 50% of persons exposed to it) has been estimated to be 2500 to 55,000 inhaled anthrax spores.  However, it is important to remember that, where known exposure has occurred, antibiotics are likely to be effective in preventing serious illness and death.

 Where is anthrax found?
Anthrax is most common in agricultural regions, where it occurs in animals.  Anthrax spores have been documented in soil samples throughout the world, including South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean and the Middle East.  In the US most reports of animal infection are received from Texas, Louisiana, Mississippi, Oklahoma and South Dakota.

How is B. anthracis detected?
Clinical specimens:

B. anthracis in the blood or other infected tissues is easily recognized by its characteristic appearance – large, square-ended (“boxcar”-shaped) rods in pairs (sometimes chains of three or four).  It is readily cultured and forms unique “curled hair” colonies that are very mucoid (a loop touched to the colony and withdrawn results in a beaten-egg-white appearance).  Additional biochemical tests are used to confirm the organism’s identity.  The detection of serum antibodies that develop several weeks after exposure can also be used to confirm infection with B. anthracis (paired serum samples – early and late after exposure – are used to detect sero-conversion).  Rapid (6-hour) PCR tests exist in national reference laboratories such as the CDC.  Positives are confirmed culturally.

 Environmental samples:

Rapid field tests consist of antibody-coated test strips that give a color reaction when B. anthracis combines with the antibody.  These have been used to test suspicious materials such as powders in letters.  They are subject to false positives and false negatives and require follow up testing.

 Because of the hazards associated with anthrax, it is best to rely on appropriately trained personnel in public health or other specialized laboratories to conduct the testing. 

How heat resistant is B. anthracis?

The heat resistance of B. anthracis is similar to that of many strains of Bacillus.

Vegetative cells:           

Moist heat resistance: 

survived 5 but not 5.5 min at 65°C (149°F)

survived 3.5 but not 4 min at 70°C (158°F)

survived 2.5 but not 3 min at 75°C (167°F)

survived 50 but not 60 sec at 80°C (176°F)

 Dry heat resistance:  destroyed by 2 h at 92-100°C (198-212°F)

 Spores:

Moist heat resistance in physiological saline (17 strains tested): 

            D value at 90°C (194°F) – 2.5-7.5 minutes

            D value at 95°C (203°F) – 1.7-4.2 minutes

            Dry heat resistance:

            Death times of spore suspension on glass:

                  60 min at 120°C (248°F)

                  9 min at 160°C (320°F)

                  2.5-4 min at 229°C (444°F)

                  1.5-2 min at 288°C (550°F)

      Death time of 10⁸ spores on aluminum foil (0.2 mm thick):

                  30 min at 140°C (284°F)

                  8 min at 160°C (320°F)

                  2 min at 180°C (356°F)
How does drying affect B. anthracis?

Spores can survive for an extended period of time (in some cases as long as 50 years) under dry conditions. 
 

Does chlorine kill the spores?
As with other sporeformers, B. anthracis spores can be expected to be somewhat resistant to chlorine and survive chlorination of water.  Exposure for extended times and at higher concentrations will be more effective.  Hypochlorite solutions have been used effectively to decontaminate environmental surfaces contaminated with bodily fluids; however, these fluids would be expected to contain mostly vegetative cells.   Studies have shown that exposure to 2.3-2.4 ppm chlorine, pH 7.2, at room temperature for 2 hours kills B. anthracis vegetative cells. 

 Are cleaning compounds and chemical disinfectants effective against B. anthracis? 
Most commercial cleaners and disinfectants, including alcohols, phenols, quaternary ammonium compounds, ionic and non-ionic detergents, acids and alkalis, are ineffective against anthrax spores.  Surfaces contaminated with anthrax spores are sterilized with 10% formaldehyde, 2% glutaraldehyde, 3% hydrogen peroxide or 0.3% peracetic acid.   Other newer disinfectants may be useful but have not been tested against anthrax. 

What treatments are recommended for inactivation?

·        Expose to dry heat at 140°C (284°F) for 3 hours.

·        Immerse in water and maintain at 95°C (203°F) for 25 minutes or at 100°C (212°F) for 15 minutes.          

·        Autoclave at 120°C (248°F) for 10 minutes.

·        Expose to 10% bleach for two hours.

 Guidelines for Responding to Threats and Consumer Inquiries
cdc how to handle antrax.pdf

PHLS Interim Guidelines for Action in the Event of a Deliberate Release of anthrax
anthrax_guidelines.pdf

 

Interim Guidelines for Dealing with Packages suspected of containing Anthrax
totalmailguidanceplusflow.pdf

What should I do if I receive a threat that my plant/product has been contaminated with anthrax?

·        DO NOT PANIC.  Most threats are hoaxes.  However, given recent events, appropriate precautions should be taken. 

·        The steps to take depend on the nature of the threat: 

·        If the threat is received via phone do not put the caller on hold.  Try to obtain as many details as possible about the affected product, including whether a specific product is involved; the name, size, flavor, etc. of the product; the code on the product; how and when the product was contaminated; where the product is located; and why the product was contaminated.  Be sure to record the date and time of the call and note characteristics such as sex, age, speech and accent as best you can.   

¨      Contact appropriate personnel within the company (as outlined in your company’s crisis manual) and law enforcement officials.  Work with law enforcement officials to establish the credibility of the threat. 

·        If the threat is received via mail, handle the letter as little as possible to preserve fingerprints.  If possible, handle the letter with cotton gloves and place the letter between clear plastic sheets.  Tag the letter with the date and time received and the name of the person opening the letter.  Contact appropriate personnel as noted above. 

·        If you receive a suspicious letter or package, see NFPA’s fact sheet on RECOGNIZING AND HANDLING SUSPICIOUS PACKAGES/LETTERS (at www.nfpa-food.org), which recommends calling your state health department and local FBI.  This is critical if you receive an unidentified material purported to contain anthrax. 

·        If the threat is sent via the media or other group (government agencies, hospitals, stores) try to obtain as many details as possible about the affected product as noted above. 

¨      Contact appropriate personnel within the company (as outlined in your company’s crisis manual) and law enforcement officials.  Work with law enforcement officials to establish the credibility of the threat. 

 What should I do if I receive a consumer complaint alleging a product has been contaminated with anthrax?

With all the publicity about anthrax and bioterrorism, consumer fears are likely to result in claims of contamination if product does not appear as expected, especially if the consumer sees any type of powdery substance (flour, corn starch, etc.).  Our guidance in dealing with consumers is as follows:

When a consumer calls:

¨      Let the consumer know immediately that you are taking their inquiry/report seriously.  As a precaution, request that the consumer isolates the sample in a plastic, sealable bag, and washes their hands with soap and water.  Remain on the line as they complete your directions.  Attempt to reassure the consumer with facts pertinent to their concern, based upon the product’s characteristics and processing as appropriate (e.g. the use of flour, starch, flavor packets in the manufacturing/packaging of the product) if you believe they are mistaking a normal component for anthrax.

¨      In the event they’re reporting on an alleged anthrax incident involving a food product obtain as much information from the consumer as you can including information on the product (name, size, flavor, code, etc.).  Ascertain from the consumer whether the package was intact or showed any signs of damage when purchased, and where and when the product was purchased. 

§         Inform the consumer that you are taking their concern seriously and that you will get back to them after consulting with authorities.  Let them know that you will be contacting appropriate health officials.  Get all pertinent contact information for the consumer (name, telephone, address, etc.)

¨      Contact the state health department where the consumer is located and discuss the situation with the state officials.  They will advise you on the next steps.  (Note: the state health department may refer you to another agency or your local law enforcement)

¨      Call the consumer back to inform them of the actions to be taken.  In the event the alleged incident is evaluated to be credible, it is imperative that a public health official picks up the sample.  This is the best way to reassure the consumer and to protect your employees if there is a hazard.

¨      Follow-up with the state health department.

 A list of contacts at state health departments can be found at

http://www.fda.gov/ora/fed_state/directorytable.htm

All the information above is courtesy of CDC, PHLS, Hayes Publication and How Stuff Works. The information is for public health education only and has no commercial intentions.      LMP

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Last modified  March 2008