With the recent occurrences of anthrax spores being sent through the U.S. mail system to select individuals, an increased interest in this biological contaminant has become evident. Fortunately, to date, a very limited number of contaminated letters have been found. Nevertheless, professionals trained to deal with microscopic fungal contamination may be contacted to provide assistance with identification or control. If you are requested to assist with potential anthrax contamination, check the Center for Disease Control and Prevention (CDC) and other reliable sources and information for the latest guidelines and information before acting.


Originally, humans contracted anthrax through direct contact with infected plant-eating animals such as cattle, sheep, goats, and horses, or animal products such as meat, wool, or hides. Anthrax bacteria are controlled through animal vaccination programs. Anthrax still occurs in countries where animals are not vaccinated, including some in Africa and Asia. Prior to September 11, 2001, anthrax was occasionally found in America. According to the CDC, there were 236 reported cases of anthrax in America from 1955 to December 1999. Most of these cases involved only skin contact. Prior to the bacteria laden letters, the last reported case of inhaled anthrax on American soil occurred in California in 1976 where a craftsman died from working with infected yarn. As a biological weapon, anthrax spores are carefully separated then mixed with a light powder so that when the mixture is released into the air it stays suspended so it can be inhaled. In this respect, anthrax makes a good weapon because is it very difficult to neutralize. Anthrax can survive in boiling water and has been found to live in contaminated soil for decades. Most other microorganisms quickly die when exposed to sunlight or high temperatures. The scientific description of anthrax is Bacillus anthracis. B. anthracis is a large, gram-positive bacterial rod that differs from many other types of bacteria because it forms a tough shell that allows it to remain dormant for long periods of time. As such, anthrax can remain a health threat for years even in harsh outdoor environments. Anthrax can affect people in three ways: skin contact, ingestion or inhalation. Human to human transmission of anthrax poisoning is extremely rare, but has been reported from individuals who have open sores on the skin caused by the bacteria. Skin sores from anthrax occur when spores of the bacteria invade the body by moving through abrasions or cuts in the skin. Until recently the majority of American anthrax cases were of this type. Early diagnosis and treatment of anthrax infection of the skin is usually successful. Case fatality rates for anthrax sores are considered to be 20% without antibiotic treatments and less than 1% with antibiotic treatments. Gastrointestinal anthrax enters the body through ingestion. This usually follows the consumption of raw or undercooked contaminated meat products. This type of poisoning is rare, but may happen as explosive outbreaks associated with the consumption of infected animal products. Case fatality rates for gastrointestinal anthrax are considered to be 25% to 60%. Inhalation anthrax occurs when the bacteria enters the body through breathing. It is currently estimated that an individual must inhale 8,000 to 40,000 spores of the bacteria to develop the infection in their lungs, although public health experts are reviewing the possibility that much smaller doses can harm immunocompromised people. This is by far the most lethal type of anthrax poisoning. Case fatality rates for inhalation anthrax are considered to approach 90% to 100%.


A person may be exposed to anthrax without contracting the disease. However, most individuals exposed to elevated levels of airborne bacteria will suffer from its health effects and exhibit symptoms of poisoning. Physical symptoms generally occur 1 to 6 days after exposure, although some individuals may exhibit symptoms as early as 24 hours or as late as 7 weeks after breathing bacteria laden dust. According to the CDC, people should watch for the following initial symptoms after potential exposure to anthrax: (1) fever (body temperature greater than 100 degrees Fahrenheit), (2) flu-like symptoms (cough, fatigue, muscle aches, nausea, vomiting, or diarrhea), and (3) sores on face, arms, or hands. Individuals showing these symptoms after possible exposure to anthrax should seek medical attention immediately. Health symptoms will vary depending on how the bacteria entered the body. Skin exposure to anthrax has a 1- to 12-day incubation period. An infection of the skin will begin as a small white pimple, progressing to a reddish purple swelling in 1 to 2 days, followed by an open sore that turns black. The lesion will usually remain painless, but patients can experience fever, malaise, headaches, and swelling of various lymph nodes. Ingested anthrax has a 1- to 7-day incubation period. Initial symptoms include nausea, loss of appetite, vomiting, and fever. As the poisoning progresses, an acute inflammation of the intestinal tract will normally occur. These symptoms are followed by abdominal pain, vomiting of blood, and severe diarrhea. Inhalation anthrax also has an incubation period of 1 to 7 days, but rarely may lay dormant in the lungs up to 60 days. Initial symptoms of anthrax poisoning of this type resemble common cold symptoms: sore throat, mild fever, headache, and general malaise. After several days, symptoms may progress to severe breathing problems and shock, with meningitis occurring frequently. Individuals exhibiting any of the symptoms previously mentioned after possible exposure to anthrax should seek medical attention immediately. Anthrax poisoning is diagnosed by isolating B. anthracis from the blood, skin lesions, or respiratory secretions or by measuring specific antibodies in the blood of persons with suspected cases.


There are two ways to neutralize anthrax inside the human body. Vaccines are available for susceptible individuals and antibiotics are available for persons who have been potentially exposed to the deadly bacteria. There exists a vaccine that offsets anthrax’s physical effects. The Food and Drug Administration (FDA) licensed the vaccine in 1970. The vaccine is only available to certain individuals. The Advisory Committee on Immunization Practices (ACIP) has recommended that the vaccination be given only to (1) persons who work directly with the organism in the laboratory, (2) military personnel deployed to areas with high risk for exposure to the organism, (3) persons who work with imported animal hides or furs in areas where standards are insufficient to prevent exposure to anthrax spores, and (4) persons who handle potentially infected animal products in high-incidence areas. The protocol for administering the vaccine is a series of shots given immediately, and after 2 weeks, 4 weeks, 6 months, 12 months, and 18 months. These shots are to be followed by annual booster shots. 30% of vaccine recipients experience redness, minor swelling, and tenderness at the site of injection. In the vaccine's 31-year history no long-term side effects have been reported. The course for preventing anthrax poisoning after exposure in the civilian population is the administration of antibiotics. There are two main antibiotics that can be administered, ciproflaxacin and doxycycline. Both of these are broad-spectrum antibiotic agents active against several bacteria, including anthrax. These antibiotics may cause side effects in certain individuals, including vomiting, diarrhea, headaches, dizziness, sun sensitivity, and rash.


Objects or surfaces suspected of being contaminated with anthrax can be tested using wipe, swab, or microvacuum samples. The collected dust is washed onto a petri dish that contains the appropriate nutrient agar and incubated for 1 to 3 days. The resulting growth is analyzed for the presence of the anthrax bacteria. Air samples can also be collected for viable sample analysis. Home test kits are available that allow people to swab surfaces and then rub the swabs on a petri dish. If the rubbed areas change color in 24 to 48 hours, anthrax is indicated. Surfaces with anthrax contamination are treated in a fashion very similar to those undergoing mold remediation. HEPA vacuums are used to clean all dust since even “weapons grade” anthrax spores are one micron or bigger in size. Various sanitizers are then used to kill any remaining bacteria. Because of its tough outer shell, formaldehyde has been the chemical agent used to destroy anthrax in the past. Currently the EPA and other agencies are investigating the effectiveness of other sanitizing compounds such as chlorine dioxide. Because of its potential to cause skin sores, anthrax remediation workers must use non-permeable body coverings that protect all exposed skin in addition to HEPA filtered respirators (usually PAPR’s).

Identification and Handling of Suspicious Packages or Envelopes

While few people will actually be impacted by anthrax laced letters, it is prudent to be suspicious of “odd” mail. Suspect mail includes (1) packages with inappropriate or unusual labeling, excessive postage, poorly handwritten information, strange return address, incorrect titles, threatening language, a postmark from a city or state that does not match the return address, and markings such as “Confidential” or “Do Not X-Ray”, (2) packages with unusual appearance, including a powdery substance felt through or appearing in the package or envelope, oily stains, discoloration, odor, lopsided or uneven envelope, and excessive packaging material such as masking tape, and (3) packages that contain other suspicious signs such as excessive weight, a ticking sound, protruding wires or aluminum foil. If you receive a suspicious looking parcel, handle it with extreme caution. Do not shake or empty the contents of any suspicious package or envelope. Do not carry the parcel, show it to others or allow others to examine it. Put the parcel on a stable surface. Do not sniff, touch, taste, bump, or look closely at it or any contents that may have spilled. Alert others in the area about the suspect parcel. Leave the area, close any doors, and take actions to prevent others from entering the area. If possible, shut off the ventilation system. Wash your hands with soap and water to prevent spreading potentially infectious material to the face or skin. If at work, notify a supervisor, security officer, or local law enforcement official. If at home, contact the local law enforcement agency. If possible, create a list of persons who were in the room or area when the parcel was recognized and a list of persons who also may have handled the parcel. Give this list to both the local public health authorities and law enforcement officials. The CDC does not recommend microwave, UV light, or ironing for reliable decontamination of anthrax spores found in letters in the mail system.

About the Author

Kurt MacDonald formerly served as an Environmental Specialist at Wonder Makers Environmental, Inc. Michael A. Pinto, CSP, CMP, is chief executive officer of Wonder Makers Environmental, Inc. Mr. Pinto is the author of over 140 published articles and several books including, Fungal Contamination: A Comprehensive Guide for Remediation. He completed his course work in environmental engineering and holds numerous other certifications in the environmental and safety areas. Michael can be reached at 269-382-4154 or This article was published in the Feb/Mar 2002 issue of the EIA Newsletter.