(malignant edema, woolsorters disease)
Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Anthrax most commonly occurs in warm-blooded animals, but can also infect man. Anthrax spores can be produced in a dry form (for biological warfare ) which may be stored and ground into particles. When inhaled by humans, these particles cause respiratory failure and death within a week.
Anthrax is most common in agricultural regions where it occurs in animals. These include South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East. When anthrax affects humans, it is usually due to an occupational exposure to infected animals or their products. Workers who are exposed to dead animals and animal products (industrial anthrax) from other countries where anthrax is more common may become infected with B. anthracis. Anthrax in animals rarely occurs in the United States. Most reports of animal infection are received from Texas, Louisiana, Mississippi, Oklahoma and South Dakota.
Anthrax infection can occur in three forms: cutaneous (skin), inhalation, and gastrointestinal. B. anthracis spores can live in the soil for many years and humans can become infected with anthrax by handling animal products from infected animals or by inhaling anthrax spores from contaminated animal products. Anthrax can also be spread by eating undercooked meat from infected animals. It is rare to find infected animals in the United States.
Symptoms of disease vary depending on how the disease was contracted, but symptoms usually occur within seven days.
Cutaneous: Most anthrax infections occur when the bacterium enters a cut or abrasion on the skin, such as when handling contaminated wool, hides, leather or hair products (especially goat hair) of infected animals. Skin infection begins as a raised itchy bump that resembles an insect bite but within 1-2 days develops into a vesicle and then a painless ulcer, usually 1-3 cm in diameter, with a characteristic black necrotic (dying) area in the center. Lymph glands in the adjacent area may swell. About 20% of untreated cases of cutaneous anthrax will result in death. Deaths are rare with appropriate antimicrobial therapy.
Inhalation: Initial symptoms may resemble a common cold. After several days, the symptoms may progress to severe breathing problems and shock. Inhalation anthrax usually results in death in 1-2 days after onset of the acute symptoms.
Intestinal: The intestinal disease form of anthrax may follow the consumption of contaminated meat and is characterized by an acute inflammation of the intestinal tract. Initial signs of nausea, loss of appetite, vomiting, fever are followed by abdominal pain, vomiting of blood, and severe diarrhea. Intestinal anthrax results in death in 25% to 60% of cases.
The incubation period is usually within seven days.
There are no reports of the disease spreading from human to human. Direct person-to-person spread of anthrax most likely does not occur.
A second attack with this disease is unlikely.
Doctors can prescribe effective antibiotics. Usually penicillin is preferred, but erythromycin, tetracycline, or chloramphenicol can also be used. To be effective, treatment should be initiated early.
The disease could be fatal in untreated cases.
Although anthrax can be found globally, it is more often a risk in countries with less standardized and effective public health programs. Areas currently listed as high risk are South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East.
Anthrax vaccine is available for people in high-risk occupations. To prevent anthrax, carefully handle dead animals suspected of having anthrax; provide good ventilation when processing hides, fur, hair or wool; and vaccinate animals.
In countries where anthrax is common and vaccination levels of animal herds is low, humans should avoid contact with livestock and animal products, and avoid eating meat that has not been properly slaughtered and cooked. For high risk occupations, such as those exposed to potentially contaminated animal hair, wool or hides, vaccination is recommended. An anthrax vaccine has been licensed for use in humans. The vaccine is reported to be 93% effective in protecting against cutaneous anthrax.
The anthrax vaccine is a cell-free filtrate vaccine, which means it uses dead bacteria as opposed to live bacteria. Anthrax vaccine is indicated for individuals who come in contact in the workplace with imported animal hides, furs, bonemeat, wool, animal hair (especially goat hair), and bristles; and for individuals engaged in diagnostic or investigational activities which may bring them into contact with anthrax spores.
BioPort Corporation is the sole manufacturer of the anthrax vaccine. BioPort, whose headquarters is located in Lansing, Michigan, is owned by multiple shareholders. The two main companies that make up BioPort are Intervac, headed by William Crowe and Faud El-Hibri, and Michigan Biologic Products Inc.
The vaccine is US Food and Drug Administration (FDA)-licensed and has been routinely given in the US since 1970.
The immunization consists of three subcutaneous injections given two weeks apart followed by three additional subcutaneous injections given at 6, 12, and 18 months. Annual booster injections of the vaccine are required to maintain immunity.
Like all vaccines, anthrax vaccine may cause soreness, redness, itching,
swelling, and lumps at the injection site. About 30% of men and 60% of
women report these local reactions, but they usually last only a short while.
Lumps can persist a few weeks, but eventually disappear. Injection-site
problems occur about twice as often among women. For both genders,
between 1% and 5% report reactions at the injection site of 1 to 5 inches in
diameter. Larger reactions at the injection site occur in about one in a
hundred vaccine recipients.
Beyond the injection site, from 5% up to 35% will notice muscle aches, joint
aches, headaches, rash, chills, fever, nausea, loss of appetite, malaise, or
related symptoms. Again, these symptoms usually go away after a few days.
Serious events, such as those requiring hospitalization, are rare. They happen
about once per 50,000 doses. Severe allergic reactions can occur after any
vaccination, less than once per 100,000 doses.
A moderate local reaction can occur if the vaccine is given to anyone with a past history of anthrax infection.
Acute symptoms have varied. Depending on the vaccine lot used.
The most common side effects reported are: mild discomfort (localized swelling and redness at the site of injection), joint aches, and in a few cases, nausea, loss of appetite, and headaches.
There have been no long term side effects from the vaccine.
Anthrax vaccine is indicated for individuals who come in contact in the workplace with imported animal hides, furs, bonemeat, wool, animal hair (especially goat hair), and bristles; and for individuals engaged in diagnostic or investigational activities which may bring them into contact with anthrax spores. The vaccine should only be administered to healthy men and women from 18 to 65 years of age since investigations to date have been conducted exclusively in that population. Because it is not known whether the anthrax vaccine can cause fetal harm, pregnant women should not be vaccinated.
People who should not get the anthrax vaccine are those with a true hypersensitivity reaction (serious allergic reaction) to a previous dose of the anthrax vaccine, people infected with HIV, people who have other kinds of immune suppression, pregnant women, and people under 18 and over 65 years of age. Other temporary reasons for deferring anthrax vaccination include an acute respiratory disease or active infection, and a temporary course of immune-suppressing drugs such as steroids (e.g., prednisone).
People with preexisting autoimmune illnesses such as rheumatoid arthritis, lupus, multiple sclerosis are probably more likely to suffer a serious adverse reaction, as are those with neurologic disease, such as those who had polio in childhood.
Small quantities are made available as needed to civilians who are exposed to anthrax hazards in their work environment such as veterinarians, lab workers and others. Anthrax vaccine is produced exclusively by the Michigan Biologic Products Institute under contract to the Defense Department. Virtually all vaccine produced is earmarked for military use in recognition of the documented threat to military personnel.
Anthrax is diagnosed by isolating B. anthracis from the blood, skin lesions, or respiratory secretions or by measuring specific antibodies in the blood of suspected cases.
Doctors can prescribe effective antibiotics. Usually, penicillin is preferred, but erythromycin, tetracycline, or chloramphenicol can also be used. To be effective, treatment should be initiated early. If left untreated, the disease can be fatal.
The Department of Defense recommends servicemen and women contact their chain of command with questions about the vaccine and its distribution.