Facts About Anthrax
for Consumers and Livestock Producers
Facts About Anthrax
for Consumers and Livestock Producers
| Recent cases of anthrax among humans
have raised public concern about the disease and its potential as a weapon
of biological warfare. In response to these concerns, University of
Missouri Extension scientists have compiled answers to some
common questions about this rare disease.
Q. What is
anthrax? Anthrax is an acute
infectious disease caused by the spore-forming bacterium, Bacillus
anthracis. In the United States,
anthrax is rare among livestock, and even rarer among humans. Until recent
cases in Florida, only one other human case (in a North Dakota farmer
handling sick livestock in 2000) has been identified in the United States
in at least 15 years. Anthrax most commonly
occurs in wild and domestic lower vertebrates (cattle, sheep, goats,
camels, antelopes and other herbivores), but it can also infect humans
exposed to infected animals or tissue from infected animals. All mammals appear to be susceptible to anthrax to
some degree, but ruminants — such as cattle, sheep and goats — are the
most susceptible and commonly affected, followed by horses and then swine.
In ruminants, the disease generally is characterized by sudden death.
Ruminants contract the disease primarily through ingestion of soil-borne
anthrax spores. Anthrax does not spread by contact among animals. Because anthrax is
considered to be a potential agent for use in biological warfare, the U.S.
Department of Defense has begun mandatory vaccination of all active duty
military personnel who might be involved in conflict. Q: How common is anthrax, and who can get it? 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 from other
countries where anthrax is more common may become infected with B.
anthracis (industrial anthrax). Anthrax in wild livestock has occurred
in the United States. Q: How is anthrax transmitted? Anthrax infection can
occur in three forms: cutaneous (skin), inhalation and gastrointestinal.
B. anthracis spores can live in soil for many years, and humans can
become infected with anthrax by handling products from infected animals or
by inhaling anthrax spores from contaminated animal products. Anthrax also
can be spread by eating undercooked meat from infected animals. It is rare
to find infected animals in the United States. The two
Florida cases appear to be from inhaling anthrax spores. Inhalation
anthrax is usually fatal. The North Dakota case was cutaneous anthrax,
which results from exposure to spores or vegetative cells when the
bacterium enters broken skin (e.g., cut, abrasion, insect
bite),
such as when handling contaminated wool, hides, leather or hair products
(especially goat hair) of infected animals. The U.S. Department of Agriculture reports that
cutaneous exposure accounts for 95 percent to 98 percent of anthrax cases.
According to the Centers for Disease Control, about 20 percent of
untreated cases of cutaneous anthrax will result in death. Deaths are rare
with appropriate antimicrobial therapy. According to
the USDA, no cases of anthrax have ever occurred in the United States due
to ingestion of contaminated food or drink. Anthrax should not pose a
health hazard to consumers of meat because animals are inspected for
disease by federal and state meat inspectors before, during and after
slaughter. Q: What are the symptoms of anthrax? Symptoms of disease
vary depending on how the disease was contracted but usually occur within
7 days. Cutaneous: 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 centimeters in diameter, with a characteristic black, necrotic (dying) area in the center. Lymph glands in the adjacent area may swell. Inhalation: Initial symptoms may resemble a common cold. After several days, the symptoms may progress to severe breathing problems and shock. 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 and fever are followed by
abdominal pain, vomiting of blood and severe diarrhea. Intestinal anthrax
results in death in 25 percent to 60 percent of cases.
Q: Can anthrax be spread from person to person? Direct
person-to-person spread of anthrax is extremely unlikely to occur.
Communicability is not a concern in managing or visiting with patients
with inhalational anthrax. Q: How is anthrax diagnosed? Anthrax is diagnosed
by isolating B. anthracis from blood, skin lesions or respiratory
secretions, or by measuring specific antibodies in the blood of persons
with suspected cases. Q: Is there a treatment for anthrax? Doctors can prescribe effective antibiotics. To be effective, treatment should be initiated early. If left untreated, the disease can be fatal. More Information |
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Richard Randle, randler@missouri.edu |
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