| |
Information from
CDC
| Clinical
Features |
Human anthrax has three major
clinical forms: cutaneous, inhalation, and
gastrointestinal. Cutaneous anthrax is a result of
introduction of the spore through the skin; inhalation
anthrax, through the respiratory tract; and
gastrointestinal anthrax, by ingestion. |
| Etiologic
Agent |
Bacillus anthracis, the
etiologic agent of anthrax, is a large, gram-positive,
nonmotile, spore-forming bacterial rod. The three
virulence factors of B. anthracis are edema toxin,
lethal toxin and a capsular antigen. B. anthracis
is considered to be a likely agent for use in acts of
biological terrorism. |
| Incidence |
In the United States, incidence
is extremely low. Gastrointestinal anthrax is rare but may
occur as explosive outbreaks associated with ingestion of
infected animals. Worldwide, the incidence is unknown,
though B. anthracis is present in most of the
world. |
| Sequelae |
If untreated, anthrax in all
forms can lead to septicemia and death. Early treatment of
cutaneous anthrax is usually curative, and early treatment
of all forms is important for recovery. Patients with
gastrointestinal anthrax have reported case- fatality
rates ranging from 25% to 75%. Case-fatality rates for
inhalational anthrax are thought to approach 90 to 100%. |
| Transmission |
For humans, the source of
infection in naturally acquired disease is infected
livestock and wild animals or contaminated animal
products. Human-to-human transmission is extremely rare
and only reported with cutaneous anthrax. |
| Risk
Groups |
Cutaneous anthrax is the most
common manifestation of infection with B. anthracis.
Inhalation (pulmonary) anthrax occurs in persons working
in certain occupations where spores may be forced into the
air from contaminated animal products, such as animal hair
processing. Occupational risk groups include those coming
into contact with livestock or products from livestock,
e.g., veterinarians, animal handlers, abattoir workers,
and laboratorians. |
| Surveillance |
For both livestock and humans,
anthrax is a notifiable disease in the United States. |
| Trends |
Among humans, there has been no
increase in naturally acquired infection in the United
States. Recently, considerable attention has been focused
on the potential for B. anthracis to be used in
acts of biologic terrorism. |
| Challenges |
Because B. anthracis has
a high probability for use as an agent in biologic
terrorism, CDC is expanding epidemiologic and diagnostic
laboratory capacities and technologies. This capacity
building, includes local and state health department
training. In addition, there are gaps in our understanding
of the immunology of anthrax and protection against
anthrax via vaccination. Also, post-exposure prophylaxis
against anthrax requires further investigation. |
| Opportunities |
Identify, transfer to CDC
laboratories, test, and improve as needed, rapid
diagnostic technologies developed for rapid identification
of B. anthracis in Department of Defense (DoD)
laboratories. |
|
December 2000
|
|
|
|
