MM 209-210; ID 1003-1008
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NAMES OF DISEASE:           Anthrax                       )
                                                 Black bane                  ) Cutaneous anthrax
                                                 Malignant pustule         )

                                                Tanner's disease            )
                                                Wool-sorters disease     ) Pulmonary anthrax

                                                Intestinal anthrax


    Bacillus anthracis. This is a Gram+ sporeforming rod that grows aerobically. It is non-motile and encapsulated.

    The virulence of B. anthracis is directly related to the presence of a capsule (D-glutamic acid). Even avirulent strains produce an exotoxin. The toxin is comprised of three distinct, antigenically active components. All are thermolabile proteins or lipoproteins:

        Factor I (Edema factor) - necessary for the edema-producing activity of the toxin

        Factor II (Protective antigen) - induces protective antibodies

        Factor III (Lethal factor) - essential for lethal effect

    Edema factor plus protective antigen = edema

    Lethal factor plus protective antigen = death


    The primary lesion usually develops at the site of a minor scratch or abrasion in an exposed area of the face, neck or upper extremities after an incubation period of 1-7 days. It begins as a small, inflamed papule which later becomes vesicular. Eventually the vesicle breaks down and is replaced by a black eschar. A striking "gelatinous" non-pitting edema surrounds the eschar for a considerable distance. At no stage is the lesion particularly painful. In severe cases of cutaneous anthrax the regional lymph nodes become enlarged and tender and the blood stream is eventually invaded.


    Cutaneous anthrax should be considered whenever a painless, pruritic papule on an exposed part of the body progresses through a vesicular stage to become a black, depressed eschar, regardless of antimicrobial therapy. The recovery of B. anthracis from vesicular fluid or exudate from the ulcer confirms the diagnosis. A differential diagnosis should include:

    1.     Staphylococcal skin lesions - more pyogenic, spread more rapidly, usually multiple lesions.
            Painful, only small black eschar.

    2.     Tularemia - the most common type is ulceroglandular. The skin is ulcerated at the point of
            entry and the regional lymph nodes become enlarged. This can be differentially diagnosed
            by serological techniques or isolation of the organism. Etiological agent is gram negative
            (Francisella tularensis).

    3.     Plague. Symptoms are similar to tularemia. Etiological agent is gram negative. (Yersinia

    4.     Milker's nodules. These occur only on the hands and do not generally form an eschar.

    5.     Orf. Generally occurs on the fingers. The orf virus is a poxvirus which shows characteristic
            pathology (tube-like intracytoplasmic inclusion bodies).

TREATMENT:     Penicillin V (oral) - mild cases

                            Procaine penicillin (IV) - severe cases


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