(ăn′thrăks)
[Pronunciation]
[Gr., coal, carbuncle]

An acute infectious disease caused by contact with, ingestion of, or inhalation of the spores of Bacillus anthracis, a large, spore-forming bacterial rod.
People who work with contaminated textiles or animal products usually contract it from skin contact with animal hair, hides, or waste (the most common form of the disease, accounting for 95% of cases), but the bacilli may cause a fatal pneumonia if they are inhaled.

Figure: ANTHRAX
Cutaneous anthrax: note the black, necrotic centers of the lesions




IMMUNIZATION
The anthrax bacillus has been prepared in aerosol form for use in biological warfare. As a result, some American troops have been vaccinated against the disease during their military training with one of several evolving vaccines. The effectiveness of the vaccine in disease prevention remains uncertain. Vaccination is also given to patients affected by active anthrax to prevent relapses.
See: biological warfare Standard Precautions Appendix

DIAGNOSIS
Diagnosis is made by isolating B. anthracis from blood, sputum, or skin lesion cultures.

SYMPTOMS
Signs and symptoms usually occur within 1 to 7 days after exposure, but can take up to 60 days. Early treatment helps to reduce fatalities. Cutaneous anthrax presents with small, pruritic lesions similar to insect bites that progress to large painless boils (“malignant pustules”), vesicles, or skin ulcers with necrotic centers and surrounding brawny edema, usually on an exposed body surface, such as the skin of the hand. Mortality is about 20% from untreated cutaneous anthrax and is less than 1% when treated with an antibiotic (penicillin, doxycycline, ciprofloxacin). GI anthrax involves acute inflammation of the intestinal tract from ingestion of anthrax spores. Symptoms include nausea and vomiting, decreased appetite and fever, progressing to abdominal pain, vomiting blood, and severe to bloody diarrhea. Antibiotic therapy limits mortality to from 25% to 60%. Inhalation anthrax (also called pulmonary anthrax or “Woolsorter's disease”) is marked by flulike symptoms progressing to fevers, sweats, cough, weakness, and rapidly developing respiratory failure, septic shock, and/or meningitis. Infection of the lungs may be suggested by the rapid onset of respiratory symptoms and chest x-ray or CT findings that may include widening of the mediastinum with hemorrhagic lymph nodes, hilar fullness, and pleural effusion. The disease is often fatal even with the appropriate antibiotic therapy.

TREATMENT
Persons exposed to anthrax (e.g., after its dissemination by bioterrorists) should receive a 60- to 100-day course of preventive therapy with ciprofloxacin, doxycycline, or penicillin G procaine. Individuals who have active infection with anthrax should receive two of the following antibiotics for a 60-day period: aminoglycosides, penicillin G (or amoxicillin), chloramphenicol, ciprofloxacin, doxycycline, imipenem or meropenem, rifampin, tetracycline, or vancomycin. Patients with pleural effusion benefit from drainage of the effusion with a chest tube.

PATIENT CARE
Health supervision is provided to at-risk employees, along with prompt medical care of all lesions. Terminal disinfection of textile mills contaminated with B. anthracis is supervised, using vaporized formaldehyde or other recommended treatment. All cases of anthrax (in livestock or people) are reported to local health authorities. Isolation procedures (mask, gown, gloves, hand hygiene, and incineration of contaminated materials) are maintained to protect against drainage secretions for the duration of illness in inhalation, GI, and cutaneous anthrax. For patients with inhalation anthrax, vital signs are monitored and respiratory support is provided. For patients with cutaneous anthrax, lesions are kept clean and covered with sterile dressings. Prescribed antibiotics are administered and the patient is assessed for desired and adverse effects. Frequent oral hygiene and skin care are provided. Oral fluid intake and frequent small, nutritious meals are encouraged.