To: Vermont Health Care Providers;
From: Susan Schoenfeld RN, MSPH, Deputy State Epidemiologist
Date: December 30, 2009
– Please Distribute Widely –
- The New Hampshire Department of Health and Human Services (NH DHHS) has identified a confirmed case of gastrointestinal anthrax in a New Hampshire resident.
- Public health officials believe the patient may have become infected at a drumming circle that took place on December 4 at the United Campus Ministry building, associated with the University of New Hampshire in Durham, New Hampshire. Samples from two African drums stored and used at the event have tested positive for anthrax, along with a third environmental sample from the same room. The NH DHHS is contacting individuals who participated in the December 4 drumming circle to discuss possible preventive therapy options. Anyone who brought their own drum to this event is being asked to call the NH DHHS at 603-271-4496 to discuss the possibility of having their drums tested.
- As of this time, no Vermont residents have been identified as participants in this event. However, providers are reminded to consider the diagnosis of anthrax in a clinically compatible human case with exposure as outlined above.
- Cases and suspect cases of human anthrax should be promptly reported to the Vermont Department of Health 802-863-7240. For these cases, laboratory testing is recommended and may be arranged by calling the Vermont Department of Health 24/7 at 802-863-7240.
Naturally occurring anthrax infection in humans can present as inhalational anthrax, cutaneous anthrax, or gastrointestinal anthrax.
a. Gastrointestinal anthrax (rare) is caused by ingestion of undercooked meat from infected ruminants (cattle, sheep, goat, deer). There is no evidence of transmission from milk. Inhalation of B.anthracis spores with subsequent ingestion is possible.
- Usual incubation period 1 to 7 days (up to 60 days is possible).
- Symptoms: Oropharyngeal: oral ulcers (can be necrotic), fever, sore throat, dysphagia, marked neck swelling and regional lymphadenopathy Intestinal: anorexia, nausea, vomiting, fever, severe abdominal pain, ascites, hematemesis, bloody diarrhea, cyanosis, sepsis, shock.
- Case-fatality rate is 25% to 60% with treatment. The impact of early antibiotic therapy is not known.
b. Cutaneous anthrax
- 95% of naturally occurring cases worldwide
- Introduction of B.anthracis spores into a break in the skin
- Incubation period is within 7 days
- Symptoms: Pruritic papule on arms, hands, face, or neck forms a vesicle that ruptures in 1 to 6 days to form painless, depressed ulcers. Characteristic black necrotic central eschar with local edema then forms (1-3 cm in size). After 1 to 2 weeks, the lesion dries and the black eschar separates from the skin leaving a scar. Fever, headache, lymphadenopathy, extensive edema, and other systemic signs may be present as well. Antibiotics decrease edema and systemic symptoms.
- Case-fatality rate < 1% with appropriate therapy
c. Inhalational Anthrax
- 5% of naturally occurring cases worldwide
- Caused by inhalation of B. anthracis spores
- Usual incubation period is less than a week (up to 60 days)
- Symptoms are biphasic: 1 to 3 days of low-grade fever, chills, headache, myalgias, drenching sweats, profound fatigue, minimally productive cough, nausea or vomiting, and chest discomfort. Rhinorrhea and productive cough are uncommon. These symptoms are followed by clinical improvement. Then, sudden onset of high fever, dyspnea, stridor, dry cough, tachypnea, and diaphoresis that progresses to septic shock and death in 1 to 2 days.
- Can be confused with symptoms of viral influenza.
- Chest radiograph may show mediastinal widening, paratracheal fullness, hilar fullness, and pleural effusions and/or infiltrates (this may be subtle on initial films). A chest CT showing hyperdense mediastinal and hilar adenopathy plus mediastinal edema suggests anthrax.
- Case-fatality rate for appropriately treated patients > 50%
- Testing for anthrax should only be done for those with clinically compatible syndromes.
- Testing is ideally performed PRIOR to receipt of antibiotics.
- Gram stain and culture can be performed on blood, pleural fluid, cerebrospinal fluid, tissue biopsy or discharge from cutaneous lesions.
- The receiving lab should be informed that anthrax is in the differential diagnosis.
- When a culture grows Bacillus spp. it may not be a contaminant.
- Preliminary identification of anthrax should be confirmed at the Vermont Public Health Laboratory.
- High index of clinical suspicion and rapid administration of effective antibiotics to suspect cases are essential for successful treatment.
- Ciprofloxacin 400 mg IV Q12 OR Doxycycline 100 mg IV q12 + 1-2 additional active antibiotics (such as rifampin, vancomycin, clindamycin) are recommended as first-line therapies.
- Patients with systemic illness should be assumed to have CNS spread and regimens should be chosen with good CNS penetration.
- Cephalosporins and trimethoprim-sulfamethoxazole should be avoided due to intrinsic resistance and constitutive and inducible B lactamase enzymes have been reported.
- Recommended preventive therapy for individuals exposed to Bacillus anthracis spores is usually 60 days of selected antibiotics in conjunction with a 3-dose regimen of anthrax vaccine.