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Infectious Diseases

Anthrax

Anthrax is an acute zoonotic infectious disease caused by the bacterium Bacillus anthracis. It most commonly occurs in wild and domestic animals. Humans are exposed through infected animals or tissues. Incubation period is usually 1-3 days. It is a notifiable disease.

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Referral and warning signs

When to refer

Refer suspected Inhalation or Gastrointestinal Anthrax immediately to Hospital (H/RR). Refer Cutaneous Anthrax if signs of systemic illness, extensive oedema, or lesions on head/neck.

Red flags

  • Respiratory distress.
  • Signs of shock.
  • Altered mental status.
  • Severe abdominal pain / Hematemesis.
  • Cutaneous lesion with extensive swelling or on head/neck.

Signs and symptoms

  • Cutaneous Anthrax (Most common - ~95%):
  • - Starts as raised itchy bump resembling insect bite.
  • - Develops into a vesicle (1-2 days).
  • - Forms a painless ulcer (1-3 cm) with characteristic central black necrotic eschar.
  • - Adjacent lymph node swelling.
  • Inhalation Anthrax:
  • - Initial cold-like symptoms.
  • - Progresses after several days to severe breathing problems and shock.
  • Gastrointestinal Anthrax:
  • - Acute intestinal inflammation.
  • - Initial nausea, loss of appetite, vomiting, fever.
  • - Progresses to abdominal pain, vomiting blood (hematemesis), severe diarrhoea.
  • Symptoms usually occur within 7 days of exposure.

Risk factors

  • Exposure to infected animals (cattle, sheep, goats, camels, antelopes, herbivores) or their tissues.
  • Handling contaminated animal products (hides, wool, meat).
  • Inhaling spores from contaminated animal products.
  • Eating undercooked meat from infected animals.
  • Living in endemic areas.

Diagnosis

Clinical assessment

Suspicion based on characteristic skin lesion (painless ulcer with black eschar) or severe respiratory/GI illness with relevant exposure history.

Investigations

  • Isolation of Bacillus anthracis from blood, skin lesion fluid/biopsy, or respiratory secretions via Gram stain (shows bacilli) and Culture.
  • Measurement of specific antibodies in blood (serology).

Diagnostic criteria

Clinical presentation consistent with one of the forms of anthrax + exposure history +/- laboratory confirmation.

Management

Non-pharmacological management

  • Supportive care.
  • Report case (notifiable disease).

Pharmacological treatment

  • Cutaneous Anthrax (Uncomplicated): (LOC: HC2)
  • - Treat for 7-10 days.
  • - First line: Ciprofloxacin 500 mg PO every 12 hours.
  • - Alternatives: Doxycycline 100 mg PO every 12 hours OR Amoxicillin 1 g PO every 8 hours.
  • Inhalation/Gastrointestinal/Systemic Anthrax: Requires hospitalization, IV antibiotics (e.g., Ciprofloxacin IV + another agent like Clindamycin or Meropenem), and potentially antitoxin therapy (Specialist/RR management).

Monitoring

Monitor clinical response. Monitor for complications in severe forms.

Complications

  • Sepsis, shock.
  • Meningitis.
  • Respiratory failure (inhalation form).
  • Death (Untreated cutaneous: ~20%; Inhalation: often fatal; GI: 25-60%).

Prevention

  • Public health measures: Proper disposal of animal carcasses (burying, no burning), avoid skinning dead animals, do not eat meat from dead animals, restrict animal movement from infected areas.
  • Mass vaccination of livestock in endemic areas.
  • Human vaccination for high-risk groups (lab workers, animal product handlers in high-incidence areas).
  • Health education.

Patient education

  • Nature of the disease and transmission.
  • Importance of completing antibiotic course.
  • Prevention measures (avoiding contact with sick/dead animals, proper meat handling).
  • Need to report illness in animals to veterinary authorities.

Uganda-specific notes

Occurs sporadically, linked to livestock. Cutaneous form most common. Awareness of proper carcass disposal is vital for prevention. Ciprofloxacin is first-line treatment.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 2, Section 2.1.1

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