Bovine Anthrax Review

Anthrax is a reportable, zoonotic disease caused by the Gram-positive rod bacteria, Bacillus anthracis. Anthrax affects domestic and wild animals and secondarily, humans. This Article discusses the important features of Bovine Anthrax that are likely to come up on boards and the important aspects of identification and prevention of the disease.

Key Features:

  • Spores are resistant to heat, drying, and many disinfectants
  • Bloody discharge from orifices, absence of rigor mortis, rapid bloating, dark blood that does not clot
  • Do not open the carcass of an Anthrax suspect for necropsy
  • Zoonotic and reportable

Etiologic Agent

Bacillus anthracis characteristics:

  • Aerobic, Gram-positive, spore-forming rod
  • Spore is dehydrated with thick walls;can remain inactive for decades. Also called an endospore
  • Spores are resistant to heat, drying, and many disinfectants
  • Typically infects herbivores. Cattle, sheep, and goats most frequently
  • Spores germinate in animal host and grow rapidly in the vegetative form, causing a fatal septicemia

Clinical Signs and Diagnosis

Often, acute death is all that is seen in peracute forms but may be preceded by:
– Staggering
– Convulsions
– High fever
– Extensive swelling
– Cardiac or respiratory distress
– Depression/stupor

 Key findings (if you see these, you should definitely think of Anthrax)

  • Bloody discharge from the nose, mouth, or anus
  • Absence of rigor mortis
  • Rapid bloating
  • Dark blood that does not clot
Diagnosis can be confirmed by:

-If anthrax is suspected, do not perform a necropsy
-A blood or tissue sample should be submitted in accordance with the procedures of the diagnostic lab (contact them first).

Control and Prevention

1- Rapid detection, reporting and quarantine are key to prevention
2- Vaccination is effective (Given annually in endemic areas)
3- Post-exposure prophylaxis of asymptomatic animals helps control disease when seen in a herd
4- Suspect animals should be buried (or burned) without opening the carcass and without moving the animal, which may spread the bacteria.( Opening the carcass will cause the more fragile vegetative bacteria to form resistant spores)

Treatment

Early antibiotic treatment is essential. Ciprofloxacin, doxycycline, and penicillins are appropriate antibiotics. Extended treatment, usually 60 days is indicated to completely eradicate the organism.