Listeriosis

By Jack Mauldin
January 15, 2009
Listeriosis is caused by a bacteria that can affect all mammals including humans. In the goat industry is is called the "Circling Disease" because affected animals commonly walk compulsively in a circle. The bacteria are found in the  environment, especially in rotting vegetation such as  poorly prepared silage. The infection is normally cause by the goat ingesting the organism through environmental or fecal contamination of their feed. The disease is most common during the cool weather. Though the bacteria is easily killed by common disinfectants, it can survive in feces, silage, and tissue for 5 or more years.

The disease is most common in adult goats. The source of infection in herds can be when mammals and birds feces spread the bacteria in the soil or on feed areas..
Signs and Symptoms

Early signs are:

  • Depression
  • Decreased appetite
  • Decreased milk production
  • Fever

There are two forms seen:

  • Encephalitic form - In the brain. The bacteria enters through breaks in the oral mucosa and migrate to the brain. Signs are:
    • Incoordination
    • Circling in the same direction
    • Seizures
    • Hind lib paralysis
    • Facial nerve disorders
    • Excessive salivation
    • Slack jaw
    • Impaired swallowing
    • Cornea inflammation
  • Septicemic form - Blood-borne. The bacteria enters through the intestines. Signs are:
  • Diarrhea
  • Abortion

 
Treatment

Required detection early in the course of the disease. Large doses of antibiotics such as penicillin and tetracycline are generally given along with fluids, electrolytes

  • Administer penicillin and tetracycline orally at 25 mg/kg for 1 week or 11.5 mg/lb per day for 3 consecutive days. In the encephalic forms, intravenous sodium penicillin at a dosage of 40,000 IU/kg or 18,000 IU mg/lb every 6 hours until signs are improved, followed by administration of procaine penicillin at a dosage of 20,000 IU/kg body weight twice a day for 3 days.
  • Administer intravenously 1-2 mg/kg or 0.05 mg/lb mg/kg or dexamethasone is recommended to treat inflammation in the brain. Intravenous fluid and electrolyte therapy and supplemental feeding are also recommended.
  • Discard spoiled feed and hay.
  • Improve sanitation of pens, water supply, pasture, and housing.
  • Keep wild birds away from the herd as much as possible as these birds may serve as vectors for the disease.
  • Identify the source of infection in order to help eliminate the causative agent.
  • In the case of abortion, isolate aborting does and send aborted fetuses and placentas to a diagnosis center for isolation of the causative agent. (Wear latex gloves when handling placental membranes.)
  • If a doe has listeriosis, feed kids pasteurized colostrums, milk, or a milk substitute.
  • Human listeriosis is associated with the consumption of contaminated meat products, as well as milk and cheese obtained from nonpasteurized milk. Humans can also contract listeriosis by handling fetuses and specimens from aborted animals, and newborns of infected does. Always wear gloves when handling fetuses and specimens from aborted does.

This treatment comes from

Maria Lenira Leite-Browning, DVM, Extension Animal Scientist, Alabama A&M University