Listeriosis


Listeriosis is a bacterial infection of the brain. It can affect a wide variety of animals including cattle, pigs, birds and humans. Listeriosis affects the nervous system of the animals and can lead to other problems such as encephalitis, still births and abortion. The disease spreads through the blood-stream and can lead to the failure of some organs in the body.

Common Names

Listeriosis is also known by the name of ‘circling disease’. This name is attributed to the animals walking in circular movements. Not all animals infected walk in circles, but the circular walking can be linked with loss of balance in cattle.

Causative Organism

Listeriosis is caused by the bacterium Listeria moncytogenes. This bacterium is extremely resistant and can live almost anywhere in soil, manure, and grass. Most infections are caused by ingestion of the bacteria, although inhalation or direct contact with the bacteria can also cause infection.

Common Symptoms

  1. Signs of restlessness
  2. Loss of appetite
  3. High body temperature
  4. Uncoordinated movements/Loss of balance
  5. Walking in circles
  6. Gradual paralysis
  7. Leaning against objects
  8. Nervous system disorders

How it Affects Cattle

Cattle affected with Listeriosis can die within 3 days of infection. In most cases, the cattle will live from 4 to 14 days. The nature of the disease makes Listeriosis very harmful. Many animals excrete the causative organism in their feces and milk. This is a common source of spreading the infection from animal to animal. If the organism is present in pastures, the animals with the weakest immune systems with usually be affected first. The younger animals typically have a weaker immune system, so they may show the first symptoms of an outbreak.

Regional Impacts

The bacteria which are responsible for Listeriosis can persist up to two years in manure and straw. The bacteria thrive in locations which are cold. Most of the reported cases of abortion in cows due to the disease appear during the winter months.

Risks & Dangers

Although cattle can be infected with Listeriosis, in most cases the risks are evenly divided between man and animal. People are also at risk for Listeriosis. All farm products from animal sources should be thoroughly cooked. Eating or drinking unpasteurized milk products from affected farms should be avoided.

Treatments

Listeriosis is treated with antibiotics. The dosage and type of antibiotic depends on the form of the disease. Treatment usually takes up to six weeks or more. The cure rate can vary depending on the severity of the infection and whether or not the bacterium has spread throughout the animal. The mortality rate in cattle is as high as 50%. Diseased cattle should always be separated from the healthy ones and treated by a veterinarian.

Vaccines & Prevention

There is no vaccine for Listeriosis. Preventing re-infection is solved by treating the whole herd at one time. This will reduce chances of the bacteria re-infecting.

References and Resources