Listerellosis, Circling Disease
- Listeriosis is caused by the bacterium listeria monocytogenes and is commonly seen in cooler climates. The bacteria are very hardy and are found in soil, silage, manure, milk, urine, and drainage of the eyes and nose of infected animals. Listeriosis is spread when goats swallow, inhale, or get the bacteria in their eyes. The route by which it is spread can influence the symptoms. For example, swallowing the organism usually causes abortion, whereas infection through the eye or nose usually results in the nervous form.
- The abortion form usually shows no other symptoms. It can only be diagnosed by growing the organism from the aborted fetus in a laboratory. The nervous or encephalitic form has a rapid course and causes death in 4 to 48 hours after symptoms appear. Symptoms include circling in one direction, high fever, lack of appetite, red tissues around the eyes (maybe with blindness), and depression. Affected animals may have a paralysis of one side of the face, represented by a drooping ear, drooping eyelid, and saliva running from limp lips. Up to 20% of the goats in a herd may be involved. When near death, the animal will lie down and may have fits. Confirming diagnosis can only be made in a diagnostic laboratory.
- In developing countries it is most commonly seen when silage is put up too dry or not compacted tight enough to protect it from air.
- There are no effective treatments for small ruminants, and they usually die after infection. Large doses of penicillin may help in some cases. When an outbreak occurs, you should isolate infected animals. If silage is being fed, discontinue its use.
Health and Human Concerns:
Listeriosis can cause serious disease in humans. Be extremely careful when handling sick or dead animals. Do not eat any part of product of the sick or dead animal. Wash hands and disinfect clothes and shoes. Use all sanitary measures possible. If a herd is infected and milking animals have aborted, milk should be boiled or pasteurized before use. See the section on Mastitis for milk processing procedures. Pregnant women should avoid infected animals. Symptoms may range from a mild irritation on the hands and arms from assisting in the delivery of a kid to a severe blood poisoning disease. Encephalitis and abortion of pregnant women may also be produced by listeriosis.
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