Caseous Lymphadenitis (CLA) is a bacterial disease affecting sheep and goats, although it can also occur in livestock animals such as cattle. It is caused by the bacterium Corynebacterium pseudotuberculosis, which is highly contagious and can be transmitted through direct contact with animals or contaminated equipment and facilities.
The disease is characterized by the formation of abscesses in lymph nodes and visceral organs, leading to chronic and subclinical infections. CLA can cause significant economic losses for livestock farmers due to reduced milk and meat production and the costs associated with treatment and management.
Caseous Lymphadenitis Management in Goats
Causes of Caseous Lymphadenitis Disease
- CLA is caused by the bacterium Corynebacterium pseudotuberculosis.
- This small, non-motile, non-spore-forming, pleomorphic, Gram-positive bacteria can occur in curved, coccoid, club, and rod forms (coryneform morphology).
- There are two biotypes of C. pseudotuberculosis recognized: ovine/caprine biotypes and equine/bovine biotypes. The ovine/caprine biotypes lack nitrate-reducing capacity and mainly affect sheep and goats, causing superficial and visceral abscesses.
- The equine/bovine biotype usually reduces nitrate and mainly affects horses and cattle, causing ulcerative lymphangitis. The bacterium is highly contagious and can be transmitted through direct contact with infected animals or contaminated equipment and facilities.
Occurrence of Caseous Lymphadenitis Disease
- CLA has a worldwide distribution, and the disease has likely been disseminated worldwide by importing infected animals.
- CLA has been reported in various North and South American regions, including Australia, New Zealand, the Middle East, Asia, and Africa.
- There have been increasing reports of CLA in Britain and other European countries recently. The disease significantly impacts the livestock industry, causing economic losses due to the reduced milk and meat production and costs associated with treatment and management.
Disease Cycle of Caseous Lymphadenitis in Goat
- The disease cycle of Caseous Lymphadenitis (CLA) in goats involves the transmission of the bacteria Corynebacterium pseudotuberculosis through direct or indirect contact with infected animals or contaminated materials.
- The bacteria can survive in the environment for up to six months or more, increasing the risk of transmission through contact with contaminated objects or surfaces.
- Infected goats develop abscesses in their lymph nodes and visceral organs, which can rupture and release pus containing the bacteria.
- The bacteria can then contaminate the environment, increasing the risk of transmission to other animals. Traumatized buccal mucosa in goats can also increase the risk of infection through contaminated feed.
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Symptoms of Caseous Lymphadenitis Disease in Goat
- Symptoms of CLA in goats may include swelling and inflammation of peripheral lymph nodes, such as those in the head and neck regions, leading to the formation of abscesses.
- These abscesses may rupture and release the pus, leading to secondary infections and scarring.
- In more severe cases, the disease may progress to affect internal organs, leading to respiratory distress, weight loss, and decreased milk production.
- Affected animals may also display signs of lethargy, fever, and loss of appetite. Sometimes, the disease may be subclinical, with no visible symptoms.