Caseous lymphadenitis (CLA) is an infectious disease caused by the bacterium Corynebacterium pseudotuberculosis, that affects the lymphatic system, resulting in abscesses in the lymph nodes and internal organs.

[citation needed] Caseous lymphadenitis causes considerable economic harm, because skins and carcasses have to be condemned.

The infection can spread through the blood or lymphatic system, causing abscesses to form in other lymph nodes or internal organs throughout the body.

[5] When abscess rupture, releases it huge numbers of bacteria onto the skin and wool and it results to the consequent contamination of the surrounding environment.

The disease is also easily spread through the materials that are used during the operation of the animals such as castration, identification with ear tags or by tattooing, and dehydration of abscesses.

Synergistic hemolysis inhibition testing, as done for equine species has the ability to generate false positive results when applied to small ruminants.

[7] Corynebacterium pseudotuberculosis has also been isolated from occurring in other species such as such as deer, cattle, pigs, hedgehogs, laboratory mice, camels, horses, and humans.