Caseous lymphadenitis (CL) is a chronic, contagious disease caused by the bacterium Corynebacterium pseudotuberculosis, which affects the lymphatic system, resulting in abscesses in the lymph nodes and internal organs. It is found mostly in goats and sheep and has no cure at the moment. CL is characterized by abscess formation in or near major peripheral lymph nodes (external form) or within internal organs and lymph nodes (internal form). Although both the external and internal forms of CL occur in sheep and goats, the external form is more common in goats, and the internal form is more common in sheep. CL is highly contagious and can be spread from animal to animal primarily through contact with material from abscesses (pus) or fomites (inanimate objects) contaminated with abscess material. When abscesses are present in the lungs, the organism may be transmitted through respiratory secretions (nasal discharge or coughing). In rare cases, C. pseudotuberculosis may be present in the milk.

Prevention and disinfection strategies are key to controlling the spread of this infection. The best defense against CL is to maintain a closed herd or subject all new animals or animals returning from off-property to a strict isolation protocol to prevent the infection from entering the herd. In herds where CL is already present, control and eradication can be difficult. A strict testing and culling protocol or separation of infected and uninfected goats can be helpful. Managing kids to prevent contact with CL positive dams and heat-treatment of colostrum or pasteurization of milk can help prevent spread. If you choose to control or eradicate CL, work with your veterinarian to develop an appropriate management program for your herd.

In conclusion, CL is a contagious disease that affects the lymphatic system, resulting in abscesses in the lymph nodes and internal organs. It is found mostly in goats and sheep and has no cure at the moment. Prevention and disinfection strategies are key to controlling the spread of this infection.