Diagnosis of caseous lymphadenitis in sheep and goat

• Diagnosis of caseous lymphadenitis in sheep and goats may fail if a single test is used.
• Single testing policy for the diagnosis of caseous lymphadenitis is not advised and repetitive testing is essential.
• Each diagnostic method has limitations, consequently a specific test(s) validity differ from flock to another.

Caseous lymphadenitis (CLA) is a transmissible, insidious, serious disease of sheep and goat. It was firstly reported in the last decades of the 19th century. To date control of such disease is mostly unsuccessful because of its nature which leads to relapse of the problem even if a single case escapes diagnosis. Consequently, diagnosis of CLA is still a matter of intense research for more than a century. There is no single diagnostic test that could identify all cases or even different stages of the disease. This review discusses the most common diagnostic approaches for CLA in sheep and goat and to illustrate the opportunities and limitations of each approach and its validity to build up a diagnostic plan for CLA.