Johne’s Disease - complement fixation test (CFT)

Johne’s Disease – complement fixation test (CFT)

Species: Ovine, cervine, bovine, llamoid, caprine

Specimen: Serum

Container: Red top or gel tube

Collection protocol: Venepuncture

Special handling/shipping requirements:  Standard

General information about the disease:

Johne’s disease is an enteric infection of grazing ruminants and llamoids caused by Mycobacterium paratuberculosis. This test has a reported specificity of >97% indicating that an animal with a positive result almost certainly has Johne’s infection. The sensitivity of the test depends on the stage of the disease. In preclinical cases, the sensitivity is <50%.  However, with clinically affected animals, the sensitivity improves to approximately 55%.

General information about when this test is indicated:

CFT is used for specific requirements of some countries and for ancillary testing. ELISA is the first test of choice. 

Comparison with other related tests:  ELISA and AGID are other serological tests. Faecal PCR increases sensitivity and may be used to quantify shedding in individual animals or to test pools of up to 5 samples. Faecal Ziehl-Neelsen stains are also possible to check for acid fast organisms, but lack sensitivity.