The bovine tuberculosis cluster in north County Sligo during 2014–16

Table 4 Information about animals tested using the interferon (IFN)-γ test, including number of tests, number of animals slaughtered and number (%) positive at post-mortem, by test type (diagnostic or quality control) and test result in the study area during 2014–16

Type of IFN-γ test, time difference between SICTT and IFN-γ	IFN-γ result	No. of tests (% positive)	No. slaughtered	No. (%) positive at post-mortem
Diagnostic IFN-γ test
All herds	Negative	352	106	2 (1.9)
All herds	Positive	114 (24.5)	92	9 (9.8)
All herds except Herd X^a	Negative	278	83	2 (2.4)
All herds except Herd X^a	Positive	55 (16.5)	55	9 (16.4)
Quality control IFN-γ test	Negative	9	9	2 (22.2)
Quality control IFN-γ test	Positive	174 (95.1)	169	112 (66.3)

Diagnostic IFN-γ tests were conducted on animals with a negative single intradermal comparative tuberculin test (SICTT) result based on an SICTT conducted no greater than 60 days prior to the IFN-γ test, whereas quality control IFN-ɣ tests were conducted on SICTT standard reactors. Herds within the study area were determined based on the District Electoral Division of the herd number
^aIn October 2014, herd X, with only 2 SICTT reactors, had IFN-γ testing applied, of which 59 animals tested IFN-γ positive. None of these animals had a positive SICTT subsequent to the IFN-γ test, and it is likely that these animals were all false-positive

ISSN: 2046-0481