Diagnostic accuracy of the Enferplex Bovine TB antibody test using individual milk samples from cattle.

Bovine tuberculosis is usually diagnosed using tuberculin skin tests or at post-mortem. Recently, we have developed a serological test for bovine tuberculosis in cattle which shows a high degree of accuracy using serum samples. Here, we have assessed the performance of the test using individual bovine milk samples. The diagnostic specificity estimate using the high sensitivity setting of the test was 99.7% (95% CI: 99.2-99.9). This estimate was not altered significantly by tuberculin boosting. The relative sensitivity estimates of the test using the high sensitivity setting in milk samples from comparative skin test positive animals was 90.8% (95% CI: 87.1-93.6) with boosting. In animals with lesions, the relative sensitivity was 96.0% (95% CI: 89.6-98.7). Analysis of paired serum and milk samples from skin test positive animals showed correlation coefficients ranging from 0.756-0.955 for individual antigens used in the test. Kappa analysis indicated almost perfect agreement between serum and milk results, while McNemar marginal homogeneity analysis showed no statistically significant differences between the two media. The positive and negative likelihood ratio were 347.8 (95% CI: 112.3-1077.5) and 0.092 (95% CI: 0.07-0.13) respectively for boosted samples from skin test positive animals. The results show that the test has high sensitivity and specificity in individual milk samples and thus milk samples could be used for the diagnosis of bovine tuberculosis.

Enferplex bovine TB antibody test and bovine TB diagnosis: letter to the editor.

Bovine tuberculosis is usually diagnosed using tuberculin skin and interferon gamma tests. However, it is clear these tests miss infected animals due to poor sensitivity. The Enferplex Bovine TB antibody test has been validated by the World Organisation for Animal Health as fit for purpose in diagnosing bovine TB. A recent paper by Madden and colleagues (Veterinary Research Communications published online 17 August 2023) presented data on the future risk of Enferplex test antibody positive animals developing bovine TB. We argue in this communication that this does not make sense. Also, the study design did not include measuring antibodies at the point of censure of the animals and hence the survival analysis performed was meaningless. Most significantly, the study misses the point that skin and interferon gamma tests fail to detect a significant proportion of infected animals identified by the Enferplex test.

Diagnostic accuracy of the Enferplex Bovine Tuberculosis antibody test in cattle sera.

Bovine tuberculosis is a contagious bacterial disease of worldwide economic, zoonotic and welfare importance caused mainly by Mycobacterium bovis infection. Current regulatory diagnostic methods lack sensitivity and require improvement. We have developed a multiplex serological test for bovine tuberculosis and here we provide an estimate of the diagnostic accuracy of the test in cattle. Positive and negative reference serum samples were obtained from animals from Europe and the United States of America. The diagnostic specificity estimate was 98.4% and 99.7% using high sensitivity and high specificity settings of the test respectively. Tuberculin boosting did not affect the overall specificity estimate. The diagnostic sensitivity in samples from Mycobacterium bovis culture positive animals following tuberculin boosting was 93.9%.The relative sensitivity following boosting in tuberculin test positive, lesion positive animals and interferon gamma test positive, lesion positive animals was 97.2% and 96.9% respectively. In tuberculin test negative, lesion positive animals and in interferon gamma test negative, lesion positive animals, the relative sensitivity following tuberculin boosting was 88.2% and 83.6% respectively. The results show that the test has high diagnostic sensitivity and specificity and can detect infected animals that are missed by tuberculin and interferon gamma testing.

Serological Analysis of Tuberculosis in Goats by Use of the Enferplex Caprine TB Multiplex Test.

Tuberculosis in goats is usually diagnosed clinically, at postmortem, or by a positive skin test. However, none of these approaches detects all infected animals. Serology offers an additional tool to identify infected animals missed by current tests. We describe the use of the Enferplex Caprine TB serology test to aid the management of a large dairy goat herd undergoing a tuberculosis breakdown. Initial skin and serology testing showed that IgG antibodies were present in both serum and milk from 100% of skin test-positive animals and in serum and milk from 77.8 and 95.4% of skin test-negative animals, respectively. A good correlation was observed between serum and milk antibody levels. The herd had been vaccinated against Mycobacterium avium subsp. paratuberculosis, but no direct serological cross-reactions were found. Subsequent skin testing revealed 13.7% positive animals, 64.9% of which were antibody positive, while 42.1% of skin test-negative animals were seropositive. Antibody responses remained high 1 month later (57.1% positive), and the herd was slaughtered. Postmortem analysis of 20 skin test-negative goats revealed visible lesions in 6 animals, all of which had antibodies to six Mycobacterium bovis antigens. The results provide indirect evidence that serology testing with serum or milk could be a useful tool in the diagnosis and management of tuberculosis in goats.