Factors affecting the performance of P22 ELISA for the diagnosis of caprine tuberculosis in milk samples. (July 2022)

• Record Type: Journal Article
• Authors: Ortega, J.; Infantes-Lorenzo, J.A.; Roy, A.; de Juan, L.; Romero, B.; Moreno, I.; Domínguez, M.; Domínguez, L.; Bezos, J.
• Is Part Of: Research in veterinary science. Volume 145(2022)
• Page Start: 40
• Page End: 45
• Publication Date: 2022-07
• Subjects: Caprine tuberculosis -- Milk -- P22 ELISA -- Lactation -- Azidiol; Veterinary medicine -- Periodicals; Veterinary Medicine -- Periodicals; Médecine vétérinaire -- Périodiques; Médecine vétérinaire -- Recherche -- Périodiques; Diergeneeskunde; 636.089
• DOI: 10.1016/j.rvsc.2022.02.008
• Languages: English
• ISSNs: 0034-5288

Abstract

Abstract: Caprine tuberculosis (TB) is a zoonosis caused by members of the Mycobacterium tuberculosis complex (MTBC). Caprine TB eradication programmes are based mainly on intradermal tuberculin tests and slaughterhouse surveillance. However, the use of serological test has been extended as a potential diagnostic tool in goats through the use of serum, plasma, or even milk samples. Milk production and the antibodies (Ab) present in milk can vary depending on several circumstances. In the present study, different factors that may affect the performance of humoral TB diagnosis were analysed using goat milk samples: 1) lactation stage, 2) a recent previous skin test (booster effect) and 3) the effect of freeze-thaw cycles on milk samples preserved with azidiol. TB-infected animals ( n = 44) were selected to evaluate the evolution of the Ab levels during the 6-month lactation period, along with its potential effect on the P22 ELISA results. In general, no significant changes ( p = 0.079) were observed throughout the study as regards Ab levels in milk samples between consecutive analysis although the reactivity to P22 ELISA decreased when samplings were performed at the last two months of the lactation. Regarding the booster effect, the quantitative results showed a significant variation ( p < 0.001) for both milk and serum samples when serological tests were carried out 15 days after the skin test. Finally, there were no significant differences ( p = 0.99) in the P22 ELISA results when using milk samples preserved with azidiol that had undergone freeze-thaw cycles. Highlights: Use of milk samples collected at the end of the lactation period can led to a decrease in the reactivity to P22 ELISA. Use of milk samples collected 15–30 days after the skin test could be used to maximize detection of infected goats. Several freeze-thaw cycles of milk samples preserved with azidiol did not significantly affect antibody detection.