Evaluation of single and comparative intradermal tuberculin tests for tuberculosis eradication in caprine flocks in Castilla y León (Spain).
Goats can act as reservoirs for tuberculosis (TB) infection. The main etiological agents of TB in goats are Mycobacterium caprae and Mycobacterium bovis and they infect also a wide range of domestic and wild animals and humans. Control programmes based mainly on the application of single and comparative intradermal tuberculin (SIT and SCIT respectively) tests are being implemented in certain regions of Spain with a high density of caprine flocks as Castilla y León, including goats with epidemiological relationship with cattle. The aim of this study was to evaluate the performance of the intradermal tests in naturally TB-infected caprine flocks from this region. The study was performed using data from 17,450 goats in 54 different flocks that were classified as TB-infected in the control programmes executed in 2010 and 2011. Data from 1237 goats from 7 dairy flocks depopulated after the first intradermal testing were used to estimate the sensitivity (Se) using bacteriology as the gold-standard. Overall Se of the SIT test using the severe interpretation was 43.9% (CI 95%, 40.4-47.4) and decreased to 38.8% (CI 95%, 35.5-42.3) using the standard interpretation. Overall Se of the SCIT test ranged between 21.3% (CI 95%, 17.6-25.4) and 7% (CI 95%, 4.9-9.8) depending of the interpretation criteria. A significant weak positive correlation was found between age and skin fold thickness (Spearman's test p<0.05). Results from this study yielded, in general, low Se values probably due the systematic detection and slaughter of reactors as a consequence of the eradication programme in previous years or the presence of factors that may interfere in the diagnosis. Therefore, these results suggest the necessity of including ancillary diagnostic tools and/or strict interpretation criteria to maximize detection of positive animals in infected settings.
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain.
Javier
J
Bezos
Servicio de Sanidad Animal de la Junta de Castilla y León, 47014 Valladolid, Spain.
Sergio
S
Marqués
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain.
Julio
J
Álvarez
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain.
Carmen
C
Casal
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain.
Beatriz
B
Romero
Servicio de Sanidad Animal de la Junta de Castilla y León, 47014 Valladolid, Spain.
Ana
A
Grau
Servicio de Sanidad Animal de la Junta de Castilla y León, 47014 Valladolid, Spain.
Olga
O
Mínguez
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain; Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Lucas
L
Domínguez
Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, 28040 Madrid, Spain; Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain. Electronic address: dejuan@visavet.ucm.es.
Lucía
L
de Juan
D000818:Animals; D005260:Female; D015511:Goat Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D006041:Goats; D008297:Male; D009161:Mycobacterium / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology; D018709:Statistics, Nonparametric; D014374:Tuberculin Test / Q000592:standards / Q000662:veterinary*; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*
Goat; Mycobacteria; SCIT test; SIT test; Tuberculosis