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Risk factors associated with tuberculosis diagnostic failures in infected cattle herds

Oral communication in 13th International Symposium on Veterinary Epidemiology and Economics

August 23rd, 2012

Alvarez J., Perez AM., Marques S., Bezos J., Casal C., Grau A., Minguez O., de Juan L. and Dominguez L.

In spite of progresses achieved in the last decades in the field of bovine tuberculosis (TB) diagnosis, false negative cattle remains as a major issue for disease eradication in chronically infected herds. Implementation of ancillary diagnostic tests to the single intradermal tuberculin (SIT) test, such as the interferon-gamma
(IFN-γ) assay, has increased diagnostic sensitivity, but diagnostic failures may still persist. In the present study information from post-mortem analysis of culled cattle from more than one hundred TB-infected herds from all productive types (beef, dairy and bullfighting) present in Castilla y Leon (Spain) were used to detect individual risk factors associated to M. bovis positive culture results in animals testing negative in the SIT test (strict/standard interpretation), in the IFN-γ assay (with two thresholds) and in both tests assayed in parallel. Among the risk factors evaluated, age and productive type had a crucial impact on the reliability of the SIT test for accurate detection of infected animals regardless interpretation criteria, with older negative-animals and bullfighting cattle having a significantly higher risk of yielding a positive M.
bovis culture result. The same risk factors were detected in the analysis of the IFN-γ data, but association was weaker and in the case of the age restricted only to the oldest animals (>8 years). These results demonstrate that in spite of the high sensitivity of the diagnostic strategy in place false-negative results may occur. Thus, in chronically infected herds special attention should be paid to results of older animals. Implementation of IFN-γ assay in bullfighting herds contributed to minimize the risk of diagnostic failures




Participants:

Universidad ComplutenseServicio de Micobacterias (MYC). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).

Universidad ComplutenseDepartamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).


Link to 13th International Symposium on Veterinary Epidemiology and Economics





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13th International Symposium on Veterinary Epidemiology and Economics


August 20th-24th, 2012
Maastrich
The Netherlands

TITLE: Risk factors associated with tuberculosis diagnostic failures in infected cattle herds


TYPE: Oral communication


AUTHORS: Alvarez J., Perez AM., Marques S., Bezos J., Casal C., Grau A., Minguez O., de Juan L. and Dominguez L.


VISAVET PARTICIPANTS


First
Julio Álvarez Sánchez
4th
Javier Bezos Garrido
8th
Lucía de Juan Ferré
Last
Lucas Domínguez Rodríguez

DATE: August 23rd, 2012


CITE THIS COMMUNICATION:

Alvarez J., Perez AM., Marques S., Bezos J., Casal C., Grau A., Minguez O., de Juan L. and Dominguez L. Risk factors associated with tuberculosis diagnostic failures in infected cattle herds. 13th International Symposium on Veterinary Epidemiology and Economics, International Society for Veterinary Epidemiology and Economics, Maastrich, The Netherlands, August 23rd, 2012. (Oral communication)


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