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Assessment of the sensitivity of the bovine tuberculosis eradication program in a high prevalence region of Spain using scenario tree modeling

Investigation published in Preventive Veterinary Medicine

December 1st, 2019

In spite of the efforts invested to eradicate bovine tuberculosis (bTB) in cattle, the disease is still present in several developed countries, including Spain. Among the factors related with disease persistence in high prevalence areas, the lack of sensitivity of the screening test for detection of infected herds [single intradermal tuberculin (SIT) test] can play a major role. Here, a scenario tree model mimicking the diagnostic test scheme in place in the region of Castilla y Leon (Spain) was developed to estimate the probability of detecting bTB in an infected-non detected officially tuberculosis free (OTF) herd (herd sensitivity, HSe). In order to do so the probability of detecting at least one positive animal in the SIT test with/without post-mortem (detection of lesions and culture) confirmation in an infected herd was estimated using Monte Carlo simulation through @RISK (Palisade Co, NY, USA). Uncertainty on the accuracy of the diagnostic tests was introduced in the model using distributions based on the literature. The performance of the model was evaluated by comparing the predicted number of SIT/post-mortem positive animals in infected herds with those observed in newly detected bTB-infected herds in the region in 2011–2015. The estimated HSe of the SIT test was 76.2% (95% probability interval: 19.8–97.6). According to the model, bTB infection would be then confirmed through culture in 65.3% (95% PI: 50.0–82.3) of the herds detected through the SIT test, so that overall the proportion of infected-non detected OTF herds in which the infection could be confirmed after the initial SIT test was 49.6% (95% PI: 9.75–80.3). The predicted HSe of both SIT test and culture was directly correlated with herd size. Results from the model suggest a moderate but highly variable HSe of the current surveillance system in place for bTB detection in OTF herds located in high prevalence areas, that could be maximized by performing multiple tests within a year as indicated in the Spanish eradication program (with a median SIT HSe of 87% when two consecutive tests were considered). In addition, these results highlight the usefulness of performing subsequent SIT tests to rule out infection in SIT-positive herds even when the causative agent cannot be isolated




de la Cruz ML., Pozo P., Grau A., Nacar J., Bezos J., Perez A., Dominguez L., Saez JL., Minguez O., de Juan L. and Alvarez J..




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Assessment of the sensitivity of the bovine tuberculosis eradication program in a high prevalence region of Spain using scenario tree modeling

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Assessment of the sensitivity of the bovine tuberculosis eradication program in a high prevalence region of Spain using scenario tree modeling


Participants:

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

MAEVA SERVET, S.L.MAEVA SERVET, S.L..

Junta de Castilla y LeónConsejería de Agricultura y Ganadería. Junta de Castilla y León.

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

University of MinnesotaDepartment of Veterinary Population Medicine. College of Veterinary Medicine. University of Minnesota (UMM).

Ministerio de Agricultura, Pesca y AlimentaciónMinisterio de Agricultura, Pesca y Alimentación (MAPA).







Preventive Veterinary Medicine
FACTOR YEAR Q
2.302 2018

NLMID: 8217463

PMID: 31704560

ISSN: 0167-5877



TITLE: Assessment of the sensitivity of the bovine tuberculosis eradication program in a high prevalence region of Spain using scenario tree modeling


JOURNAL: Prev. Vet. Med.


NUMERACIÓN: 173:104800


AÑO: 2019


PUBLISHER: Elsevier Science Publishers


AUTHORS: de la Cruz ML., Pozo P., Grau A., Nacar J., Bezos J., Perez A., Dominguez L., Saez JL., Minguez O., de Juan L. and Alvarez J..


VISAVET PARTICIPANTS


5th
Javier Bezos Garrido
7th
Lucas Domínguez Rodríguez
10
Lucía de Juan Ferré
Last
Julio Álvarez Sánchez

DOI: https://doi.org/ 10.1016/j.prevetmed.2019.104800


CITE THIS PUBLICATION:

de la Cruz ML., Pozo P., Grau A., Nacar J., Bezos J., Perez A., Dominguez L., Saez JL., Minguez O., de Juan L. and Alvarez J. Assessment of the sensitivity of the bovine tuberculosis eradication program in a high prevalence region of Spain using scenario tree modeling. Preventive Veterinary Medicine. 173:104800. 2019. (A). ISSN: 0167-5877. DOI: 10.1016/j.prevetmed.2019.104800


UNITS:

Servicio de Epidemiología (EPI)