Person: Álvarez Sánchez, Julio
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First Name
Julio
Last Name
Álvarez Sánchez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Veterinaria
Department
Sanidad Animal
Area
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19 results
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Item Evaluation of a new enzyme-linked immunosorbent assay for the diagnosis of tuberculosis in goat milk(Research in Veterinary Science, 2020) Roy, A.; Infantes-Lorenzo, J.A.; Dominguez, M.; Moreno, I.; Pérez Sancho, Marta; García Benzaquén, Nerea; García-Seco Romero, María Teresa; Álvarez Sánchez, Julio; Romero Martínez, Beatriz; Gortázar, C.; Juan Ferré, Lucía De; Domínguez Rodríguez, Lucas José; Bezos Garrido, JavierCaprine tuberculosis (TB) is a zoonosis with sanitary and economic repercussions. Caprine TB control programs are based on a test and cull strategy using the intradermal tuberculin tests and slaughterhouse surveillance. However, this approach is not always feasible and may have a limited sensitivity under specific circumstances. In this study, performance of a new experimental test based on the P22 protein complex (P22 ELISA) was evaluated in two TB-infected herds using milk and serum samples and compared with cell-based diagnostic tests. Samples from a low (n = 62, herd 1) and a high (n = 52, herd 2) TB prevalence herd were selected. Moreover, bulk tank milk samples from both herds were analysed using the P22 ELISA. At the end of the study, a group of animals (n = 21) was euthanized and subjected to post-mortem analysis and bacteriological culture. Significant differences (p < .001) on the qualitative and quantitative (ODs) results were observed between herds using both serum and milk samples in the P22 ELISA. The correlation observed in the quantitative results obtained in serum and milk samples was very strong in animals from flock 2 (rs = 0.91) and moderate in animals from flock 1 (rs = 0.46). Among the slaughtered animals, the P22 ELISA detected a higher proportion of lesion-culture positive animals than cell-based diagnostic tests (61.9 and 66.7% using milk and serum samples, respectively). The P22 ELISA using milk samples demonstrated a similar sensitivity compared with serum samples, suggesting it might be a valuable test for TB control in dairy goats.Item Effect of a recent intradermal test on the specificity of P22 ELISA for the diagnosis of caprine tuberculosis(Frontiers in Veterinary Science, 2024) Romero Martínez, Beatriz; Juan Ferré, Lucía De; Domínguez Rodríguez, Lucas José; Álvarez Sánchez, Julio; Bezos Garrido, Javier; Velasco, Carlos; Ortega, Javier; Domínguez, Mercedes; Ricón, Jaime; Moreno, InmaculadaCaprine tuberculosis (TB) is a zoonotic disease caused by members of the Mycobacterium tuberculosis complex. TB eradication programs in goats are based on the single and comparative intradermal tuberculin tests (SITT and CITT, respectively). Antibody-based diagnostic techniques have emerged as potential diagnostic tools for TB. P22 ELISA has been previously evaluated using samples collected after the intradermal tuberculin tests to maximize the sensitivity, a phenomenon known as booster effect. However, there is no information available on whether the use of this diagnostic strategy could lead to a decrease of its specificity (Sp). The aim of the present study was to elucidate the interference effect of a recent CITT on the Sp of the P22 ELISA in serum and milk samples collected at different times after the CITT from a TB-free herd (n = 113). The number of reactors to P22 ELISA was significantly higher (p < 0.01) on serum samples collected 15 days post-CITT compared to day 0, showing a decrease in Sp from 99.1% (95% CI; 95.2–99.8%) to 88.5% (95% CI; 81.3–93.2%). The number of reactors and the quantitative values of P22 ELISA were significantly higher (p < 0.01) in serum samples compared to milk. No significant (p > 0.05) changes in the Sp of the P22 ELISA were observed throughout the different time samplings using milk No significant (p > 0.05) changes were observed on days 30 and 60 post-CITT. In conclusion, the booster effect strategy may significantly decrease the Sp of P22 ELISA in TB-free herds when serum samples are used but not when milk is tested.Item Once bitten twice shy: Risk factors associated with bovine tuberculosis recurrence in Castilla y León, Spain(Research in Veterinary Science, 2023) Grau, Anna; Nácar, Jesús; Sáez-Lorente, José Luis; Mínguez, Olga; Pozo Piñol, Pilar; Bezos Garrido, Javier; Romero Martínez, Beatriz; Álvarez Sánchez, JulioPersistence of bovine tuberculosis (bTB) in cattle herd remains a major challenge in disease elimination due to the ineffectual removal of all infected animals in a bTB breakdown. Characterization of herds with a higher probability of experiencing further bTB breakdowns can help to implement specific risk-based policies for disease control and eradication. Here, our aim was to identify herd- and breakdown-level risk factors in bTB infected herds in Castilla y Leon, Spain, associated with a decreased time to recurrence and an increased risk of recurrence using a mixed effects Cox proportional hazards model and a multivariable logistic regression model, respectively. Results revealed that location (province), herd size and number of incoming animals/contacts were good predictors of a decreased time to bTB recurrence and an increased risk of becoming a recurrent herd. Additionally, the duration of the previous outbreak and the number of IFN-γ herd-tests applied in it were associated with increased odds of (an early) recurrence. Risk factors identified here can be used for early identification of herds in which bTB eradication may be more challenging and that should thus be subjected to increased control efforts. The characterization of high-risk herds may help to minimize the risk of reinfection and emphasize early detection and removal of bTB positive animals in the herd.Item Bovine tuberculosis in Spain, is it really the final countdown?(Irish Veterinary Journal, 2023) Bezos Garrido, Javier; Sáez Llorente, José Luis; Álvarez Sánchez, Julio; Romero Martínez, Beatriz; Díez Guerrier, Alberto Antoine; Domínguez Rodríguez, Lucas José; Juan Ferré, Lucía DeBovine tuberculosis (bTB) is a severe zoonotic disease that has major impacts on both health and the economy, and which has been subjected to specific eradication programmes in many countries for decades. This manuscript highlights the relevance of this disease in the context of the European Union (EU) and summarizes the epidemiological situation and the main tools (e.g. antemortem diagnostic tests, slaughterhouse surveillance, laboratories, comprehensive databases, etc.) used to control and eradicate bTB in the various EU countries with a focus on the situation in Spain. A comprehensive description of the specific bTB epidemiological situation in Spain is provided, together with an assessment of the evolution of different epidemiological indicators throughout the last decades. Moreover, the main features of the Spanish bTB eradication programme and its control tools are described, along with the studies carried out in Spain that have allowed the updating of and improvement to the programme over the years with the aim of eradication, which has been established for 2030.Item Eradication of bovine tuberculosis at a herd-level in Madrid, Spain: study of within-herd transmission dynamics over a 12 year period(BMC veterinary research, 2012) Alvarez, Julio; Perez, Andres M; Bezos Garrido, Javier; Casal, Carmen; Romero Martínez, Beatriz; Rodriguez Campos, Sabrina; Saez Llorente, Jose L; Diaz, Rosa; Carpintero, Jesus; Juan Ferré, Lucía De; Álvarez Sánchez, Julio; Domínguez Rodríguez, Lucas JoséBACKGROUND Eradication of bovine tuberculosis (bTB) through the application of test-and-cull programs is a declared goal of developed countries in which the disease is still endemic. Here, longitudinal data from more than 1,700 cattle herds tested during a 12 year-period in the eradication program in the region of Madrid, Spain, were analyzed to quantify the within-herd transmission coefficient (β) depending on the herd-type (beef/dairy/bullfighting). In addition, the probability to recover the officially bTB free (OTF) status in infected herds depending on the type of herd and the diagnostic strategy implemented was assessed using Cox proportional hazard models. RESULTS Overall, dairy herds showed higher β (median 4.7) than beef or bullfighting herds (2.3 and 2.2 respectively). Introduction of interferon-gamma (IFN-γ) as an ancillary test produced an apparent increase in the β coefficient regardless of production type, likely due to an increase in diagnostic sensitivity. Time to recover OTF status was also significantly lower in dairy herds, and length of bTB episodes was significantly reduced when the IFN-γ was implemented to manage the outbreak. CONCLUSIONS Our results suggest that bTB spreads more rapidly in dairy herds compared to other herd types, a likely cause being management and demographic-related factors. However, outbreaks in dairy herds can be controlled more rapidly than in typically extensive herd types. Finally, IFN-γ proved its usefulness to rapidly eradicate bTB at a herd-level.- Project number: 371
Item Infequus 2.0: Plataforma de enfermedades infecciosas en équidos(2022) Juan Ferré, Lucía De; Cruz López, Fátima; Álvarez Sánchez, Julio; Ancochea Nodal, Carlos; Bezos Garrido, Javier; Briones Dieste, Víctor; García Benzaquén, Nerea; González Domínguez, Sergio; Hernández Carrillo, Javier; Pérez Sancho, Marta; Rodríguez Bertos, Antonio Manuel; Romero Martínez, Beatriz; Santiago Llorente, Isabel; Domínguez Rodríguez, Lucas José Item Use of Whole-Genome Sequencing to Unravel the Genetic Diversity of a Prevalent Mycobacterium bovis Spoligotype in a Multi-Host Scenario in Spain(Frontiers in Microbiology, 2022) Pozo Piñol, Pilar; Lorente Leal, Víctor; Robbe-Austerman, Suelee; Hicks, Jessica; Stuber, Tod; Bezos Garrido, Javier; Juan Ferré, Lucía De; Sáez-Lorente, José Luis; Romero Martínez, Beatriz; Álvarez Sánchez, JulioDespite the efforts invested in the eradication of bovine tuberculosis in Spain, herd prevalence has remained constant in the country during the last 15 years (~1.5–1.9%) due to a combination of epidemiological factors impairing disease control, including between-species transmission. Here, our aim was to investigate the molecular diversity of Mycobacterium bovis isolates belonging to the highly prevalent SB0339 spoligotype in the cattle-wildlife interface in different regions of Spain using whole-genome sequencing (WGS). Genomic data of 136 M. bovis isolates recovered from different animal species (cattle, wild boar, fallow deer, and red deer) and locations between 2005 and 2018 were analyzed to investigate between- and within-species transmission, as well as within-herds. All sequenced isolates differed by 49–88 single nucleotide polymorphisms from their most recent common ancestor. Genetic heterogeneity was geographic rather than host species-specific, as isolates recovered from both cattle and wildlife from a given region were more closely related compared to isolates from the same species but geographically distant. In fact, a strong association between the geographic and the genetic distances separating pairs of M. bovis isolates was found, with a significantly stronger effect when cattle isolates were compared with wildlife or cattle-wildlife isolates in Spain. The same results were obtained in Madrid, the region with the largest number of sequenced isolates, but no differences depending on the host were observed. Within-herd genetic diversity was limited despite the considerable time elapsed between isolations. The detection of closely related strains in different hosts demonstrates the complex between-host transmission dynamics present in endemic areas in Spain. In conclusion, WGS results a valuable tool to track bTB infection at a high resolution and may contribute to achieve its eradication in Spain.Item Evaluation of the Effect of a Recent Comparative Intradermal Tuberculin Test on the Humoral Diagnosis of Paratuberculosis Using Serum and Milk Samples from Goats(Veterinary Science, 2024) Velasco, Carlos; Ortega, Javier; Gómez-Buendía, Alberto; Grau, Anna; López, Marisol; Álvarez Sánchez, Julio; Romero Martínez, Beatriz; Juan Ferré, Lucía De; Bezos Garrido, JavierParatuberculosis (PTB) and tuberculosis (TB) are two mycobacterial diseases with a severe economic and health impact on domestic ruminants. The ante mortem diagnosis of PTB is hampered, among other factors, by the limited sensitivity of all the available diagnostic techniques. Since TB-infected goats subjected to the comparative intradermal tuberculin test (CITT) may experience a booster effect on their antibody titer and a potential enhancement to the sensitivity of humoral techniques for tuberculosis, in the present study we aimed to evaluate this diagnostic strategy on the humoral diagnosis of PTB in serum and milk samples collected from a caprine herd that was TB free and PTB infected. The results from 120 goats indicated a significant increase (p < 0.001) in the quantitative response detected using an ELISA technique, conducted using serum and milk samples taken 15 and 30 days after performing a CITT (day 0 of the study); although, it did not translate into a significant increase in the number of reactors during any of the testing events (0, 3,15, 30 and 60 days post-CITT). Additionally, the number of ELISA-positive animals was higher for the serum versus the milk samples at both 15 and 30 days post-CITT. The increase in the quantitative ELISA result suggested a diagnostic strategy that maximizes ELISA sensitivity, mainly using serum samples, in PTB-infected herds; although, it may depend on individual differences and the interpretation criteria.Item Evaluation of Risk Factors Associated With Herds With an Increased Duration of Bovine Tuberculosis Breakdowns in Castilla y Leon, Spain (2010–2017)(Frontiers in Veterinary Science, 2020) Pozo Piñol, Pilar; Romero Martínez, Beatriz; Bezos Garrido, Javier; Grau, Anna; Nácar, Jesús; Sáez-Lorente, José Luis; Mínguez, Olga; Álvarez Sánchez, JulioThe persistence of bovine tuberculosis (bTB) in certain cattle herds is a major concern in countries pursuing disease eradication worldwide. The chronic nature of the disease, the lack of performance of diagnostic tools, and the presence of wildlife reservoirs may lead infected herds to require longer periods to achieve the officially tuberculosis-free (OTF) status. Here, we evaluated the impact of farm and breakdown characteristics on the probability of disease persistence in infected farms in Castilla y Leon, a bTB-endemic region of Spain, using survival and logistic regression models. Data from bTB breakdowns occurring in 3,550 bTB-positive herds detected in 2010–2017 were analyzed. A multivariable Cox proportional hazards model was fitted using time to recover OTF status as the response variable, and a multivariable logistic regression model using the chronic status (yes/no) for herds experiencing particularly long breakdowns as the outcome variable was also used. Both analyses revealed that county-level bTB herd prevalence, herd size, number of incoming animals in the previous 3 years, number of skin test reactors in the disclosing test, and number of days between the disclosing and follow-up tests were associated with increased breakdown duration. Production type was not consistently associated with chronic infection, suggesting that once infected, it is not a significant predictor of outbreak duration beyond the initial stages of the breakdown. Province-level location and number of animals that are bacteriology-positive also affected significantly the expected herd breakdown duration, but their effect became less significant over time. Risk factors identified in this study may help to identify herds more prone to suffer chronic bTB infection that may require additional control measures early on in a breakdown.Item Spatial dynamics of bovine tuberculosis in the Autonomous Community of Madrid, Spain (2010-2012)(PLoS ONE, 2014) Cruz Conty, Maria Luisa de la; Perez, Andres; Bezos Garrido, Javier; Pages, Enrique; Casal, Carmen; Carpintero, Jesus; Romero Martínez, Beatriz; Barker, Christopher M; Diaz, Rosa; Álvarez Sánchez, Julio; Domínguez Rodríguez, Lucas JoséProgress in control of bovine tuberculosis (bTB) is often not uniform, usually due to the effect of one or more sometimes unknown epidemiological factors impairing the success of eradication programs. Use of spatial analysis can help to identify clusters of persistence of disease, leading to the identification of these factors thus allowing the implementation of targeted control measures, and may provide some insights of disease transmission, particularly when combined with molecular typing techniques. Here, the spatial dynamics of bTB in a high prevalence region of Spain were assessed during a three year period (2010-2012) using data from the eradication campaigns to detect clusters of positive bTB herds and of those infected with certain Mycobacterium bovis strains (characterized using spoligotyping and VNTR typing). In addition, the within-herd transmission coefficient (β) was estimated in infected herds and its spatial distribution and association with other potential outbreak and herd variables was evaluated. Significant clustering of positive herds was identified in the three years of the study in the same location ("high risk area"). Three spoligotypes (SB0339, SB0121 and SB1142) accounted for >70% of the outbreaks detected in the three years. VNTR subtyping revealed the presence of few but highly prevalent strains within the high risk area, suggesting maintained transmission in the area. The spatial autocorrelation found in the distribution of the estimated within-herd transmission coefficients in herds located within distances <14 km and the results of the spatial regression analysis, support the hypothesis of shared local factors affecting disease transmission in farms located at a close proximity.