Person: Navarro Gómez, Alejandro
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First Name
Alejandro
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Navarro Gómez
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Universidad Complutense de Madrid
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Item Assessment of the sensitivity and specificity of serological (IFAT) and molecular (direct PCR) techniques for diagnosis of leishmaniasis in lagomorphs using a Bayesian approach(Veterinary Medicine and Science, 2016) Cruz Conty, María Luisa de la; Pérez, Andres; Domínguez, Mercedes; Moreno, Inmaculada; García Benzaquén, Nerea; Martínez Alares, Irene; Navarro Gómez, Alejandro; Álvarez, Julio; Domínguez Rodríguez, Lucas JoséLeishmaniasis, caused by Leishmania infantum, is a vector-borne zoonotic disease that is endemic to the Mediterranean basin. The potential of rabbits and hares to serve as competent reservoirs for the disease has recently been demonstrated, although assessment of the importance of their role on disease dynamics is hampered by the absence of quantitative knowledge on the accuracy of diagnostic techniques in these species. A Bayesian latent-class model was used here to estimate the sensitivity and specificity of the Immuno-fluorescence antibody test (IFAT) in serum and a Leishmania-nested PCR (Ln-PCR) in skin for samples collected from 217 rabbits and 70 hares from two different populations in the region of Madrid, Spain. A two-population model, assuming conditional independence between test results and incorporating prior information on the performance of the tests in other animal species obtained from the literature, was used. Two alternative cut-off values were assumed for the interpretation of the IFAT results: 1/50 for conservative and 1/25 for sensitive interpretation. Results suggest that sensitivity and specificity of the IFAT were around 70–80%, whereas the Ln-PCR was highly specific (96%) but had a limited sensitivity (28.9% applying the conservative interpretation and 21.3% with the sensitive one). Prevalence was higher in the rabbit population (50.5% and 72.6%, for the conservative and sensitive interpretation, respectively) than in hares (6.7% and 13.2%). Our results demonstrate that the IFAT may be a useful screening tool for diagnosis of leishmaniasis in rabbits and hares. These results will help to design and implement surveillance programmes in wild species, with the ultimate objective of early detecting and preventing incursions of the disease into domestic and human populations.Item Environment and Offspring Surveillance in Porcine Brucellosis(Frontiers in Veterinary Science, 2022) Rebollada Merino, Agustín Miguel; Pérez Sancho, Marta; Rodríguez Bertos, Antonio Manuel; García Benzaquén, Nerea; Martínez Alares, Irene; Navarro Gómez, Alejandro; Domínguez Rodríguez, Lucas José; García-Seco Romero, María TeresaPorcine brucellosis, caused by Brucella suis (B. suis), is a notifiable disease causing significant economic losses in production systems.Most infected pigsmay act as carriers and shed B. suis even if asymptomatic. This can contribute to environmental persistence, thus hindering control efforts. Here, the environment and the offspring were investigated during and after a B. suis outbreak at a sow breeding farm. The diagnosis of B. suis in sows (n = 1,140) was performed by culture and polymerase chain reaction (PCR) from vaginal swabs, indirect enzyme-linked immunosorbent assay (I-ELISA) from sera, and brucellin skin test (BST). B. suis diagnosis in post-weaning pigs (n = 899) was performed by I-ELISA in sera and BST. The environmental surveillance programme was implemented by placing gauze sponges (n = 175) pre-hydrated in a surfactant and inactivating liquid for Brucella DNA detection by PCR in different farm areas. Our results showed that the offspring of infected sows reacted to in vivo techniques for B. suis. Furthermore, the offspring born during the outbreak displayed higher seropositivity (I- ELISA) and reactivity (BST) than those pigs born after. Brucella DNA was detected in pregnant sow areas, boxes, boots, and post-weaning pig areas. In addition, Brucella DNA environmental detection was higher during the B. suis outbreak than the post B. suis outbreak. The environmental approach has proven to be a simple, practical, valuable, and safe method to detect and monitor B. suis. These results suggest a role of the environment and the offspring that should be considered in porcine brucellosis surveillance and control programmes.Item Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally(Frontiers in Veterinary Science, 2016) Pérez Sancho, Marta; Díez Guerrier, Alberto Antoine; Salinas, Jesús; Navarro Gómez, Alejandro; García Benzaquén, Nerea; Pozo Piñol, Pilar; Goyache Goñi, Joaquín; Álvarez, Julio; Domínguez Rodríguez, Lucas José; García-Seco Romero, María TeresaOvine enzootic abortion, caused by Chlamydia abortus, leads to important economic losses worldwide. In addition to reproductive failures, infection may impact lamb growth during the first weeks after birth, yet this effect has not been well characterized. Vaccination can help to control the disease but variable efficacy values have been described, possibly related with factors associated with the host, the vaccine, the parameter used for efficacy determination and the challenge conditions. In this context, we evaluated the efficacy of an inactivated standard commercial vaccine and a 1/2 diluted dose in pregnant sheep challenged with C. abortus by examining multiple indicators ofvaccine effect (including incidence of reproductive failures, bacterial excretion, and evolution of weight gain of viable lambs during the first month of life). Three groups of ewes [control non-vaccinated, C (n = 18); vaccinated with standard dose, SV (n = 16) and vaccinated with 1/2 dose, DV (n = 17)], were challenged approximately 90 days post-mating and tested using direct PCR (tissue samples and vaginal swabs) and ELISA (serum) until 31 days post-reproductive outcome. There were not significant differences in the proportions of reproductive failures or bacterial shedding after birth/abortion regardless the vaccination protocol. However, a beneficial effect of vaccination on offspring growth was detected in both vaccinated groups compared with the controls, with a mean increase in weight measured at 30 days of life of 1.5 and 2.5 Kg (p = 0.056) and an increase in the geometric mean of the daily gain of 8.4 and 9.7% in lambs born from DV and SV ewes compared to controls, respectively. Our results demonstrate the effect of an inactivated vaccine in the development of the offspring of C. abortus-infected ewes at a standard and a diluted dose, an interesting finding given the difficulty in achieving sufficient antigen concentration in the production of EAE-commercial vaccines.Item Evidence of Leishmania infantum infection in rabbits (Oryctolagus cuniculus) in a natural area in Madrid, Spain(BioMed Research International, 2014) García Benzaquén, Nerea; Moreno, Inmaculada; Alvarez, Julio; Cruz Conty, María Luisa; Navarro Gómez, Alejandro; Pérez Sancho, Marta; Conty, María Luisa; Toraño, Alfredo; Prieto, Antonio; Domínguez, Mercedes; Álvarez Sánchez, Julio; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio Manuel; García-Seco Romero, María TeresaLeishmaniasis is one of most important neglected zoonosis and remains endemic in at least 88 developing countries in the world. In addition, anthropogenic environmental changes in urban areas are leading to its emergency world-wide. Zoonotic leishmaniasis control might only be achieved by an integrated approach targeting both the human host and the animal reservoirs, which in certain sylvatic cycles are yet to be identified. Recently, hares have been pointed out as competent reservoirs of Leishmania infantum in Spain, but the role of other lagomorphs has not been clarified. Here, 69 rabbits (Oryctolagus cuniculus) from a natural area in Madrid in which a high density was present were analyzed using indirect (immunofluorescence antibody test, IFAT) and direct (PCR, culture) techniques. Fifty-seven (82.6%) of the animals were positive to at least one technique, with IFAT yielding the highest proportion of positive samples. L. infantum was isolated in 13% animals demonstrating the occurrence of infection in this setting. Our results suggest that rabbits could play a role of competent reservoir of L. infantum and demonstrate that the prevalence of infection is high in the analyzed area.Item Occurrence of Hepatitis E Virus in Pigs and Pork Cuts and Organs at the Time of Slaughter, Spain, 2017(Frontiers in Veterinary Science, 2020) García Benzaquén, Nerea; Marta Hernández; Maialen Gutierrez-Boada; Antonio Valero; Navarro Gómez, Alejandro; Milagros Muñoz-Chimeno; Fernández Manzano, Álvaro; Franco Matías Escobar; Martínez Alares, Irene; Bárcena Asensio, María Carmen; González Domínguez, Sergio; Ana Avellón; Jose M. Eiros; Gislaine Fongaro; Domínguez Rodríguez, Lucas José; Goyache Goñi, Joaquín; David Rodríguez-LázaroZoonotic hepatitis E, mainly caused by hepatitis E virus (HEV) genotype (gt) 3, is a foodborne disease that has emerged in Europe in recent decades. The main animal reservoir for genotype 3 is domestic pigs. Pig liver and liver derivates are considered the major risk products, and studies focused on the presence of HEV in pig muscles are scarce. The objective of the present study was to evaluate the presence of HEV in different organs and tissues of 45 apparently healthy pigs from nine Spanish slaughterhouses (50% national production) that could enter into the food supply chain. Anti-HEV antibodies were evaluated in serum by an ELISA test. Ten samples from each animal were analyzed for the presence of HEV RNA by reverse transcription realtime PCR (RT-qPCR). The overall seroprevalence obtained was 73.3% (33/45). From the 450 samples analyzed, a total of 26 RT-qPCR positive samples were identified in the liver (7/45), feces (6/45), kidney (5/45), heart (4/45), serum (3/45), and diaphragm (1/45). This is the first report on detection of HEV RNA in kidney and heart samples of naturally infected pigs. HEV RNA detection was negative for rib, bacon, lean ham, and loin samples. These findings indicate that pig meat could be considered as a low risk material for foodborne HEV infection.Item Liver Transudate, a Potential Alternative to Detect Anti-Hepatitis E Virus Antibodies in Pigs and Wild Boars (Sus scrofa)(Microorganisms, 2020) Navarro Gómez, Alejandro; Bárcena Asensio, María Carmen; Pozo Piñol, Pilar; Díez Guerrier, Alberto Antoine; Martínez Alares, Irene; Polo, Coral; Duque, Clara; Rodríguez-Lázaro, David; Goyache Goñi, Joaquín; García Benzaquén, NereaIn recent years, cases of hepatitis E virus (HEV) infection have increased in Europe in association with the consumption of contaminated food, mainly from pork products but also from wild boars. The animal’s serum is usually tested for the presence of anti-HEV antibodies and viral RNA but, in many cases such as during hunting, an adequate serum sample cannot be obtained. In the present study, liver transudate was evaluated as an alternative matrix to serum for HEV detection. A total of 125 sera and liver transudates were tested by enzyme-linked immunosorbent assay at different dilutions (1:2, 1:10, 1:20), while 58 samples of serum and liver transudate were checked for the presence of HEV RNA by RT-qPCR. Anti- HEV antibodies were detected by ELISA in 68.0% of the serum samples, and in 61.6% of the undiluted transudate, and in 70.4%, 56.8%, and 44.8% of 1:2, 1:10, or 1:20 diluted transudate, respectively. The best results were obtained for the liver transudate at 1:10 dilution, based on the Kappa statistic (0.630) and intraclass correlation coefficient (0.841). HEV RNA was detected by RT-qPCR in 22.4% of the serum samples and 6.9% of the transudate samples, all samples used for RT-qPCR were positive by ELISA. Our results indicate that liver transudate may be an alternative matrix to serum for the detection of anti-HEV antibodies.Item Hepatitis E en la cadena de producción porcina : de la granja a la mesa(2023) Navarro Gómez, Alejandro; García Benzaquén, Nerea; Barcena Asensio, Mª Carmen; Goyache Goñi, JoaquínEl virus de la Hepatitis E (VHE) es uno de los principales agentes causantes de hepatitis vírica aguda a nivel mundial, suponiendo un importante problema en Salud Pública. Pese a que su presentación es asintomática en la mayoría de los casos, se puede desarrollar una hepatitis aguda fulminante, sobre todo en mujeres gestantes. En los últimos años se ha observado que también es causante de hepatitis crónicas, principalmente en pacientes inmunodeprimidos o con enfermedades hepáticas previas. El VHE es el agente causal de la Hepatitis E (HE), virus que pertenece al género Ortohepevirus y que actualmente está conformado por 8 genotipos distintos conocidos. Los genotipos que afectan, principalmente, al ser humano son los genotipos 1-4, aunque se ha descrito el posible potencial zoonósico de los genotipos 5, 7 y 8. Cada uno de estos genotipos se asocian a distintas, aunque no excluyentes, zonas geográficas, distinguiéndose diferentes escenarios epidemiológicos. De este modo, en los países envías de desarrollo los principales genotipos que se detectan son el 1 y el 2, y la HE se presenta primordialmente en forma de grandes brotes epidémicos como consecuencia del consumo de aguas con contaminación fecal. Por otra parte, en los países desarrollados predominan los genotipos 3 y 4, que suelen producir brotes esporádicos, generalmente asociados al consumo de alimentos contaminados insuficientemente cocinados...