Person: Rebollada Merino, Agustín Miguel
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First Name
Agustín Miguel
Last Name
Rebollada Merino
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Veterinaria
Department
Medicina y Cirugía Animal
Area
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11 results
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Item Detection of Brucella in Dermacentor Ticks of Wild Boar with Brucellosis(Transboundary and Emerging Diseases, 2024) Rebollada Merino, Agustín Miguel; Martínez Alares, Irene; Duque, Clara; García-Seco Romero, María Teresa; Escacena, Cristina; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio Manuel; García Benzaquén, Nerea; Daniel DiazBrucellosis is a sanitary and economically relevant disease affecting humans, livestock, and wildlife. Ticks have been suggested as vectors, long-term carriers, and amplifiers of Brucella. In this study, ticks from wildlife ungulate hosts living in hunting reserves of a central region of Spain were collected during a 6-year period, pooled, and screened for Brucella spp. by PCR. Aiming to correlate Brucella spp. DNA presence in ticks with Brucella spp. infections in wildlife ungulate hosts, liver samples from deceased wildlife ungulates coming from the hunting reserves showing a positive result for Brucella in ticks were tested using a commercial ELISA. In total, 229 tick pools from wild boar (Sus scrofa, n = 176; 76.8%, 95% CI 70.9%–81.8%), red deer (Cervus elaphus, n = 40; 17.4%, 95% CI 13.1%–22.9%), mouflon (Ovis orientalis musimon, n = 7; 3.06%, 95% CI 1.49%–6.17%), and fallow deer (Dama dama, n = 6; 2.62%, 95% CI 1.21%–5.60%) were analyzed. PCR results showed that 3.93% (95% CI 2.08%–7.30%) tick pools (9/229) from 16.6% hunting reserves (7/41) screened yielded a positive PCR result for Brucella. All positive ticks were Dermacentor (Dermacentor marginatus or Dermacentor reticulatus) collected from wild boar. Ticks collected from wild boars were positive to Brucella in a relative percentage of 5.10% (95% CI = 1.61–11.4) in 2018 and of 7.59% (95% CI = 2.79–15.6) in 2021 (6-year prevalence of 5.17%, 9/176). ELISA showed positive results in three wild boars coming from two out of seven hunting reserves (28.5%) with a positive PCR for Brucella in ticks. To conclude, Brucella spp. DNA can be detected in Dermacentor ticks parasitizing wild boars living in hunting reserves harboring Brucella spp.-seropositive wild boars. This study provides evidence that the contribution of arthropod vectors should be considered in the epidemiology of brucellosis in wildlife.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 Animal abuse in Spanish-breed fighting cocks (Gallus gallus domesticus)(Forensic Science International: Animals and Environments, 2022) Rebollada Merino, Agustín Miguel; Bárcena Asensio, María Carmen; Barreno San Antolín, Lucía; Pizarro Díaz, Manuel; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelCockfighting is illegal both in the European Union and the United States, although fighting cock husbandry and breed preservation are allowed. Here, we describe the pathological findings observed in the carcasses of two Spanish-breed fighting cocks submitted to our laboratory after an animal abuse-suspected death. The postmortem examination revealed these cocks may have been used for cockfighting (comb, ear lobes, wattles, and chest feather removal; and trimmed spurs). The severe extensive hemorrhages observed in the cervical region of both birds, affecting C1-C4 in bird No. 1 and C8-C11 in No. 2, suggested cervical dislocation in a non-professional manner. To the best of our knowledge, this is the first report of abuse in a Spanish-breed fighting cock. The aim of this paper is to contribute to the identification of animal abuse cases in avian species which may lead to successful prosecutions in Spain and elsewhere.Item Forensic findings in urban red fox mortality in the metropolitan area of Madrid, 2014–2022(Journal of Veterinary Diagnostic Investigation, 2024) Rebollada Merino, Agustín Miguel; Bárcena Asensio, María Carmen; Porras González, Néstor; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelThe expanding presence of red foxes ( Vulpes vulpes) in urban and suburban regions could potentially lead to increased instances of human aggression towards this species. We studied 10 deceased red foxes that were submitted by law enforcement agencies in the metropolitan area of Madrid in 2014–2022 because of suspected abuse. Forensic autopsies were performed to establish the cause and manner of death. In 4 of the 10 cases, the cause of death was deemed unnatural, involving blunt-force trauma ( n = 2), asphyxia resulting from hanging ( n = 1), and firearm injury ( n = 1). Among the remaining cases, most had succumbed to natural causes ( n = 4), often marked by severe emaciation and a high burden of parasites, primarily Sarcoptes scabiei. In 2 cases, death was undetermined given the poor preservation of the carcass. The growing prevalence of wildlife species in urban areas, particularly red foxes, may require forensic veterinary investigation of deaths potentially related to abuse.Item Forensic investigations of suspected livestock depredation by vultures: scientific tools for compensation programmes(Journal of Comparative Pathology, 2024) Rebollada Merino, Agustín Miguel; Gómez-Buendía, Alberto; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelHuman–wildlife conflicts may have devastating consequences for fauna due to targeting by humans of wildlife populations suspected to have predated livestock. Suspicion of depredation of extensively raised livestock by vultures in Europe has triggered public administration-led forensic investigations intended to distinguish between predation and scavenging in order to compensate farmers for attacks on their livestock. In this study, gross and histological analyses were carried out on suspected cases of domestic animal depredation by griffon vultures (Gyps fulvus) over a 1-year period. Fifty-eight animals were affected (n = 41, suspected depredation), including domestic cattle (75.9%), sheep (22.4%) and a goat (1.7%). All the adults affected were female and most cases of suspected depredation occurred during the peripartum period (56%). Histological investigations distinguished between post-mortem (84% of diagnostic samples) and ante-mortem (16% of diagnostic samples) cases, and gross examinations revealed significant differences (P ≤ 0.002) between ante-mortem, post-mortem and non-diagnostic samples. This study highlights the need to optimize sampling protocols to increase the success of forensic studies. The forensic investigations presented here may be applied to resolve human–wildlife conflicts involving not only vultures but other endangered carnivores and contribute to human–wildlife coexistence in rural areas by protecting the interests of both the livestock sector and endangered species.Item Cecal Reduction of Brachyspira and Lesion Severity in Laying Hens Supplemented with Fermented Defatted ‘Alperujo’(Fermentation, 2022) Rebollada Merino, Agustín Miguel; Ugarte Ruiz, María; Alberto Gómez-Buendía; Bárcena Asensio, María Carmen; García Benzaquén, Nerea; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelAntimicrobial resistance demands the development of therapeutic alternatives such as prebiotics, probiotics, and nutraceuticals. The aim of this study was to assess the antimicrobial proprieties of the nutraceutical fermented defatted “alperujo”, derived from olive oil production, in a laying hen farm (n = 122,250) endemic with avian intestinal spirochetosis (Brachyspira spp.). Part of the batch (n = 1440) was divided into six groups of 240 hens each that included 80 or 108-week-old laying hens, supplemented with 0%, 2%, or 6% fermented defatted ‘alperujo’ for a month. At the end of the experiment, eight hens from each group were autopsied and cecal content was subjected to (i) Brachyspira culture and species identification by PCRs, and (ii) direct DNA extraction and Brachyspira qPCR. Furthermore, the ceca were processed for histopathology. Microbiological isolation revealed B. pilosicoli and B. hyodysenteriae co-infection in all groups. The 80-week-old hen group 2% supplemented showed a reduction in the cecal Brachyspira content (qPCR) compared with non-supplemented hens. Cecal histopathology showed a diffuse mild infiltration of lymphocytes, plasma cells, and heterophils; and hyperplasia of the gut-associated lymphoid tissue hyperplasia which decreased in severity in 80-week-old supplemented hens. The reduction in Brachyspira colonization and the severity of the lesions observed in supplemented hens highlights a potential protective function against avian intestinal spirochetosis.Item An Outbreak of Aeromonas salmonicida in Juvenile Siberian Sturgeons (Acipenser baerii)(Animals, 2023) Vázquez Fernández, Esther; Chinchilla Rodríguez, Blanca; Rebollada Merino, Agustín Miguel; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelAeromonas salmonicida is one of the major threats to world aquaculture, causing fish furunculosis and high mortality rates in cultured fish, particularly salmonids. Although Aeromonas spp. is a thoroughly studied pathogen, little is known regarding aeromoniasis in sturgeons. After a mortality outbreak, four juvenile sturgeons (Acipenser baerii) were submitted for autopsy and tissue samples were collected for histopathological and microbiological studies. The external examination revealed size heterogenicity, skin hyperpigmentation and reduced body condition of sturgeons. Within the abdominal cavity, mild hepatomegaly and splenomegaly were observed, as well as generalized organic congestion. Histology revealed severe multifocal haemorrhagic and ulcerative dermatitis, mainly localized in the dorsal and latero-ventral areas of fish. The histological study also showed moderate to severe inflammation of gills and organic lesions compatible with septicaemia. Bacterial isolates were identified as Aeromonas salmonicida subsp. salmonicida using MALDI-TOF MS and PCR. Overall, the lesions first described here are consistent with those previously reported in other cultured fish species and contribute to a better understanding of the pathogenesis of Aeromonas salmonicida subsp. salmonicida in the Siberian sturgeon, aside from providing new diagnostic tools for bacterial diseases impacting the fast-growing industry of caviar.Item Histopathologic and immunohistochemical findings in the placentas and fetuses of domestic swine naturally infected with Brucella suis biovar 2(Journal of Veterinary Diagnostic Investigation, 2023) Rebollada Merino, Agustín Miguel; García-Seco Romero, María Teresa; Pérez Sancho, Marta; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelPorcine brucellosis, which is caused by Brucella suis biovar (bv) 2, is a re-emerging disease that causes reproductive problems in pigs in Europe. The pathogenesis and lesions of B. suis intrauterine infection are poorly characterized; characterization could facilitate the diagnosis and investigation of porcine brucellosis. We collected samples of placentas and fetuses for histologic and microbiologic studies during an outbreak of abortions on a pig-breeding farm in Spain. Brucella was cultured from the vaginal swabs obtained from sows that had aborted, some placentas, and fetal tissues (spleen, liver, lung, gastric content); molecular testing confirmed B. suis bv 2 infection. Histologically, there was necrotizing and hemorrhagic placentitis; suppurative hepatitis; lymphoid depletion and sinusoidal histiocytosis in the spleen, lymph nodes, and thymus; and bronchointerstitial pneumonia. Hemorrhages were observed in the umbilical cord, heart, kidneys, and brain. We detected Brucella by immunohistochemistry (IHC) in all of the placentas and fetal organs studied, specifically in the trophoblasts of the chorionic epithelium, in the cytoplasm of macrophages in the chorionic stroma, and extracellularly in necrotic debris. Furthermore, we assessed the lymphocyte population in the placentas through the use of IHC (anti-CD3, anti- Pax5 antibodies), revealing that the lymphocytic response was composed of T cells but not B cells.Item First detection of Flavobacterium psychrophilum in juvenile Siberian sturgeons (Acipenser baerii) and description of the pathological findings(Journal of Fish Diseases, 2023) Chinchilla Rodríguez, Blanca; Vázquez Fernández, Esther; Rebollada Merino, Agustín Miguel; Pérez Sancho, Marta; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelFlavobacterium psychrophilum affects many cultured fish species and is considered one of the most important bacterial pathogens causing substantial economic losses in salmonid aquaculture worldwide. Here, F. psychrophilum was identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nested PCR as the aetiological agent causing mortality in diseased juvenile Siberian sturgeons (Acipenser baerii) reared on a freshwater fish farm. Diseased sturgeons were lethargic and displayed dark skin pigmentation, increased mucus production and the presence of skin ulcerations and haemorrhages specially on the ventral side and the base of fins. The histological examination of fish revealed proliferative branchitis, ulcerative and necrotizing dermatitis and myositis, lymphoid tissue atrophy, liver and kidney degeneration and thrombosis. To the best of our knowledge, this is the first report describing the infection of Siberian sturgeons by F. psychrophilum. The detection of F. psychrophilum in diseased Siberian sturgeons and the description of the pathological findings observed during the outbreak may contribute to a better understanding of the bacterium pathogenicity and the range of fish species susceptible to infection.Item Immunopathology of early and advanced epididymis lesions caused by Brucella ovis in rams(Veterinary Immunology and Immunopathology, 2023) Rebollada Merino, Agustín Miguel; García-Seco Romero, María Teresa; Chinchilla Rodríguez, Blanca; Pérez Sancho, Marta; Domínguez Rodríguez, Lucas José; Rodríguez Bertos, Antonio ManuelOvine brucellosis is an infectious disease that causes alterations in the reproductive tract in ram and abortion in ewes. Their negative economic impact in ovine production warrants a thorough understanding the interactions between B. ovis and the host. Here, epididymis lesions of rams infected by B. ovis were histopathologically staged into early and advanced. Expression by immunohistochemistry of Brucella antigens, inflammatory cell markers (CD3, CD79αcy) and cytokines (IFN-γ, TNF-α, TGF-β1) was assessed in both stages. Early lesions were characterized by epithelial changes, interstitial inflammation, and mild fibrosis; whereas advanced lesions displayed caseous granulomas containing numerous macrophages, multinucleated giant cells, lymphocytes, and plasma cells. Expression of Brucella antigens were observed in both stages. The cellular response in B. ovis lesions were predominantly of T-cells (CD3+) whereas low numbers of B-cells and plasma cells (CD79αcy+) were present in both early and advanced lesions. IFN-γ was expressed by lymphocytes in early lesions suggesting that the adaptive immune response against B. ovis is initiated by Th1 cells, this response was also preserved in advanced stages. Expression of TNF-α was observed in neutrophils of epithelial microabscesses and intraepithelial T-cells of early lesions suggesting a promotion of neutrophil phagocytosis triggered by TNF-α. On the other hand, advanced lesions showed a reduction of TNF-α expression which may permit B. ovis persistence in granulomas. Lastly, TGF-β1 expression (fibroblast, macrophages and less in lymphocytes) were increased with time, suggesting that B. ovis promotes TGF-β1 secretion promoting chronicity of the lesions.