J F García Marín

Spanish National Research Council, Madrid, Madrid, Spain

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Publications (51)95.15 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The two main genotypes of recognized isolates of Mycobacterium avium subsp. paratuberculosis (Map) are cattle (C) and sheep (S) strains. An experimental infection was conducted to establish the effect of Map strain on the pathogenesis of ovine paratuberculosis. Twenty-four out of thirty 1.5-month-old Assaf lambs were divided into 4 groups of 6 and infected orally with three low passage field isolates, two of S- (22G and the pigmented Ovicap49) and one of C- (764) type, and the reference K-10 strain (C type). The remaining six animals were unchallenged controls. Animals were euthanized at 150 and 390 days post-infection (dpi). Throughout the experiment, the peripheral immune response was assessed and histological and molecular (PCR) studies were conducted on samples of intestine and related lymphoid tissue. Specific antibody and IFN-gamma production was significantly higher in animals infected with the C strains, while no consistent IFN- gamma responses were observed in the S-type strain infected groups. A positive intradermal skin test response was detected in all infected groups. Lambs infected with S-type strains had granulomatous lesions restricted to the lymphoid tissue with no differences in the lesion intensity over time. In both C-type strain groups, lesions were more severe at 150 dpi while at 390 dpi lesions, characterized by well-demarcated granulomas with fibrosis, decreased in severity. Only infected lambs were positive to PCR. These results suggest that the strain of Map has a strong influence over the immune and pathological responses developed by the host. Lesions induced by C-type strains in lambs show a regressive character and tend to decrease as the infection progresses.
    Veterinary Research 01/2014; 45(1):5. · 3.43 Impact Factor
  • A Balseiro, L J Royo, A Gómez Antona, J F García Marín
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    ABSTRACT: Between January and June 2013, nine stillborn bovine foetuses with congenital malformations from nine cattle herds located in Salamanca (central Spain) were detected. Necropsy was performed on two calves. Pathological lesions together with molecular genetics and serological results allowed a definitive diagnosis: first confirmation of Schmallenberg virus (SBV) infection in cattle in Spain. SBV was detected in different tissues and organic fluids in both animals including blood, suggesting a possible viraemia. The umbilical cord was also positive for the presence of SBV in both animals. The former tissue provides an easy to obtain sample and might be a sample of choice when necropsy is carried out in the field.
    Transboundary and Emerging Diseases 11/2013; · 2.10 Impact Factor
  • Ana Balseiro, Luis J. Royo, Antonio Gómez Antona, Juan F. García Marín
    SEAPV. 10/2013;
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    ABSTRACT: Abstract Clostridium sordellii is found in the environment and occasionally in animal (including human) intestines and may cause myonecrosis and large outbreaks of enterotoxemia. A few cases of fatal clostridial infection in bears (Ursus spp.) have been described worldwide but none attributed to C. sordellii. We describe a fatal case of septicemia caused by C. sordellii in an illegally trapped brown bear (Ursus arctos). At necropsy, acute gangrenous myositis was the primary lesion. Serohemorrhagic edema was observed in the abdominal cavity, thorax, pericardium, and skeletal muscle, mostly affecting femoral, humeral, and scapular muscles. Hemorrhage was observed in the heart, skeletal muscles, stomach, and intestine. Liver, spleen, and kidney appeared with loss of consistency, hemorrhages, and edema. Microscopically, primary lesions were in skeletal muscle, stomach, and small intestine, with gram-positive, clostridial-like bacilli. Biochemical and molecular tests identified C. sordellii in cultures from liver, muscle, and intestine. Sequences showed a homology of >99% with the 16S rRNA gene sequence of C. sordellii. The severity of effects of the C. sordellii infection reveal the importance of this pathogen as a wildlife health risk with conservation concerns, as well as the need to consider possible infection with this pathogen in management actions involving immobilization, stress, or severe muscular activity of wild brown bears.
    Journal of wildlife diseases 10/2013; 49(4):1047-51. · 1.27 Impact Factor
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    ABSTRACT: The aim of this work was to study a retrospective case series of acute degenerative myopathy, which caused high mortality in adult horses grazing in a specific region of Spain, in relation to a possible etiopathogenesis. Outbreaks of myopathy occurred in December of 1999, 2003, 2009, and 2011 after an abrupt fall in temperatures and the first snowfalls. Ten horses were necropsied, and an exhaustive gross and histopathological examination was performed using specific histochemical stainings to evaluate muscle and cardiac damage. Intense myodegeneration, affecting the postural and respiratory muscles and the muscles involved in swallowing, was the main finding. A further consistent finding was necrosis of Purkinje fibers in the myocardium. Serum concentration values of creatine kinase, selenium, and vitamin E, as well as blood concentration values of glutathione peroxidase activity, were determined in 10 horses clinically affected and in another 12 horses with no clinical signs. In the affected horses, creatine kinase was high and reached values over 10,000 U/L. Selenium values were deficient in the horses affected, ranging from 4.2 to 10.5 μg/g (reference range: >50 μg/L) in selenium-untreated horses, and also, selenium values in 11 horses with no clinical signs were below the reference range. Glutathione peroxidase activity was below the reference range in all the analyzed sera, and vitamin E values were also below the reference range in four horses. The severe selenium deficiency together with a sudden arrival of unfavorable weather conditions seemed to provoke the arising of this disease. The presence of Eupatorium cannabinum in this valley is discussed as a possible source of the phytotoxin associated with rhabdomyolysis.
    Journal of Equine Veterinary Science 06/2013; 33(6):475–482. · 0.62 Impact Factor
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    ABSTRACT: Maedi-visna (MV) is a slow lentiviral disease of sheep that has a significant economic impact in many sheep-producing regions although there remains a paucity of data relating to actual production losses resulting from this disease. The objective of this study was to evaluate direct losses, through death or culling, from two dairy sheep flocks with high seroprevalences of infection over a 2year period. Maedi-visna was found, either alone or in combination with other diseases, to be the most common disease diagnosed in these sheep, and the major cause of direct animal losses in the two flocks. Moderate to severe lesions associated with MV were found in 52% and 80% of the sheep, respectively, affecting the lungs, brain and/or mammary glands. Despite the similarity of the two flocks under study in terms of breed, number of animals, geographical proximity, and inter-change of rams, a striking difference was observed regarding the clinical presentation of the disease: in one flock the respiratory form was dominant while in the other 70% of animals died or were culled because of neurological signs.
    The Veterinary Journal 05/2013; · 2.42 Impact Factor
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    ABSTRACT: Mycobacterium avium subsp paratuberculosis (Map) is assumed to infect young ruminants; however, little is known concerning the possibility of adult animals becoming infected. An experimental infection was conducted to establish the effect of age and doses of Map on susceptibility to paratuberculosis in sheep. Sixteen of twenty-four 1.5-month-old Churra lambs and 23 of 30 adult ewes (from 2-11 years old) were orally challenged with an ovine field strain of Map. Thirteen ewes and 8 lambs were infected with a high dose (HD) and 10 adult sheep and 8 lambs with a low dose (LD) of Map. The remaining animals were unchallenged controls. Animals were euthanized at 110 to 120 and 210 to 220 days postinfection. Histological, bacteriological, and nested polymerase chain reaction (PCR) studies were conducted in samples of intestine and related lymphoid tissue (Peyer patches, lymph nodes). Animals were classified according to their lesions. The number of granulomas was counted in 3 tissue sections from each sample. Only the HD groups showed lesions associated with paratuberculosis (92.3% of ewes and 100% of lambs). Adults had lesions characterized by few small demarcated focal granulomas restricted to the lymphoid tissue, whereas granulomas were more numerous and larger, appearing in the lamina propria unrelated to lymphoid tissue, in the lambs. Only HD-infected lambs were positive to culture, whereas nested PCR also detected positive HD ewes and some LD animals. These results suggest that adult sheep can become infected by Map, as seen by the development of lesions, but they are focal and restricted to the lymphoid tissue.
    Veterinary Pathology 02/2013; · 1.93 Impact Factor
  • Journal of Comparative Pathology 01/2013; 148(1):57. · 1.38 Impact Factor
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    ABSTRACT: We examined the distribution in the perivascular spaces of Visna/maedi antigen, T cells (CD3+, CD4+ and CD8+), B cells and macrophages by immunohistochemistry in 22 natural cases of Visna/maedi encephalitis. Sheep showed lymphocytic or histiocytic lesions. In mild lymphocytic lesions, the viral antigen was detected in perivascular cuffs where CD8+ T cells predominated, but in severe lymphocytic lesions, sparse antigen was identified, and CD8+/CD4+ T cells appeared in a similar proportion in multilayer perivascular sleeves. In histiocytic lesions, vessels were surrounded by macrophages with abundant viral antigen, with CD8+/CD4+ T cells and B cells in the periphery. These results could reflect different stages of virus neuroinvasion and clarify the neuropathogenesis of Visna/maedi encephalitis.
    Journal of NeuroVirology 10/2012; · 2.85 Impact Factor
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    ABSTRACT: Although louping ill affects mainly sheep, a 2011 outbreak in northern Spain occurred among goats. Histopathologic lesions and molecular genetics identified a new strain of louping ill virus, 94% identical to the strain from Britain. Surveillance is needed to minimize risk to domestic and wildlife species and humans.
    Emerging Infectious Diseases 06/2012; 18(6):976-8. · 6.79 Impact Factor
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    ABSTRACT: The present study records recurrent outbreaks of myelodysplasia of unknown origin occurring in a specific geographical location in the north of Spain, and involving up to 30% of the calves born in affected herds. The affected calves were of different breeds and displayed non-progressive signs of spinal cord dysfunction. The disease has occurred annually in February-March over a period of at least 15 years. Only calves born to cattle grazed on mountainside pastures and under high grazing pressure were affected. Seven calves were subjected to necropsy examination. Myelodysplasia was not associated with vertebral defects or arthrogryposis and involved the entire length of the spinal cord. Microscopically, there was abnormal distribution of the grey matter, aberrations of the central canal and failure of formation of the ventral median fissure. Infectious, nutritional and physical disorders were ruled out as possible aetiologies. A critical period of embryonic susceptibility to the causal agent was identified. This was during the time of secondary neurulation when cows in the early stages of gestation were grazed on mountainside pastures. Consequently, the presence of neuroteratogenic plants in these pastures is proposed as a likely cause. Two plants, Carex brevicollis and Erythronium dens-canis, which contain alkaloids, were identified on the mountainsides where affected cattle were grazed and not in other pastures, and are proposed as the possible aetiology of the disease.
    Journal of comparative pathology 04/2012; · 1.73 Impact Factor
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    ABSTRACT: The peripheral immune response, and its relationship with the outcome of the infection according to the age of the animal, has been investigated in young lambs and adult ewes experimentally infected with two different doses of Mycobacterium avium subspecies paratuberculosis (Map). Sixteen 1.5-month-old lambs out of 24 and 23 adult ewes out of 30 were orally challenged with an ovine Map field isolate. Animals were divided into two groups: HD, infected with a higher dose of Map and LD, with a lower dose. The remaining animals were used as uninfected control groups. Animals were euthanized at 110-120 and 210-220 days post-infection (dpi). Along the experiment, the humoral response and the specific and non-specific IFN-γ production were assessed. An intradermal skin test (IDT), using avian PPD, was also performed at 90 and 195 dpi. Samples of intestine and related lymphoid tissue were taken for histological, bacteriological and PCR studies. The Ab and IFN-γ production as well as the IDT response appeared earlier and with more intensity in the adult ewes compared to the lambs. The basal non-specific IFN-γ levels increased only in the adult ewes from the HD group. Animals from the LD and HD groups were positive to PCR; however, lesions consistent with paratuberculosis were exclusively observed in the HD group, both in lambs and in adult sheep, but they only progressed to more advanced stages in the former. These results suggest that the peripheral immune response induced by Map infection in the adult ewes is more efficient to control the progression of the infection than in lambs. This could likely be due to the existence of previous contacts with Map or other mycobacteria in the adult sheep compared to the young lambs.
    Veterinary Immunology and Immunopathology 10/2011; 145(1-2):23-31. · 1.88 Impact Factor
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    ABSTRACT: This study investigates the nervous form of ovine maedi-visna by histological and immunohistochemical techniques. The aim was to study the lesion types and the local cellular immune response related to each lesion type, and the possible relationship between these parameters. Thirty-four Assaf ewes were studied, 29 of which had shown nervous signs. Microscopical lesion patterns were described according to location, extent and predominance of inflammatory cell type. Immunohistochemical labelling of T cells (CD3(+), CD4(+), CD8(+) and cells expressing the γδ form of the T-cell receptor), B cells and macrophages revealed clear differences between the lesion patterns. Two main lesion types were described. Lymphocytic lesions had areas of mild-moderate injury characterized by a predominance of infiltrating T cells. Histiocytic lesions were more severe and had extensive areas of malacia and dominant infiltration by macrophages and B cells. Each animal had a unique lesion pattern and these differences could be due to individual resistance to the progression of infection. The lymphocytic lesions appear to represent initial or latent phases of slow progression, in which the animal presents some natural resistance to the infection. The histiocytic pattern may reflect a poor immune response or a greater virulence of the viral strain.
    Journal of comparative pathology 10/2011; 147(1):1-10. · 1.73 Impact Factor
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    ABSTRACT: Tuberculosis was diagnosed in three flocks of sheep in Galicia, Spain, in 2009 and 2010. Two flocks were infected with Mycobacterium bovis and one flock was infected with Mycobacterium caprae. Infection was confirmed by the comparative intradermal tuberculin test, bacteriology, molecular analysis and histopathology. Sheep have the potential to act as a reservoir for tuberculosis.
    The Veterinary Journal 06/2011; 191(2):267-9. · 2.42 Impact Factor
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    ABSTRACT: Dystrophic epidermolysis bullosa (DEB) was diagnosed in five newborn Assaf lambs from a flock in which around 1-2% of the lambs were lame. Affected animals had marked erythema of the coronary band and subsequent detachment of the hooves. Blisters were present on the lips and in the oral and oesophageal mucosae. Erosions and crusts were noted in the axillary and inguinal areas. Microscopically, there was detachment of the epidermis from the dermis. The roof of these bullous spaces was formed by the intact epidermis with its basement membrane. The bullae were generally filled with pale eosinophilic proteinaceous fluid and erythrocytes. Immunohistochemical analysis revealed absence of collagen VII in the basement membrane zone. The disease in these lambs appears similar to the severe recessive form of human DEB.
    Journal of comparative pathology 02/2011; 145(2-3):226-30. · 1.73 Impact Factor
  • Journal of Comparative Pathology - J COMP PATHOL. 01/2010; 143(4):346-346.
  • Journal of Comparative Pathology 11/2009; 141(4):270-270. · 1.38 Impact Factor
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    The Veterinary record 05/2009; 164(15):468-70. · 1.80 Impact Factor
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    ABSTRACT: To evaluate the degree of endothelialization of the nonapposed struts located at the ostia of side branches. Endothelialization of coronary stents has got considerable relevance because of the phenomenon of late thrombosis. Bifurcation location and incomplete stent apposition have been linked to this complication. Domestic pigs (n = 11; weight: 25 +/- 3 kg) were anesthetized and had one stent per coronary artery implanted: one stainless steel (Tecnic), one cobalt-chromium (Chrono), and one tacrolimus-eluting stent (Janus), all of them being Carbofilm-coated (Sorin). One, three, or seven days postprocedure, the pigs were sacrificed, the hearts explanted, and longitudinal sections examined by surface electron microscopy to quantify the percentage of the strut endothelialized over the branches and in the total surface. Forty-four side branches (25 stents) that had stent struts over their origin were evaluated. Different patterns of endothelialization were observed, from the total absence to the complete endothelialization. There were no significant differences in relation to type of stent or to the artery treated. The predictors of higher percentage of endothelialization were the ratio of metal to branch diameter (P = 0.04) and better endothelialization in the rest of the stent (P = 0.0002), only this parameter maintaining significant correlation (P = 0.03) in multivariate analysis. Carbofilm-coated stent struts located over the origin of side branches follow the pattern of endothelialization for the rest of the stent, even in the case of tacrolimus-eluting stent.
    Journal of Interventional Cardiology 04/2009; 22(3):222-7. · 1.50 Impact Factor
  • A Balseiro, J F García Marín, P Solano, J M Garrido, J M Prieto
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    ABSTRACT: Ninety-five adult fallow deer, legally hunted in the Regional Hunting Reserve of El Sueve (Northern Spain), were subjected to a post-mortem examination for paratuberculosis, samples being taken from the proximal and distal jejunum, proximal and distal ileum, ileocaecal valve and associated lymph nodes. The lesions were divided into four categories. Focal lesions (n=19 cases) consisted of small granulomas, mainly in the jejunal and ileal lymph nodes. Multifocal lesions (n=4) consisted of well-demarcated granulomas in the intestinal lymphoid tissue and also in the intestinal lamina propria. Diffuse multibacillary lesions (n=2) were characterized by a severe granulomatous enteritis and lymphadenitis. Macrophages and numerous Langhans giant cells containing many mycobacteria were present, resulting in macroscopical changes in the normal gut morphology. These changes were found from the proximal jejunum to the ileocaecal valve, but lesions were always particularly severe in the distal jejunum. In diffuse intermediate (multibacillary-lymphocytic) lesions (n=3) the infiltrate consisted of lymphocytes, macrophages and Langhans giant cells, with small numbers of mycobacteria. Mycobacterium avium subspecies paratuberculosis was identified by a polymerase chain reaction technique. The widespread occurrence of paratuberculosis in fallow deer in this Reserve represents a potential source of infection for other susceptible species.
    Journal of Comparative Pathology 06/2008; 138(4):180-8. · 1.38 Impact Factor

Publication Stats

715 Citations
95.15 Total Impact Points


  • 2013
    • Spanish National Research Council
      Madrid, Madrid, Spain
  • 2003–2013
    • Servicio Regional de Investigación y Desarrollo Agroalimentario
      Asturias, Spain
  • 1998–2013
    • Universidad de León
      • • Facultad de Veterinaria
      • • Department of Animal Health
      León, Castile and Leon, Spain
  • 1991–1997
    • University of Zaragoza
      • • Faculty of Veterinary
      • • Patología Animal
      Zaragoza, Aragon, Spain