Jorge Arturo Fernández-Silva

University of Antioquia, Medellín, Antioquia, Colombia

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Publications (6)3.86 Total impact

  • Jorge Arturo Fernández-Silva · Nathalia María Correa-Valencia · Nicolás Fernando Ramírez
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    ABSTRACT: Mycobacterium avium subsp. paratuberculosis causes paratuberculosis or Johne's disease (JD) in domestic ruminants and wild species. The aim of the present study was to systematically review the prevalence of paratuberculosis among farmed animals (cattle, sheep, and goats) in Latin America and the Caribbean. The initial search for existing publications reporting systematic reviews and primary studies was carried out by searching the available databases. For the final selection of studies, an initial screen for basic eligibility and a detailed appraisal of quality were performed. After study selection, the relevant data were extracted. The detailed appraisal generated 24 publications that reported 52 studies, of which 73.1, 11.5, and 15.4 % were from cattle, sheep, and goats, respectively. Thirty-three (63.5 %) of the studies were animal level studies, while 19 (36.5 %) were herd-/flock-level studies. No flock-level studies on prevalence in sheep were found. Studies in Latin American and Caribbean countries revealed an overall prevalence of 16.9 (95 % CI (confidence interval) 13.2-20.5) and 75.8 % (95 % CI 50.1-101.5) in cattle at the animal and herd levels, respectively; the prevalence was 16 % (95 % CI 7.9-24.1) in sheep at the animal level and 4.3 % (95 % CI 1.9-6.8) and 3.7 % (95 % CI 0.1-7.4) in goats at the animal and flock levels, respectively. In general, prevalence results reported by the studies were insufficient to accurately determine the prevalence of paratuberculosis in farmed animals in Latin America and the Caribbean. Several flaws in the design of studies limit the quality of evidence regarding the prevalence of paratuberculosis in the region.
    No preview · Article · Aug 2014 · Tropical Animal Health and Production
  • Jorge Arturo Fernández-Silva · Amir Abdulmawjood · Ömer Akineden · Michael Bülte
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    ABSTRACT: Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of Johne's disease or paratuberculosis of ruminants and has been associated with Crohn's disease in humans. In this study, the genotypes of MAP obtained so far in South American countries using a combination of the subtyping methods Mycobacterial Interspersed Repeats Units-Variable Number of Tandem Repeats (MIRU-VNTR) and Multilocus Short Sequence Repeats (MLSSR) were analyzed. Through this analysis, seven different MIRU-VNTR genotypes and seven MLSSR genotypes have been detected. If both methods were combined, nine different genotypes were found. Results revealed the predominance of MIRU-VNTR genotype 1 (INMV 1) and MLSSR genotype A (7 g-10 g-4ggt) among MAP isolates from different host species in South America. These predominant MAP genotypes are also commonly detected in Europe and the United States. This predominance could be the result of higher animal infection ability or better culturability on solid media used for isolation. Further studies on molecular epidemiology of MAP must be carried out in South America to increase our knowledge of the global distribution of MAP.
    No preview · Article · Feb 2012 · Tropical Animal Health and Production
  • J.A. Fernández-Silva · A Abdulmawjood · Ö Akineden · K Dräger · W Klawonn · M Bülte
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    ABSTRACT: Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of Johne's disease in dairy cattle. Genotyping of MAP is useful to gain a better understanding of the origin of infection, to evaluate regional control programs, to improve diagnostics, and to develop vaccines. In this study 91 MAP isolates mainly from symptomatic dairy cattle in Rhineland-Palatinate (RP, Germany), its neighbor federal states, and Luxembourg were genotyped using Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeat (MIRU-VNTR) and Multilocus Short Sequence Repeats (MLSSR). MIRU-VNTR and MLSSR produced 11 and 6 different genotypes among the 91 isolates, respectively. The combined analysis of both methods produced 25 genotypes with an index of discrimination (D) of 0.93 (95% CI: 0.91-0.95). The results revealed the genetic diversity of MAP and the dominance of two MAP genotypes commonly found in Europe, showed the usefulness of MAP genotyping in studies at a regional scale, and provided useful information for control initiatives in RP.
    No preview · Article · Jan 2012 · Research in Veterinary Science
  • Ö. Akineden · J.A. Fernández-Silva · S. Weirich · A. Abdulmawjood · M. Bülte
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    ABSTRACT: Mycobacterium avium subsp. paratuberculosis (MAP) has been suggested as a possible cause of Crohn's disease (CD) in humans, which is a chronic granulomatous ileocolitis that typically affects young adults. Milk and meat are considered source of MAP exposure to humans. Depending on the initial concentration, few MAP cells can survive pasteurization process. A systematic review of previous studies demonstrated that meat contaminated with MAP can be a possible source of MAP-exposure to humans. The objective of this study was to establish a reliable method to detect viable MAP cells in meat products. In the study three procedures for MAP isolation from artificially contaminated raw sausage were compared. The influence of different decontamination methods (N-Acetyl-L-Cystein-NaOH (NAC-NaOH); Hexadecylpyridiniumchlorid IHPC]) on survival of MAP as well as the effectiveness of the decontamination methods regarding the elimination of companion undesirable flora using different MAP-specific selective culture media was tested. The confirmation of MAP was carried out using an in-house developed TaqMan Real-Time PCR assay targeted to the specific MAP genome regions ISMav2 and F57. The results of six spiking experiments showed that the combination of HPC used for decontamination and Herrold's Egg Yolk Medium (HEYM) used as MAP-selective culture medium is the most sensitive method to detect MAP in raw sausages (detection limit of approximately 10 2 colony forming units (cfu)/g). In addition, the results of the study showed that the in-house developed TaqMan Real-Time PCR in combination with modified DNA extraction methods is a reliable method to detect MAP in raw sausages.
    No preview · Article · Sep 2011
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    J A Fernández-Silva · A Abdulmawjood · M Bülte
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    ABSTRACT: The objective of this study was the serological, bacteriological and molecular diagnosis, as well as the molecular characterization of Mycobacterium avium subsp. paratuberculosis (Map) in adult cows of five Colombian dairy herds. Serum samples were tested by an indirect absorbed enzyme–linked immunosorbent assay (ELISA-C). All fecal samples were tested by pooled culture. After that, fecal samples of Map positive pools were tested individually by culture and polymerase chain reaction (PCR). In one herd, slurry and tissue samples from one animal were also taken and tested by PCR and culture. Map isolates were analyzed by the Multilocus Short Sequence Repeat (MLSSR) and the Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats (MIRU-VNTR) methods. ELISA produced positive results in 1.8% (6/329) of the animals and 40% (2/5) of the herds. Four fecal, two tissue, and two slurry samples from a herd were Map positive by culture and PCR. MLSSR and MIRU-VNTR revealed two different strain profiles among eight Map isolates recovered. This study reports the first molecular characterization of Map in one dairy herd in Colombia, the limitations for individual diagnosis of subclinical Map infections in cattle, and the usefulness of pooled fecal samples and environmental sampling for Map diagnosis.
    Full-text · Article · Jun 2011 · Veterinary Medicine International
  • Jorge Arturo Fernández-Silva · Amir Abdulmawjood · Omer Akineden · Michael Bülte
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    ABSTRACT: The objective of this study is the detection of Mycobacterium avium subsp. paratuberculosis (MAP) by serum enzyme-linked immunosorbent assay (ELISA), fecal polymerase chain reaction (PCR), and fecal culture in Colombian dairy herds. Serum and fecal samples from asymptomatic cows (n = 307) of 14 dairy herds were tested for MAP by an unabsorbed ELISA test (ELISA-A). Serum and fecal samples from positive ELISA-A animals (n = 31) were further tested by an absorbed ELISA test (ELISA-B) and PCR. Fecal samples from animals of herds positive by ELISA-A and PCR (n = 105) were inoculated onto three different culture media. ELISA-A produced positive results in 10% of the serum samples and 71% of the herds. ELISA-B and PCR results were positive in two and six serum and fecal samples from positive ELISA-A animals, respectively. Fecal samples were negative for MAP on all culture media. The results of this study confirmed the presence of MAP in local dairy herds and the difficulties of MAP detection in asymptomatic animals by ELISA, PCR, and fecal culture.
    No preview · Article · Apr 2011 · Tropical Animal Health and Production