ESAV - DZERV - Documentos de congressos (comunicações, posters, actas)
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Browsing ESAV - DZERV - Documentos de congressos (comunicações, posters, actas) by Author "Afonso, A."
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- Preventive measures in small ruminant farms suspected of paratuberculosisPublication . Esteves F, Seixas C, Amado A; Vala, Helena; Santos, C.; Cruz, R.; Albuquerque, T.; Afonso, A.; Botelho, A.; Seixas, C.; Amado, A.Paratuberculosis or Johne's disease caused by Mycobacterium avium subspecies paratuberculosis chronic disease, incurable, difficult to diagnose in ruminants. Economic losses, direct and indirect, associated with it and possible links to Crohn's disease in humans, justifying more and more exhaustive study of this disease, and the establishment of preventive measures. An epidemiological survey was conducted on 13 sheep farms or effectives in the region of Serra da Estrela, in Portugal, with clinical suspicion of paratuberculosis, with the objective to to identified flock’s carriers of disease cases and, subsequently, characterize and identify the main risk factors and implement prophylactic measures, as part of an eradication plane that allows it’s control. Therefore, in this work were tested several diagnosis’ methods, that included serological methods, histopatological diagnosis’ methods, immunohistochemical`s methods, direct PCR and bacteriological culture. The results were presented in details and revealed positive animals in the different diagnostic techniques. The serological methods revealed, by Enzime Linked Immunosorbent Assay (ELISA), 235 positive samples (9.1%) 45 doubtful (1.7%), in 2589 samples and by Agar Gel Immunodiffusion (AGID) 30 positive samples. In histopathological exam, considering the presence of at least one of the microscopic lesions characteristic of the disease, we classified 26 (60,5%) animals as compatible with Paratuberculosis. In Ziehl-Neelsen method was observed alcohol-acid-resistant bacteria in 20 animals (46,5%). In immunohistochemical method, also 20 animals (46,5%) revealed the presence of MAP. The PCR analysis of samples collected at necropsies, revealed 35 positive animals (81,4%). So, all the diagnostic tests applied, showed lower sensitivity than the PCR technique of tissues. The authors concluded that the incidence of the disease in this Portuguese region was high and regarding the preventive measures and given the specific characteristics of the farms of this particular region the authors proposed: the conduct of surveys to identify animals carrying the disease, attention to verify the origin of the animals to acquire surveillance of symptoms shown by animals, isolation of lambs, the use of previously pasteurized colostrums, prevent the use of manure on fertilization of pastures.
- Sheep paratuberculosis study in Portugal, Serra da Estrela region (preliminary results)Publication . Seixas, C.; Esteves, F.; Albuquerque, T.; Afonso, A.; Botelho, A.; Santos, C.; Vala, Helena; Amado, A.The aim of the project, started in September 2004 and with the duration of three years, is the study of Paratuberculosis incidence in sheep herds in one of the best Portuguese cheese production region. Every year producers suffer great economic losses due to the lack of control of the disease in their herds. Thirteen sheep herds were selected based in clinical signs of paratuberculosis disease. A serological survey by Elisa test, performed in 1220 animals, revealed that 5.6% were positive. Fourteen positive (9.7%) AGID tests, performed so far in 145 animals, were obtained. Post-mortem examination of these 14 animals revealed typical macroscopic lesions of paratuberculosis in all of them. Histophathological analysis showed suspected paratuberculosis microscopic lesions in seven animals. Bowel tissues with lesions, from the same 14 animals, were cultured in selective media for bacteriological analysis and also for direct detection with the ADIAVET kit. Seven tissue samples processed until now allowed the isolation of six strains, identified as Mycobacterium avium subsp. paratuberculosis by bacteriologic conventional methods. To start the molecular epidemiological study of paratuberculosis these six strains, and others isolated in the future, will be typed by molecular methods using IS900 restriction fragment length polymorphism (RFLP) analysis. This molecular approach will allow the detection of sources and routes of infection, essential for disease control. After these preliminary results, we intend to develop methods to rapidly detect Mycobacterium avium subsp. paratuberculosis in milk samples from infected and non infected sheep. With all the field and laboratory information and results gathered, it is our perspective, in three years from now, to have controlled paratuberculosis in sheep herds from Serra da Estrela region, and also to have a safe guaranty for the consumer of Serra da Estrela cheese.