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Year 2013 - Volume 33, Number 12
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Imuno-histopatologic diagnosis of subclinic bovine paratuberculosis in the state of Rio de Janeiro, 33(12):1427-1432
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ABSTRACT.- Yamasaki E.M., Brito M.F., McIntosh D., Galvão A., Peixoto T.C. & Tokarnia C.H. 2013. [Imuno-histopatologic diagnosis of subclinic bovine paratuberculosis in the state of Rio de Janeiro.] Diagnóstico imuno-histopatológico da paratuberculose subclínica em bovinos no estado do Rio de Janeiro. Pesquisa Veterinária Brasileira 33(12):1427-1432. Curso de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: elise_my@yahoo.com.br
The early and specific diagnosis of paratuberculosis remains a challenge due to the low sensitivity of the currently available laboratory tests and also because of variations in the immune response towards infection with Mycobacterium avium subsp. paratuberculosis. Globally this disease causes significant economic losses, primarily in dairy cattle, owing to the chronic nature of the infection. Paratuberculosis has been described in a number of Brazilian states and from a diversity of domestic ruminant species clearly demonstrating that the disease is present in the country and highlighting the requirement for the development of diagnostic techniques for confirmation of infection and for epidemiological analyses. The aim of this study was to characterize the anatomo-histopathological and immunohistochemical findings in the bowel and mesenteric lymph nodes of assymptomatic cattle, derived from paratuberculosis positive herds located in state of Rio de Janeiro, Brazil. Macroscopic examination during necropsy revealed nonspecific changes including reddening of the gut mucosa, increased volumes for the Peyer’s patches and mesenteric lymph nodes and in some case dilation and whitening of the mesenteric lymphatic vessel. Histopathology revealed granulomatous infiltration, occasionally with the formation of giant cells in the jejunal and ileal mucosa or sub-mucosa, and/or in the cortical region of the mesenteric lymph nodes, in 32 of the 52 cattle examined. Tissue sections from these animals were subjected to Ziehl-Neelsen staining, but the presence of acid-fast bacilli was not observed. Subsequent analysis, employing genus specific immunohistochemisty for Mycobacterium, revealed areas of immunoreactivity in sections prepared from a total of six animals. The results of this investigation highlighted the value of histopathology and particularly immunohistochemistry as tools for the diagnosis of subclinical paratuberculosis. |
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