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Updated: Jul 20, 2026

Detection of Abnormal Prion Protein by Immunohistochemistry
Published on: May 5, 2023
Diagnosis of paratuberculosis in a dairy herd native to Brazil
Paula Ristow1, Carla D Marassi, Ana Bárbara F Rodrigues
1Mycobacteria Laboratory, Institute of Microbiology, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, RJ, Brazil.
Abstract:
Paratuberculosis (PTB) in Brazil has previously only been reported in imported animals and is officially considered as an exotic disease. A dairy herd, which had no imported animals, presented clinically suspect animals and was investigated for paratuberculosis using faecal culture, histopathology, indirect ELISA and the agar gel immunodiffusion test. Infection with Mycobacterium avium subsp. paratuberculosis (Map) was confirmed by culture of faeces from five cows with clinical symptoms of PTB and in 7/24 randomly selected asymptomatic cows from the same herd. Two cows with clinical symptoms were necropsied and their tissues were positive for Map by culture and histopathology. Twelve asymptomatic, randomly selected cows were positive on ELISA. The results confirmed the presence of PTB in this dairy herd and for the first time demonstrated the disease in a herd of native-bred cattle in Brazil.
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