Margineda, et al.; Mycoplasma bovis pneumonia in feedlot cattle and dairy calves in Argentina. Braz J Vet Pathol, 2017, 10(2), 79 -86. DOI: 10.24070/bjvp.1983 Abstract Mycoplasma bovis has emerged as an important cause of feedlot pneumonia in many countries. The aim of this paper is to describe six cases of bovine Mycoplasma pneumonia in five different premises in Argentina. Gross examination revealed chronic bronchopneumonia with multiple foci of caseous necrosis. Microscopically, these contained a necrotic center with abundant hypereosinophilic granular material surrounded by granulation tissue. Affected lung tested positive for M. bovis by immunohistochemistry and electron microscopy revealed membranous structures compatible with Mycoplasma spp. To our knowledge, this is the first report of M. bovis pneumonia in Argentina.

The current study describes a naturally occurring cluster of cases of Wedelia glauca intoxication. Seven of 14 axis deer ( Axis axis) and 1 of 8 llamas ( Lama glama) in a zoo of Buenos Aires province, Argentina, died suddenly after ingestion of a new batch of alfalfa ( Medicago sativa) hay bales contaminated with the hepatotoxic plant W. glauca. Necropsies of 1 deer and 1 llama were performed. Pathological findings in both animals included severe diffuse acute centrilobular hepatocellular necrosis and hemorrhage, and clear yellowish translucent gelatinous edema on the wall of the gall bladder and the serosa of the choledochoduodenal junction. Fragments of W. glauca plants were identified in the hay based on the botanical characteristics of the leaves. Samples of gastric contents were examined by microhistological analysis, which identified epidermal fragments of W. glauca based on the presence of characteristic uniseriate glandular hairs (trichomes), confirming recent ingestion of W. glauca in both cases. The fragments were quantified and represented 5% of all examined vegetal fragments in the deer and 10% in the llama.