Macro and microscopic study of avian tuberculosis at Savannah´s Bogotá zoo

Abstract

Avian tuberculosis diagnosis was made in captive wild birds (Burhinus bistriatus and Porphyrula martinica) from a zoo park at Sabana de Bogotá (Colombia). Based on this diagnosis, a surveillance approach was designed in order to demonstrate whether or not a focus of tuberculosis infection caused by Micobacterium avium was present at this zoo with the purpose to identify a possible hazard to prevent the infection of other bird population, visitors and workers of the park. Clinical, morphological (gross and microscopic) are described in this article, but microbiological (culture in specific media), epidemiological (DPP) and molecular (PCR) studies, will be shown in other journal. In this work animals were organized en three different groups as follow: Five Hy line Brown chicken tuberculosis free coming from a commercial farm (sentinel group). A mixed group birds (102 animals) from the pens around the primary focus (28 dukes, 25 “guacamayas”, 26 parrots and 23 rapacious birds), (highest risk group). Five birds within the pen in which the diagnosis was made (contaminated birds group). It was demonstrated granulomatous lesions in animals from the sentinel group as well as in those from the pen in which the first diagnosis was made. Lesions were founded in liver, spleen, lungs, kidneys, intestines and in one case in the white matter and leptomeniges of the spinal cord were affected. Ziehl – Neelsen positive rods were identified in all the affected tissues. No tuberculosis lesions were found in animals caged in neighborhood pens. It was concluded that there is an infectious focus of tuberculosis (micobacteriosis) caused by M. avium in the zoo, but the focus is located only in one pen and this focus could represent a critical risk of infection with M. avium for some of the birds within the zoo, wild and eventually commercials birds and the human beings as well. It is recommended that prevention, control and eradication measurements have to be made to prevent the spread of tuberculosis at the zoo.