Research of Viral Agent in Free-living Pigeon Feces (Columba livia) in the City of São Paulo, SP, Brazil, for Transmission Electron Microscopy

Abstract

The pigeon feces are vehicle of diseases both for humans and other animal species. In these birds, the most important viral diseases of the digestive tract are transmitted by the paramyxovirus, adenovirus and coronavirus. Avian paramyxoviruses have been isolated from a variety of species of free living and domestic birds worldwide, with several symptoms and clinical signs and economic losses. Paramyxoviruses belong to the Paramyxoviridae family and Avulovirus genus that includes nine serotypes (APMV 1 to 9). Avian adenoviruses belong to the Adenoviridae family and Aviadenovirus genus. In pigeons, cause classical adenovirosis and necrotizing hepatitis. The respiratory and enteric tracts are common targets of coronavirus. They belong to the Coronaviridae family and to 3a and 3c groups. In this study, we described the presence of viral agents in free-living pigeon feces (Columba livia) from the city of São Paulo, Brazil. The feces were processed by negative staining technique (rapid preparation) for transmission electron microscopy. In this technique paramyxoviruses particles, pleomorphic, roughly spherical or filamentous, measuring 100 to 500 nm of diameter containing an envelope covered by spikes, with characteristic helical herring-bone-like nucleocapsid, measuring 15 to 20 nm in diameter, were visualized in 45 (79%) out of 57 feces samples. In 2 (3.5%) samples, paramyxovirus and adenovirus particles were simultaneously visualized. Adenovirus particles were isometric, spherical, characterized as “complete "or" empty ", measuring between 70 and 90 nm in diameter. Paramyxovirus and coronavirus particles were detected in 3 (5.2%) samples. Coronaviruses were pleomorphic with a diameter of 75-160 nm containing a solar corona-shaped envelope, with projections of approximately 20 nm of diameter. Seven (12.3%) samples were negative for viral particles.