Study and characterization of selected emerging viral agents and potentially associated with hepatopathies in coastal, pelagic and mixed habitat cetaceans in Brazil

• Grant number: 19/26794-0
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2020
• End date: December 31, 2022
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Jose Luiz Catao Dias
• Grantee: Jose Luiz Catao Dias
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Cetaceans are considered "sentinel organisms" of the marine environment, as well as species of special interest on public health for sharing the coastal ecosystems with humans and feeding on similar species. Among the diseases that affect cetaceans, hepatic diseases are considered relevant and relatively common, and have also been reported in cetaceans of Brazil. In spite of that, the etiology of the majority of the hepatic lesions published to date has not been established. Different viruses have been described as etiological agents of hepatic lesions in mammals, such as herpesvirus, adenovirus and hepatitis E virus (HEV) - the latter containing certain genotypes considered zoonotic. These three agents have been previously detected in cetaceans, and hepatic damage associated with HEV infection was recently described in dolphins. Deleterious anthropogenic impacts have been described as one of the main causes of diversity loss and disease emergence. Due to exposure and susceptibility variations (animals living in more severely anthropogenically-impacted habitats could be more prone to immunosuppression), the occurrence and viral load of these infectious agents could differ among populations of coastal (<200 meters of depth), pelagic (>200 meters), and mixed habitat (coastal/pelagic), and are possibly higher in cetaceans inhabiting coastal areas. In addition, these agents could be associated with hepatic damage in cetacean species of Brazil. The present project aims on: (1) using molecular assays to compare the occurrence and the viral load of selected infectious agents (herpesvirus, adenovirus, and hepatitis E virus) in coastal, mixed and pelagic cetacean species of Brazil to indirectly evaluate the impact of human activity over their health status; (2) performing the molecular characterization of these agents using different molecular techniques, including complete sequencing, in order to establish their degree of similarity among different coastal, mixed and pelagic populations; and (3) using histopathologic, immunohistochemical and in situ hybridization techniques to establish if the selected agents are associated with hepatic lesions in cetaceans. Herein we propose a study based on conservation medicine and One Health concepts to ensure the conservation of these species and the preservation of human, animal and environmental health. (AU)