Comparative immunopathology of cetacean morbillivirus infection: histologic, immunohistochemical, and molecular studies

• Grant number: 18/01876-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): April 01, 2018
• Effective date (End): May 05, 2018
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Jose Luiz Catao Dias
• Grantee: Josué Díaz Delgado
• Supervisor: Sandro Mazzariol
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: Università degli Studi di Padova, Italy
• Associated to the scholarship: 17/02223-8 - Comparative immunopathology of cetacean morbillivirus infection: histologic, immunohistochemical, and molecular studies, BP.PD

Abstract

Cetacean morbillivirus (CeMV; genus Morbillivirus, family Paramyxoviridae) has caused multiple outbreaks of lethal disease in odontocetes and mysticetes worldwide. CeMV includes three well characterized strains: porpoise morbillivirus, dolphin morbillivirus, and pilot whale morbillivirus (northern hemisphere), and three novel strains, one of them detected in Brazil and considered the first description in South America. Studies suggest there is different species-specific susceptibility to CeMV infection, and bottlenose dolphins (Tursiops truncatus) and striped dolphins (Stenella coeruleoalba) are among the most susceptible ones, with historical fatal epizootics. CeMV may cause severe respiratory, lymphoid, and neurologic disease in susceptible species, leading to strandings and death. Four major presentations of CeMV-associated pathology (CeMV-AP) are currently recognized, which bear resemblance to Measles (MeV) and Distemper (CDV), the major morbilliviral diseases in humans and dogs, respectively. Furthermore, studies have shown cytokine imbalance in TH1 and TH2 immune responses plays a major role in disease susceptibility and progression in MeV- and CDV-infected individuals. No previous studies have evaluated the local immunopathogenetic aspects in tissues other than peripheral blood in CeMV-AP. This study will employ archival, formalin-fixed, paraffin-embedded and frozen tissues from organs with major pathogenetic significance (brain, lung, and lymph nodes) of CeMV-positive bottlenose dolphins and striped dolphins (Mediterranean Sea, Italy), and selected Brazilian species (southwestern Atlantic), as determined by RT-PCR analysis. A suit of lymphocytic, histiocytic and additional immunohistochemical markers will be used to characterize the local immune responses. Additionally, the expression of TH1 and TH2 cytokines will be evaluated via RT-qPCR/PCR. Parallel histopathologic, immunohistochemical, and molecular analysis may provide insight into immunopathogenetic mechanisms of CeMV-AP, a disease with worldwide distribution and major conservation significance.