Systematic beach monitoring as a health assessment tool: cetacean morbillivirus under non-epizootic circumstances in stranded dolphins

Cetacean morbillivirus (CeMV) was identified as the etiologic agent of several epizootic episodes worldwide. Most of these studies are based on unusual mortality events or identification of new viral strains. We investigated the occurrence of CeMV under non-epizootic circumstances at a world heritage in Southern Brazil by a combination of pathologic, immunohistochemical and molecular assays. From 325 stranded cetaceans, 40 were included. Guiana dolphin ( Sotalia guianensis ) was the species most frequent. Interstitial pneumonia and non-suppurative encephalitis were the main pathologic findings associated to CeMV infection. Intracytoplasmic immunolabeling anti-CeMV was observed mainly in lungs and lymph nodes. All samples were negative in RT-PCR assay. Diagnosis of CeMV is challenging in areas where epizootic episodes have not been recorded and due to postmortem changes. We observed a CeMV prevalence of 27.5%. The results described here increase the knowledge about CeMV under non-epizootic conditions in Brazil. Article Summary Line We observed a prevalence of 27.5% of CeMV in a World Heritage site of Paraná’s coast. The results indicate an increase in the prevalence of CeMV at this region and, possibly, a degradation of marine ecosystem. Marine mammals are sentinels of marine environment and the ocean health is inextricably linked to human health on a global scale.