Molecular characterization of cetacean poxviruses along the coast of mainland Portugal.

Cetacean poxvirus (CePV) is the causative agent of tattoo skin disease (TSD) in dolphins, porpoises and whales, a condition characterized by pinhole, ring-like lesions or generalized tattoo-like skin lesions. This study genetically characterized cetacean poxviruses from stranded animals along mainland Portugal. Samples from skin lesions compatible with TSD were obtained from 4 odontocete species (Delphinus delphis, Stenella coeruleoalba, Phocoena phocoena, and Tursiops truncatus) and analyzed using a conventional PCR assay targeting the DNA polymerase gene partially. Among the positive samples (n = 29, 65.9%), a larger DNA polymerase gene fragment was obtained, allowing a robust phylogenetic analysis. Nineteen samples (43.2%) were successfully amplified and sequenced using Sanger sequencing. By combining 11 of these sequences with those from public databases, a maximum likelihood phylogenetic tree was constructed, revealing high heterogeneity within the group. These findings contribute to a better understanding of the genetic diversity, epidemiology, phylogenetics, and evolution of CePV.

New insight into dolphin morbillivirus phylogeny and epidemiology in the northeast Atlantic: opportunistic study in cetaceans stranded along the Portuguese and Galician coasts.

BACKGROUND: Screening Atlantic cetacean populations for Cetacean Morbillivirus (CeMV) is essential to understand the epidemiology of the disease. In Europe, Portugal and Spain have the highest cetacean stranding rates, mostly due to the vast extension of coastline. Morbillivirus infection has been associated with high morbidity and mortality in cetaceans, especially in outbreaks reported in the Mediterranean Sea. However, scarce information is available regarding this disease in cetaceans from the North-East Atlantic populations. The presence of CeMV genomic RNA was investigated by reverse transcription-quantitative PCR in samples from 279 specimens stranded along the Portuguese and Galician coastlines collected between 2004 and 2015. RESULTS: A total of sixteen animals (n = 16/279, 5.7 %) were positive. The highest prevalence of DMV was registered in striped dolphins (Stenella coeruleoalba) (n = 14/69; 20.3 %), slightly higher in those collected in Galicia (n = 8/33; 24.2 %) than in Portugal (n = 6/36; 16.7 %). CONCLUSIONS: Phylogenetic analysis revealed that, despite the low genetic distances between samples, the high posterior probability (PP) values obtained strongly support the separation of the Portuguese and Galician sequences in an independent branch, separately from samples from the Mediterranean and the Canary Islands. Furthermore, evidence suggests an endemic rather than an epidemic situation in the striped dolphin populations from Portugal and Galicia, since no outbreaks have been detected and positive samples have been detected annually since 2007, indicating that this virus is actively circulating in these populations and reaching prevalence values as high as 24 % among the Galician samples tested.