# Complete Genome Sequencing of the Divergent Guiana Dolphin Morbillivirus (GDMV), Brazil

## TL;DR

This study reports the first complete genome sequence of the Guiana dolphin morbillivirus, a new strain in the CeMV-2 lineage, isolated from dolphins in Brazil.

## Contribution

The first complete genome sequence of the Guiana dolphin morbillivirus (GDMV) is presented, revealing it as a distinct morbillivirus species.

## Key findings

- The GDMV genome is 15,607 nucleotides long and covers 99.3% of the DMV reference genome.
- GDMV shares 74–77.9% sequence similarity with other CeMV strains, with highest identity to DMV.
- GDMV represents a new CeMV-2 lineage despite infecting a similar host spectrum as CeMV-1 strains.

## Abstract

Cetacean morbillivirus (CeMV) is a major threat to cetaceans worldwide, causing individual deaths and outbreaks of mass mortality. Based on partial sequences of the viral phosphoprotein, CeMV is subclassified into seven strains and two distinct lineages. To date, only CeMV-1 strains, including the dolphin morbillivirus (DMV), have been completely sequenced. The CeMV-2 lineage was first reported in Guiana dolphins (Sotalia guianensis) in Brazil and was associated with an unusual mortality event in 2017–2018. Here we provide the nearly complete Guiana dolphin morbillivirus (GDMV) genome sequence, representing the first within the CeMV-2 lineage. GDMV was isolated using Vero.DogSLAMtag cells, the viral RNA was extracted, and deep sequencing analysis was performed. Gaps in the viral genome were completed by Sanger sequencing. The final genome length was 15,607 nucleotides covering 99.3% of the DMV reference genome, including full sequences of the six structural proteins encoded by morbillivirus. The sequence similarity was 74–77.9% to other CeMV strains, with highest identity to the DMV. The complete L protein amino acid sequence comparison-based taxonomy indicates that GDMV is a distinct morbillivirus species; however, as GDMV and CeMV-1 strains infect a similar host spectrum, our findings support that GDMV represents a new CeMV-2 lineage.