Genomic and structural investigation on dolphin morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus)

Abstract

Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990–‘92 and the 2006–‘08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells.

Circulation of a novel strain of dolphin morbillivirus (DMV) in stranded cetaceans in the Mediterranean Sea

“…Future studies on longer sequences or complete CeMV genomes are anticipated to further resolve how DMV strains evolve and circulate. Additional studies should also address the question of whether the non-synonymous substitutions observed in the P gene among different strains (Table 3) are biologically relevant, which falls in line with previously made proposals in a former Italian study 26 . In addition to P and N gene sequence analyses, further contributions could be made by including in the sequence analysis the viral haemagglutinin (H) gene, which has been shown to be highly variable among CDV strains 44,45 , particularly since the sequence variations in this gene may have consequences on host range, virulence and neutralising epitopes 46 .…”

“…Partial sequences of the nucleoprotein (N) and P genes of DMV proved identical in these seven animals and were closest to those of recent Spanish Mediterranean isolates. A comparison of these sequences with those of other reported CeMV strains (including a DMV isolated from a fin whale stranded in 2013 on the Italian coast 22 that was sequenced 26 ) was made to better understand the genetic relationships and molecular epidemiology of DMV in the Mediterranean Sea.…”

Evolutionary evidence for multi-host transmission of cetacean morbillivirus

“…Tissues from CeMV-infected cetaceans analyzed in this study were previously investigated for the presence of morbilliviruses. The samples PMV-2990/brain 7 , DMV-16A/lung 28 , DMV-muc/lung 28 , DMV-DE/2007/brain 48 , DMV-156/lung, DMV-LA/NL/11.2/lung 24 , DMV-Bph/brain 14 , 49 , and DMV-DK/2016/lung 16 were collected from animals stranded in European waters (North Sea and Mediterranean Sea). Other samples included PMV-Ulster/88 2 and PMV-53 7 _passage 4 (P4), from which no original material could be acquired.…”

Cetacean Morbillivirus and Toxoplasma gondii Co-infection in Mediterranean Monk Seal Pup, Italy

“…The large number of EVD survivors enabled detailed studies, such as the Partnership for Research on Ebola Virus (PREVAIL) III study (3), which aimed at characterizing potential EVD sequelae and EBOV persistence in a cohort of 1,144 EVD survivors in Liberia over the course of 5 years. An unexpected observation of these studies was the persistence of EBOV RNA and sometimes-replicating EBOV in the brain, eyes, and semen of survivors (4).…”

“…An unexpected observation of these studies was the persistence of EBOV RNA and sometimes-replicating EBOV in the brain, eyes, and semen of survivors (4). EBOV RNA persistence in semen of EVD survivors, measurable up to 40 months (3,5), has been associated with rare events of sexual EBOV transmission and EVD outbreak flareups (6).…”