Morbillivirus and pilot whale deaths, Mediterranean Sea

Area of Science:

• Marine Mammal Health
• Virology
• Ecology

Background:

• Morbillivirus infections pose a significant threat to marine mammal populations worldwide.
• Long-finned pilot whales (Globicephala melas) are susceptible to viral pathogens, impacting their survival and population dynamics.
• Previous morbillivirus outbreaks in cetaceans highlight the need for rapid identification and characterization of novel strains.

Purpose of the Study:

• To investigate a lethal morbillivirus outbreak affecting long-finned pilot whales in the Mediterranean Sea.
• To genetically characterize the morbillivirus responsible for the pilot whale deaths.
• To determine the phylogenetic relationship of the outbreak virus to other known morbilliviruses.

Main Methods:

• Necropsy and sample collection from deceased long-finned pilot whales.
• Molecular analysis, including PCR amplification and sequencing of a conserved morbillivirus phosphoprotein gene fragment (426 bp).
• Phylogenetic analysis to compare the outbreak virus with reference morbillivirus sequences.

Main Results:

• A morbillivirus outbreak caused significant mortality in long-finned pilot whales between October 2006 and April 2007.
• Sequence analysis of the phosphoprotein gene fragment identified the causative agent as a morbillivirus.
• Phylogenetic analysis indicated the virus is more closely related to dolphin morbillivirus (DMV) than to other known pilot whale morbilliviruses.

Conclusions:

• The identified morbillivirus outbreak represents a significant epizootic event in Mediterranean long-finned pilot whales.
• The genetic findings suggest potential cross-species transmission or a shared ancestry with dolphin morbilliviruses.
• Further research is warranted to understand the epidemiology and host range of this specific morbillivirus strain.