Never-Before-Seen Virus Found In Hawaiian Dolphin Could Spark Mass Marine Mammal Deaths


Tom Hale

Senior Journalist

clockAug 11 2021, 11:16 UTC
Fraser’s dolphin.

Fraser's dolphins (Lagenodelphis hosei) are found in tropical waters worldwide. Image credit: Tom Meaker/

A never-before-seen strain of virus has been identified in a dolphin in Hawaii and scientists fear it has the potential to cause a wider outbreak among marine mammals.

As reported in the journal Nature Scientific Reports, scientists at the University of Hawaiʻi at Mānoa Health and Stranding Lab carried out an autopsy of a Fraser’s dolphin that washed up in Maui in 2018. The dolphin was a young male that appeared relatively healthy from first impressions, but many of its tissues showed signs of an infection. From its tissue, the researchers were able to isolate a novel morbillivirus that’s not been documented before. 


“The 2018 stranding of the Fraser’s dolphin revealed that we have a novel and very divergent strain of morbillivirus here in Hawaiian waters that we were previously unaware of,” Kristi West, lead study author and associate researcher at UH Mānoa’s Hawaiʻi Institute of Marine Biology, said in a statement.

Morbillivirus is a broad genus of viruses that cause measles in humans, distemper in dogs and cats, and rinderpest in cattle. Cetacean morbillivirus — which can not infect humans — has previously been identified before in dolphins, whales, and other marine mammals across the world and they have been known to wreak havoc on populations. In 2013, two morbillivirus strains were found in dolphins in the southern Pacific, leading to the deaths of at least 50 dolphins in Western Australia and over 200 dolphins in Brazil.

The novel cetacean morbillivirus has only been found in a single dolphin so far, but the researchers explain that they only recover less than 5 percent of cetaceans that die in Hawaiian waters, leaving the scale of the problem unclear.


The discovery of a novel morbillivirus in Fraser’s dolphins is especially concerning as they are a pelagic species that migrate between the open ocean and coastal systems. Fraser’s dolphins are also an extremely social species that closely interact with other populations of cetaceans. The risk of the virus circulating in the central Pacific and perhaps beyond is, therefore, a worrying possibility. If that becomes a reality, then it won’t just be mass mortality events on the cards, we might even see some species pushed towards extinction. 

“It’s also significant to us here in Hawaiʻi because we have many other species of dolphins and whales—about 20 species that call Hawaiʻi home—that may also be vulnerable to an outbreak from this virus,” explained West.

“An example is our insular endangered false killer whales—where there is only estimated to be 167 individuals remaining. If morbillivirus were to spread through that population, it not only poses a major hurdle to population recovery, but also could be a threat to extinction,” continued West.

 This Week in IFLScience

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