Morbillivirus Outbreak: Novel Measles-Like Disease Infects Dolphins, Whales Possibly Spreading in Hawaiian Waters

A novel strain of morbillivirus was recorded in 2018 as experts were attempting to identify the cause of Fraser's dolphin death in Maui, Hawaii. Morbillivirus is a type of infectious disease that is behind the death of numerous marine mammals, such as dolphins and whales, around the globe.

To identify how the virus caused a deadly outbreak, researchers at The University of Hawaiʻi at Mānoa Health and Stranding Lab studied the morbillivirus through animal autopsy, also known as necropsy.

What Is Morbillivirus?

UH Mānoa's Hawaiʻi Institute of Marine Biology expert, Health and Stranding Lab director, and co-author of the study Kristi West said that the investigation of Fraser's dolphin back in 2018 confirmed the novel virus strain of morbillivirus. West said that they were not aware of the presence of the virus until the case of Fraser's dolphin.

Morbillivirus, according to a report by KITV, is an infectious type of disease that was the culprit that caused massive deaths of marine mammals, such as whales and dolphins globally. In addition, the strain is correlated to human diseases such as measles and smallpox.

Immunohistochemistry, electron microscopy, and virus strain culturing were the selected methods to identify the infectious disease and to understand more about its role in Fraser's dolphin pathology. Among the challenges of the study is that UH Health and Stranding Lab were able to recover a minimal amount of specimens from dead dolphins and whales in the Hawaiian waters. Five percent of the recovered mammalian samples is not enough to predict the viral activity of the morbillivirus.

Novel Morbillivirus Strain vs. Marine Mammals

Fraser's dolphins are one of the most overlooked marine mammal species, as they are pelagic throughout any of the wide water bodies on our planet. Unfortunately, the humble marine mammals may decrease their population in the Hawaiian waters if the strain continue to infect them. Fraser's dolphin, according to the study, is highly vulnerable to the deadly morbillivirus.

West said in a report by the University of Hawai'i News that the presence of the morbillivirus in the country's oceans brings great concern to many marine mammal species that inhabit the region. Hawaii has a stunning collection of oceanic mammals, with over 20 species recorded.

West said that along with Fraser's dolphin, these mammals are also under the threat of the outbreak. The expert said that if the morbillivirus continues to infect, it will heavily impact the population of the Hawaiian marine mammals, starting with the country's 167 remaining false killer whales. The morbillivirus is not only a disruption to population recovery, but also a key to the extinction of marine mammals as well.

Hawaiian marine mammals, on the other hand, may have possibly developed morbillivirus immunity. Unfortunately, confirmation is yet to come, as there are still challenges in conducting antibody testing. Nevertheless, experts will still pursue possible solutions and understanding whether the morbillivirus has affected the Central Pacific species. The study of the morbillivirus outbreak in marine mammals was published in the journal Scientific Report titled "Novel Cetacean Morbillivirus in a Rare Fraser's Dolphin (Lagenodelphis hosei) Stranding from Maui, Hawai'i."

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