After two years of investigating the death of a stranded Fraser’s dolphin in Maui, Hawaii, researchers at the University of Hawaiʻi at Mānoa have identified a yet unknown strain of the Cetacean morbillivirus (CeMV). During the last decade, CeMV has been linked to two major mortality events for both dolphins and whales.
Interestingly, the genetic sequence of the novel strain is largely distinct from the other six known CeMV strains. Based on laboratory experiments, it also does not seem to spread through airborne transmission like the other viruses but is transmitted through cell-to-cell contact instead. This high transmission risk is especially concerning regarding the high sociability of most cetacean groups, within and between species. Since the populations around Hawaii are largely unique and already at a dangerously low population size, an outbreak could be devastating.
Monitoring and even recognizing a spreading disease among cetaceans is, however, incredibly difficult. Fraser dolphins alone have only been seen six times in the Hawaiian waters during the last twenty years. Even with more common species, a carcass recovery rate of just 2% keeps the monitoring possibilities to a minimum. Researchers, therefore, hope for public support to increase reporting efforts and highlight the focus on examining single cases.
To advance understanding of the novel strain, the research group is now sequencing the full genome of the virus. Meanwhile, efforts increase to determine the strain circulating in the Central Pacific to administer effective strategies.
The study can be accessed here: West, K.L., Silva-Krott, I., Landrau-Giovannetti, N. et al. Novel cetacean morbillivirus in a rare Fraser’s dolphin (Lagenodelphis hosei) stranding from Maui, Hawai‘i. Sci Rep 11, 15986 (2021). https://doi.org/10.1038/s41598-021-94460-6.
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