By IDSE News Staff
Scientists at the University of Hawai'i (UH) at Manoa’s Health and Stranding Lab voiced concern after three striped dolphins were stranded on east O'ahu shorelines over seven days and tested positive for Brucella ceti, a zoonotic bacterial infection.
They worry the three cases could signal a much larger problem for dolphins and whales in Hawaiian waters.
Two of the dolphins were found in Waimanalo on June 7 and 8, and the third was found in Waikane on June 15. Cultural practitioners were present at each response and advised the UH first response team.
In humans, the infection can cause flu-like symptoms, neurologic issues and chronic arthritis if untreated.
“Brucella ceti can be dangerous to humans who touch infected marine mammals,” said Kristi West, an associate researcher at UH Manoa’s College of Tropical Agriculture and Human Resilience (CTAHR) who directs the university’s Health and Stranding Lab. “It is best to be cautious and avoid touching or handling stranded animals. We strongly urge the public to report any whales and dolphins in distress in the ocean or stranded on beaches,” she added.
Since most carcasses are never recovered, public reporting is critical for understanding threats to marine mammal health, the scientists said.
“Dolphins and whales are recognized sentinels of ocean health and give us signs and signals about what’s happening out there,” Ms. West said. “Three strandings within one week likely represents many more dolphins that died and were lost at sea. It raises our concern about what’s happening to the animals in their ecosystem.”
New Bacteria Strain
CTAHR researchers identified striped dolphins as especially vulnerable to B. ceti and discovered the bacteria in other species of stranded dolphins and whales (J Wildl Dis 2025;61[2]:522-529). Between 2000 and 2024, they found the bacteria in seven species, including pygmy killer whales, sperm whales, spinner dolphins and a Longman’s beaked whale. Many of the animals that tested positive showed severe brain and lung infections, with coinfections by viruses such as morbillivirus and herpesvirus.
Working alongside UH Manoa School of Life Sciences microbiologist Michael Norris, the team has discovered a new strain of B. ceti in Hawaiian marine mammals that is likely the cause of the recent strandings. Work is ongoing and UH will continue its investigations this summer.
This research was made possible through a Zoonotic Disease Initiative grant from the Fish and Wildlife Service to the Hawai'i Department of Land and Natural Resources.
