HONOLULU (KHON2) — Researchers at the University of Hawaii at Manoa have found that the cause of death for two spinner dolphins was due to the infection of a parasite that’s found in invasive species on land.

According to the researchers, one of the dolphins was found on the Big Island in 2015 and the other on Oahu in 2019.

Check out more news from around Hawaii

Both were infected with the parasite Toxoplasma gondii which is harbored by animals like pigs, mongooses, chickens and cats.

UH researchers said they screened archive tissues from past dolphin and whale strandings and only found the parasite in those animals that had died from it. This makes researchers believe that severe toxoplasmosis infection is deadly to spinner dolphins.

“We suspect that many more spinner dolphins may succumb to toxoplasmosis and die than the animals that are recovered dead and examined for cause of death,” said Kristi West, associate researcher at UH Mānoa’s Hawaii Institute of Marine Biology who directs the UH Health and Stranding Lab.

Toxoplasmosis reproduces in the digestive system of cats and the oocytes (eggs) are found in the animal’s feces.

Get news on the go with KHON 2GO, KHON’s morning podcast, every morning at 8

Researchers presume that the dolphins may have gotten the parasite from water or prey contaminated with oocytes.