WELLINGTON, Sept. 22 (Xinhua) -- Toxoplasmosis has been confirmed as the cause of death of a pregnant Hector's dolphin found dead on a beach in southern New Zealand last month, the Department of Conservation (DOC) said Tuesday.
The female Hector's dolphin was found at Invercargill's Oreti Beach on Aug. 20. A necropsy confirmed the dolphin died from toxoplasmosis, a disease caused by the parasite Toxoplasma gondii, and was carrying a small male calf.
The loss of a pregnant female and her calf is significant for the threatened species, DOC Marine Species Manager Michelle Boyle said in a statement.
"Hector's dolphins are found only in New Zealand waters, and every individual is important to the population and its recovery," Boyle said, adding that Hector's and Maui dolphins' nearshore habitat can expose them to contaminants entering the marine environment from land.
Toxoplasmosis can infect a wide range of warm-blooded animals. Cats are the only host in which the parasite can reproduce and produce eggs known as oocysts, according to the DOC.
The microscopic eggs can survive for months or even years and enter waterways and marine environments through contaminated soil and freshwater runoff, where they can infect marine mammals, the statement said.
Research by DOC and its partners is helping scientists better understand the risk toxoplasmosis poses to Hector's and Maui dolphins, it said, warning that activities on land can also affect the health of marine species. ■