Parasite spread by feral cats threatens native wildlife, strengthening calls for action

(Image: Thierry Work)
(Image: Thierry Work)

HONOLULU (HawaiiNewsNow) - While state lawmakers debate a measure to curb the explosive growth of feral cat colonies and protect Hawaii's indigenous and endangered species, USGS Wildlife Disease Specialist Thierry Work sees firsthand how a parasite spread by feral cats is killing Hawaii's native wildlife.

Toxoplasmosis spreads through a cat's feces. It can be fatal for birds and marine mammals that get it into their systems.

Last month, Work said, a sick nene on the Big Island tested positive for toxoplasmosis.

He's also found toxoplasmosis during necropsies of dead Hawaiian coots, Hawaiian ducks and booby birds.

"Feral cats in Hawaii are the absolute reason why we have toxoplasmosis, because we have no other native felines in Hawaii like panthers or bob cats or pumas," he said.

Michelle Barbieri, NOAA Wildlife veterinary medical officer, said there are eight documented deaths of monk seals from toxoplasmosis.

"There is increasing concern about the impact of toxoplasmosis on marine mammals in Hawaii, specifically because we've now noted several deaths of Hawaiian monk seals and spinner dolphins," she said.

But she warns that other infected monk seals may have died and not washed up on shore.

On land, the Hawaiian crow has been hardest hit. The state has kept them in captivity because so many have died from toxoplasmosis.

"They're starting to re-release them now," Work said. "For a long time, they were not viable in the wild because of that parasite."

Work hopes lawmakers provide a humane way to control feral cat colonies.

"There's not only the feral cats involved in this equation. There's animal welfare, the welfare of nene, water birds, alala, monk seals. Those animals need a voice as well," he said.

Toxoplasmosis can also be dangerous for pregnant women.

The disease and how it's spread by feral cats will be the focus of a seminar Saturday at the University of Hawaii law school. It starts at 9 a.m.

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