The discovery of millions of fire ants in Kauai, Hawaii, marks the island's most extensive infestation since the invasive species was first detected there in 1999, the news website SFGATE reported.

The infestation poses a risk to pets, the agriculture industry, and residents and tourists visiting Hawaii's fourth-largest island, according to SFGATE.

"They're changing the way of life for our residents here in Hawaii," said Heather Forester, who works for Hawaii Ant Lab, per the news website.

"You used to be able to go out hiking and go to the beach. They can rain down on people and sting them."

Forester told SFGATE that the ants could invade people's homes in heavily infested areas. "We have a lot of reports of them stinging people while they sleep in their beds," she said.

Fire ant stings can cause red, swollen welts that burn and itch. They can also, on occasion, cause painful pus-filled lesions, according to WebMD.

Welts caused by the stings can "last for weeks", the Kauai Invasive Species Committee said, per SFGATE.

The Kauai Invasive Species Committee has launched a significant media campaign to alert residents of the free-at-home test kits available to help them detect the presence of the invasive species, SFGATE reported.

The committee hopes to contain the spread of millions of fire ants, which it says originated on private property in Kauai, Hawaii's fourth largest island. The infestation spread over a cliffside into a valley near the Wailua River, the committee's general outreach specialist Haylin Chock said, per SFGATE.

Hawaii, Maui, and Oahu also have "a varying degree of infestation", according to Forester, per SFGATE.

It's unclear if the infestation is yet to reach the water, but this would be "concerning" because it would allow the fire ants to "easily float down and create multiple colonies".

Currently, the team is hopeful that the infestation is being halted from spreading across the island.

"Our team is really good at what they do," said Chock, SFGATE reported. "I'm going to say that we're hopeful that it hasn't spread that far. I'm confident that we can keep it contained."

Defeating the fire ants involves baiting them with poisoned food which they then take back to the colony, SFGATE said.

This article was originally published by Business Insider.

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