Hammerhead worms: What to do if you see these invasive pests

The peculiar-looking worms have been seen in much of the country. Here's what to know about them — and the right way to kill them

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Hammerhead flatworms — an invasive pest that looks like a cross between a hammerhead shark and a leech — have been spotted in the Washington, D.C., area and across the United States.

Experts say the worms secrete toxins that can be somewhat dangerous to humans and pets, and they're bad for the ecosystem.

Here's what you need to know about the worms, including the right way to kill them.

What is a hammerhead flatworm?

"It might kind of look like a leech to you, but it won't have the segments along it. So it's a flatworm that has a hammerhead shape. So, if you think of the hammerhead shark and a worm combined, that's exactly what this flatworm looks like. And it is a predator of earthworms and an invasive species," Ashley Morgan-Olvera, the director of research and education at the Texas Invasive Species Institute said.

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Where have hammerhead worms been spotted?

"Several hammerhead species are here and they're pretty much across the United States," Morgan-Olvera said. "They are found as far north as New York, over to California, throughout Texas and the southeastern United States."

A bug expert at the University of Maryland told WTOP that the worms are also in the D.C. area.

Are hammerhead worms poisonous?

"They do use a neurotoxin, which can sound really scary, but it's a neurotoxin that they use to digest the earthworms, and if mammals, such as ourselves or cats or dogs were to accidentally ingest the flatworm, it can cause some nausea," Morgan-Olvera said.

"It could possibly make your hands tingle if you touch it. I haven't known very many people to have a reaction to it, but we do discourage anyone handling it."

She said it's important to keep pets and children away from the worms if you spot them because they could cause nausea and vomiting.

What should I do if I find a hammerhead worm?

"Remove it, please. Please remove it. They are sensitive to vinegar. So if you are out gardening, if you have a spray bottle of 30% concentrate vinegar, you can spray them as you see them. So then you don't have to touch them," Morgan-Olvera said.

Experts warn not to cut the worms because they can regenerate.

"So that can just double your trouble if you're cutting them up. So we do want you to remove them in a sealed container, whether it's a bag, a jar, or spray them with vinegar so that they are being properly disposed of," she said.

Why is it important to get rid of hammerhead worms?

The worms cause harm to our environment because they eat earthworms, which are needed for gardens and agriculture.

"We don't want to just let them be and let them take over and remove our earthworms. So it is important that we take care in our area and remove them as quick as possible. Just because they're here and they're widespread doesn't mean we should give up the fight," Morgan-Olvera said.

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