Pink blood, green blood, or no blood at all – when it comes to what's inside a worm's body, the answer is more complicated – and fascinating – than you'd think.
The predatory flatworm Obama nungara travelled in potted plants from Argentina to Europe, where it's distrupting soil ecosystems. Now, citizen-scientists are helping map their distribution.
There are three classes of parasites that can cause disease in humans. Here's what you need to know.