There is no single definitive test for these worms, but the tail is fairly convincing.

Out of nowhere, a woman’s right arm and leg started shaking uncontrollably. In the moments leading up to the experience, she seemed well; she had no headache, confusion, or weakness. But for about a minute, half of her body juddered.
The woman, a rice farmer in the Philippines, headed to the emergency department. There, doctors gave her a physical exam and found nothing out of the ordinary. Then they took a look at her brain. Magnetic resonance imaging revealed a bright cluster of nodules surrounded by fluid in her left frontal lobe. The doctors had an immediate guess as to what they were: worm eggs.

An MRI of the woman’s brain showing nodules.
Credit:
NEJM, 2026

In a case report published in the latest issue of the New England Journal of Medicine, doctors write that they suspected the woman had neuroschistosomiasis, an uncommon complication of an infection with a Schistosoma parasitic worm, aka a blood fluke. In the Philippines, the most common fluke is S. japonicum. It’s also found in China and part of Indonesia; despite its name, it has been eliminated from Japan.Read full article
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Source: Ars Technica