parasites

some-flies-go-insomniac-to-ward-off-parasites

Some flies go insomniac to ward off parasites

Those genes associated with metabolism were upregulated, meaning they showed an increase in activity. An observed loss of body fat and protein reserves was evidently a trade-off for resistance to mites. This suggests there was increased lipolysis, or the breakdown of fats, and proteolysis, the breakdown of proteins, in resistant lines of flies.

Parasite paranoia

The depletion of nutrients could make fruit flies less likely to survive even without mites feeding off them, but their tenaciousness when it comes to staying up through the night suggests that being parasitized by mites is still the greater risk. Because mite-resistant flies did not sleep, their oxygen consumption and activity also increased during the night to levels no different from those of control group flies during the day.

Keeping mites away involves moving around so the fly can buzz off if mites crawl too close. Knowing this, Benoit wanted to see what would happen if the resistant flies’ movement was restricted. It was doom. When the flies were restrained, the mite-resistant flies were as susceptible to mites as the controls. Activity alone was important for resisting mites.

Since mites are ectoparasites, or external parasites (as opposed to internal parasites like tapeworms), potential hosts like flies can benefit from hypervigilance. Sleep is typically beneficial to a host invaded by an internal parasite because it increases the immune response. Unfortunately for the flies, sleeping would only make them an easy meal for mites. Keeping both stereoscopic eyes out for an external parasite means there is no time left for sleep.

“The pattern of reduced sleep likely allows the flies to be more responsive during encounters with mites during the night,” the researchers said in their study, which was recently published in Biological Timing and Sleep. “There could be differences in sleep occurring during the day, but these differences may be less important as D. melanogaster sleeps much less during the day.”

Fruit flies aren’t the only creatures with sleep patterns that parasites disrupt. Evidence of shifts in sleep and rest in birds and bats has been shown to happen when there is a risk of parasitism after dark. For the flies, exhaustion has the upside of better fertility if they manage to avoid bites, so a mate must be worth all those sleepless nights.

Biological Timing and Sleep, 2025.  DOI: 10.1038/s44323-025-00031-7

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tapeworm-in-fox-poop-that-will-slowly-destroy-your-organs-is-on-the-rise

Tapeworm in fox poop that will slowly destroy your organs is on the rise

No matter how bad things might seem, at least you haven’t accidentally eaten fox poop and developed an insidious tapeworm infection that masquerades as a cancerous liver tumor while it slowly destroys your organs and eventually kills you—or, you probably haven’t done that.

What’s more, according to a newly published study in Emerging Infectious Diseases, even if you have somehow feasted on fox feces and acquired this nightmare parasite, it’s looking less likely that doctors will need to hack out chunks of your organs to try to stop it.

That’s the good news from the new study. The bad news is that, while this infection is fairly rare, it appears to be increasing. And, if you do get it, you might have a shorter lifespan than the uninfected and may be sicker in general.

Meet the fox tapeworm

The new study is a retrospective one, in which a group of doctors in Switzerland examined medical records of 334 patients who developed the disease alveolar echinococcosis (AE) over a 50-year span (1973–2022). AE is an understudied, life-threatening infection caused by the fox tapeworm, Echinococcus multilocularis. The parasite is not common, but can be found throughout the Northern Hemisphere, particularly regions of China and Russia, and countries in continental Europe and North America.

In the parasite’s intended lifecycle, adult intestinal worms release eggs into the feces of their primary host—foxes, or sometimes coyotes, dogs, or other canids. The eggs then get ingested by an intermediate host, such as voles. There, eggs develop into a spherical embryo with six hooks that pierce through the intestinal wall to migrate to the animal’s organs, primarily the liver. Once nestled into an organ, the parasites develop into multi-chambered, thin-walled cysts—a proliferative life stage that lasts indefinitely. As more cysts develop, the mass looks and acts like cancer, forming necrotic cavities and sometimes metastasizing to other organs, such as the lungs and brain. The parasite remains in these cancerous-like masses, waiting for a fox to eat the cyst-riddled organs of its host. Back in a fox, the worms attach to the intestines and grow into adults.

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burning-in-woman’s-legs-turned-out-to-be-slug-parasites-migrating-to-her-brain

Burning in woman’s legs turned out to be slug parasites migrating to her brain

It started with a bizarre burning sensation in her feet. Over the next two days, the searing pain crept up her legs. Any light touch made it worse, and over-the-counter pain medicine offered no relief.

On the third day, the 30-year-old, otherwise healthy woman from New England went to an emergency department. Her exam was normal. Her blood tests and kidney function were normal. The only thing that stood out was a high number of eosinophils—white blood cells that become active with certain allergic diseases, parasitic infections, or other medical conditions, such as cancer. The woman was discharged and advised to follow up with her primary care doctor.

Over the next few days, the scorching sensation kept advancing, invading her trunk and arms. She developed a headache that was also unfazed by over-the-counter pain medicine. Seven days into the illness, she went to a second emergency department. There, the findings were much the same: Normal exam, normal blood tests, normal kidney function, and high eosinophil count—this time higher. The reference range for this count was 0 to 400; her count was 1,050. She was given intravenous medicine to treat her severe headache, then once again discharged with a plan to see her primary care provider.

At home again, with little relief, a family member gave her a prescription sleep aid to help her get some rest. The next day, she awoke confused, saying she needed to pack for a vacation and couldn’t be reasoned with to return to bed. After hours in this fog, her partner brought her to an emergency department for a third time, this time the one at Massachusetts General Hospital.

Getting warmer

In a case report published in the New England Journal of Medicine, doctors explain how they figured out the source of her fiery symptoms—worms burrowing into her brain. By this point, she was alert but disoriented and restless. She couldn’t answer questions consistently or follow commands.

The doctors at Mass General, including a neurologist specializing in infectious diseases, quickly focused their attention on the fact that the woman had recently traveled. Just four days before her feet began burning, she had returned from a three-week trip that included stops in Bangkok, Thailand; Tokyo, Japan; and Hawaii. They asked what she ate. In Thailand, she ate street foods but nothing raw. In Japan, she ate sushi several times and spent most of her time in a hotel. In Hawaii, she again ate sushi as well as salads.

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