Archive for the ‘parasites’ Category

Cattle eyeball worms found in second human, raising worry of wriggly uprising

November 6th, 2019
Cattle eyeball worms found in second human, raising worry of wriggly uprising

Enlarge (credit: Getty | Nurphoto)

A 68-year-old Nebraska woman has become the second human in history to discover parasitic cattle worms wriggling around her eyeballs.

The cringy case—which surfaced just two years after the first case in Oregon—raises concern that the worms may be angling for an uprising in the United States.

In a recent report in the journal Clinical Infectious Diseases, parasitologists at the Centers for Disease Control and Prevention noted that the worm—Thelazia gulosa, aka the cattle eye worm—has been in the US since the 1940s. "The reasons for this species only now infecting humans remain obscure," they write. But, "[t]hat a second human infection with T. gulosa has occurred within two years of the first suggest that this may represent an emerging zoonotic disease in the United States."

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Posted in eye, Infectious disease, medical case reports, parasites, parasitic worms, science, vector-borne diseases, Worms | Comments (0)

16,000-year-old puma poop yields a sample of Ice Age parasites

August 28th, 2019
Despite their size, pumas aren't technically "big cats," a title reserved for the family Pantherinae.

Enlarge / Despite their size, pumas aren't technically "big cats," a title reserved for the family Pantherinae. (credit: By Wolves201 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=60454559)

When you’re an 80kg (180lb) apex predator with massive teeth and claws, the world is your litter box—but you might have to wait a few thousand years for someone to come along and clean it up. Archaeologists recently scooped up a dried piece of 16,500-year-old puma feces (called a coprolite) from the floor of the Peñas de las Trampas rock shelter in the mountains of northwest Argentina.

The cold, dry environment helped preserve the material, along with its cargo of a few dozen roundworm eggs, well enough for parasitologist Romina Petrigh and her colleagues to sequence DNA from the eggs. The result is the oldest DNA ever recovered from feces and the oldest parasite DNA ever sequenced.

Big cats and tiny worms

Mitochondrial DNA from the coprolite itself revealed what had left the evidence behind: a puma, the largest member of the family Felidae, which also includes domestic cats. The dried-up calling card showed that Ice Age pumas shared the southernmost reaches of South America with giant ground sloths, now-extinct American horses, and the relatives of modern alpacas and llamas. It also offers a sample of the less-charismatic part of the ecosystem: the parasites that infected the local megafauna. The combination is a snapshot of the complex, untouched world people first walked into around 15,000 years ago (as far as we know based on current evidence; the human settlement timeline is regularly revised as new sites turn up).

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Posted in ancient DNA, Archaeology, Cats, Coprolite, parasites, roundworm, science | Comments (0)

Savage tick-clone armies are sucking cows to death; experts fear for humans

July 11th, 2019
Scary arachnid is fat.

Enlarge / Engorged Haemaphysalis longicornis female tick. (credit: Commonsource)

Ravenous swarms of cloned ticks have killed a fifth cow in North Carolina by exsanguination—that is, by draining it of blood—the state’s Department of Agriculture and Consumer Services warned this week.

Experts fear that the bloodthirsty throngs, which were first noticed in the United States in 2017, will continue their rampage, siphoning life out of animals and eventually transmitting diseases, potentially deadly ones, to humans.

Just last month, infectious disease researchers in New York reported the first case of the tick species biting a human in the US. The finding was “unsurprising” given the tick’s ferocious nature, according to Dr. Bobbi S. Pritt, director of the Clinical Parasitology Laboratory in Mayo Clinic. And it’s “extremely worrisome for several reasons,” she wrote in a commentary for the journal Clinical Infectious Diseases.

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Posted in Asian longhorned tick, cattle, cow, Haemaphysalis longicornis, Infectious disease, Invasive species, parasites, public health, science, ticks, vector-borne diseases | Comments (0)

Cockroaches deliver karate kicks to avoid being turned into “zombies”

November 3rd, 2018
A wasp climbs atop a cockroach against a white background.

Enlarge / The jewel wasp administers two stings: one to paralyze the legs, the other to make the roach her zombie slave. (credit: Ken Catania/Vanderbilt University)

If you ever want to witness just how horrifyingly "red in tooth and claw" nature can be, you only have to look to the emerald jewel wasp. The female of the species is known for stinging unsuspecting cockroaches with a nasty venom that turns the roach into her docile slave. That way she can lay her eggs in the still-living roach and bury it alive, ensuring her offspring have something to eat when they hatch. Even if you don't like cockroaches, it's a pretty gruesome fate—they become the walking dead.

But it turns out that the poor roach is not without defenses of its own, according to a new paper in Brain, Behavior and Evolution with the rather puckish title, "How Not To Be Turned Into a Zombie." Roaches can use their hard, spiky legs as weapons, even delivering wide sweeping kicks to ward off an attacking jewel wasp. It's the most detailed study yet of how roaches fight off attacks to turn them into insectoid zombies.

The author, Vanderbilt University's Ken Catania, has a knack for creatively studying the aggressive behavior of various creatures; his specialty is predator/prey interactions. Back in 2016, he experimentally verified naturalist and explorer Alexander von Humboldt's 19th-century account of electric eels in Venezuela aggressively leaping up and stunning horses with a series of high-voltage discharges. (Part of that experiment involved LED lights mounted on a fake alligator head, attached with strips of conductive tape, to better visualize those discharges. Because of course it did.)

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Posted in cockroaches, jewel wasps, parasites, predator/prey, science, zombie roaches | Comments (0)