Stories tagged parasites

Jan
10
2008

Hookworms in the lining of the intestines: All together now: "ewwwwwwwwwwww."
Hookworms in the lining of the intestines: All together now: "ewwwwwwwwwwww."Courtesy Centers for Disease Control and Prevention

Cleanliness is next to godliness, but is it possible to have too much of a good thing? For several decades, immunological diseases -- such as hay fever, asthma, diabetes and multiple sclerosis – have been increasing in developed countries, but are uncommon in many undeveloped regions. Medical researcher Joel Weinstock theorizes that modern life is too clean – by scrupulously avoiding dirt, bugs and germs, our immune systems don’t develop properly, leading to the diseases listed above. Weinstock goes so far as to speculate that exposure to hookworm, pinworm, and other intestinal parasites may have been the trigger necessary for developing a healthy immune system. As these parasites have been eradicated, immunological diseases have skyrocketed.

The theory is currently being tested in the lab. Weinstock doesn’t advocate the return of worm infestations. But he does think that getting your hands dirty once in a while can help keep your body in balance.

Jan
08
2008

An alternate theory holds that dinosaurs died of embarrassment: A Fredrogersaurus, obviously wishing he were dead, extinct, or just anywhere but here.
An alternate theory holds that dinosaurs died of embarrassment: A Fredrogersaurus, obviously wishing he were dead, extinct, or just anywhere but here.Courtesy Elston

Biting insects spread all kinds of diseases. (You can learn all about this in the Science Museum’s newest exhibit, Disease Detectives.) Now a scientists thinks they may have also helped kill off the dinosaurs. George Poinar, a professor of zoology at Oregon State University, notes that many insects from dinosaur times have been preserved in amber. Many of them carry microbes that can cause malaria, dysentery and other illnesses. He speculates that these illnesses could have been the major cause of the dinosaurs’ long, slow demise. The asteroid impact / volcanic activity / climate change simply finished them off.

Poinar and his wife Roberta have published a book, What Bugged The Dinosaurs? Insects, Disease And Death In The Cretaceous. In it they also note that, late in the dinosaur era, flowering plants spread rapidly, helped along by newly-evolved insect pollinators. This sudden change in available food may have also played a hand in the dinos’ extinction.

Remember those freaky frogs first discovered by Minnesota schoolchildren in 1995? (Science Buzz did an exhibit about them, too, in early spring of 2005.) Pieter Johnson, an evolutionary biologist at the University of Colorado at Boulder (formerly of University of Wisconsin, Madison), has published his newest research: he says parasites called trematodes cause the missing and extra legs, and that runoff from farms and lawns fuels algae growth, which allows for larger snail populations, which means more trematodes and more deformed frogs....

Oct
06
2006

As I watched the praying mantis crawling on my hand, I noticed something brownish coming out of its bottom. At first I thought it was feces, but then it started wriggling around vigorously. Was it a tapeworm, or some unknown species of worm?

Praying mantis: This isn't the mantis with the hairworm. But any excuse to post a photo of a praying mantis is a good excuse to do it.
Praying mantis: This isn't the mantis with the hairworm. But any excuse to post a photo of a praying mantis is a good excuse to do it.Courtesy CatDancing

We brought the worm home in a bag and searched on the internet. It was a hairworm, a parasite that feeds on the insides of insects and brainwashes the insects into jumping into the water, where it completes its lifecycle. That makes sense because the praying mantis jumped off my hand into a wading pool just before I brought it onto land and the hairworm started coming out.
We've only found examples of hairworms coming out of grasshoppers and rarely emerging from damselfies/dragonflies. Has a hairworm ever before been observed coming out of a praying mantis? I found it on Oct. 4, 2006 at Kyodo no Mori in Fuchu-shi in Tokyo when my 4th grade class from ASIJ was on a field trip.
My name is Elsa and I am nine years old. I want to be either an entemologist or a herpetologist when I grow up.

Sep
16
2005

It seems like science fiction, or some bizarre insect zombie movie, but...


Hairworm: A hairworm swims away from its drowned grasshopper host. Image by VB Films

Scientists have been researching the parasitic relationship between grasshoppers and the nematomorph hairworm (Spinochordodes tellinii). The hairworm lives and breeds in fresh water, but spends a part of its life eating the insides of live grasshoppers and then brainwashing the grasshopper into committing suicide by hopping into a pool of water and drowning. The hairworms, several times the length of the grasshopper at the time of the unfortunate incident, then emerge and continue their lifecycle in water. A team of researchers at the French National Center for Scientific Research is studying just how the hairworm manages to take over the body of the grasshopper.

This is just one example of a parasite seemingly taking over its host to produce specific results. In Costa Rica, there is a wasp whose larva lives inside the body of an orb-weaving spider. The evening before the larva kills the spider, the larva somehow manages to reprogram the web building activity of the spider so that it creates a durable platform for the larva to pupate on, instead of its usual temporary web. Studies show that if the larva is removed from the spider before the larva kills the spider, the spider will return to its usual web building activities within a couple of days.

And, if you think about it, the rabies virus makes animals so rabid that they want to bite others — which transmits the virus.

Creepy, huh?

Jan
14
2005

In August 1995, schoolchildren found deformed frogs in a wetland near Henderson, Minnesota. Some frogs had extra legs, others no legs at all. Some had missing or extra eyes, toes, or feet. And some also had problems with their internal organs. By the fall of 1996, there were over 200 reports of freakish frogs, from two-thirds of Minnesota's counties. Deformed frogs have since been found in 44 states.

Deformed frog: This frog has two right back legs. Others have been found with missing legs, missing parts of legs, or legs in unexpected places.
Deformed frog: This frog has two right back legs. Others have been found with missing legs, missing parts of legs, or legs in unexpected places.Courtesy Minnesota Pollution Control Agency

A 1997 study raised frogs in the lab, mixing pure water with water from two Minnesota sites that had lots of deformed frogs. The more pond water that was used, the more likely the lab frogs were to be deformed. Water from sites with healthy frogs produced healthy animals in the lab. The scientific conclusion was, "There's something in the water." But what could it be? Since then, several researchers have been hunting for the cause.

Scientists have proposed several explanations for the deformities. It may be parasites, chemicals, ultraviolet light, or some combination of the three. Lab studies have shown that all of these factors, alone or in combination, can cause some deformities. But no single cause seems to explain it all. The research doesn't yet add up to a neat and tidy answer, so scientists continue to puzzle out the story.

Who cares about frogs? You should. If there's something wrong with the water, it may eventually hurt all of us. But it will hurt frogs first. Frogs have thin skins, and easily absorb any contaminants in the water. Frogs seem to be in trouble all around the world. There are more and more reports of deformities. And some species have disappeared, or no longer live in their old habitats. It's a wide-spread problem that may affect us all.