"The patient tested negative for HIV, tuberculosis, lime disease, syphilis, coccidioides, histoplasma and cryptococcus." After four years of MRIs, a person's mysterious headaches, seizures and altered sense of smell and memory are diagnosed as a tapeworm growing throughout his brain.
Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome. Naturalists first became aware of our invisible lodgers in the 1600s, but it wasn’t until the past few years that we’ve become really familiar with them. This recent research has given the microbiome a cuddly kind of fame. We’ve come to appreciate how beneficial our microbes are — breaking down our food, fighting off infections and nurturing our immune system. It’s a lovely, invisible garden we should be tending for our own well-being. But in the journal Bioessays, a team of scientists has raised a creepier possibility. Perhaps our menagerie of germs is also influencing our behavior in order to advance its own evolutionary success — giving us cravings for certain foods, for example.[more inside]
CreatureCast - Rhizocephala - a charmingly animated look at the lifecycle of rhizocephalan barnacles, one of the more horrifying (non-charming) parasitic crustaceans (likewise). NOT a practitioner of parasitic castration but still disturbing: The bobbit worm. Happy swimming!
Consumption of lungworm snails can transmit the lungworm parasite Angiostrongylus cantonensis, which can cause meningitis in humans and respiratory problems in dogs, which can eat afflicted slugs while running through open fields. Researchers at the University of Exeter hooked up LEDs to these snails to study their nighttime movements through gardens and how those movements might help them act as a vector for the parasites.
The Guinea Worm, which causes Guinea Worm disease (or Dracunculiasis) is on track to be the first parasitic disease eliminated. And with only a water filter. [more inside]
Deciphering the Tools of Nature’s Zombies: The ability of parasites to alter the behaviour of their hosts fascinates both scientists and non-scientists alike. One reason that this topic resonates with so many is that it touches on core philosophical issues such as the existence of free will. If the mind is merely a machine, then it can be controlled by any entity that understands the code and has access to the machinery. This special issue of The Journal of Experimental Biology highlights some of the best-understood examples of parasite-induced changes in host brain and behaviour, encompassing both invertebrate and vertebrate hosts and micro- and macro-parasites. Full issue annotated inside: [more inside]
As if ticks weren't awful/awesome enough already, the Lone Star Tick (Amblyomma americanum) has been shown to transmit an allergy to meat in humans. [more inside]
One of the many problems farmers of various kinds of legumes need to deal with is the pea aphid. They reproduce incredibly fast and live by sucking the sap out of the plants, an electron micrograph of one in action. However, while they are terrifying parasites of legumes, they have their own yet more horrific parasites, a parasitoid wasp. Here is a really nice close up picture of one doing its thing, a video of the act, and here is a brain meltingly horrific video of a dissection of the mummified aftermath 8 days later. Essentially, these wasps deposit their eggs in a pea aphid and the growing larva feeds on it, developing there for about a week, and then consuming the host from the inside out like a Xenomorph. When it’s done, the wasp larva dries the aphid’s cuticle into a papery brittle shell and an adult wasp emerges from the aphid mummy. Legume farmers love them, and you can even order their mummies online these days. However, farmers noticed that the wasps didn't work as effectively on all of the aphids, and so researchers went to work figuring out why. It turns out that all aphids have a primary bacterial endosymbiont living inside their cells, in addition to and just like a mitochondria, and that many have some combination of five other secondary endosymbionts. Interestingly, two of those other five, Hamiltonella defensa and Serratia symbiotica have been shown to confer varying levels of resistance to the parasitoid wasp, allowing the aphid to survive infection. However, it turns out that there is yet one more layer to this story, [more inside]
"Why do parasites harm their hosts? Conventional wisdom holds that because parasites depend on their hosts for survival and transmission, they should evolve to become benign, yet many parasites cause harm. Theory predicts that parasites could evolve virulence (i.e., parasite-induced reductions in host fitness) by balancing the transmission benefits of parasite replication with the costs of host death. This idea has led researchers to predict how human interventions—such as vaccines—may alter virulence evolution, yet empirical support is critically lacking." Two papers demonstrate empirical evidence for related models predicting the origin of virulence: [more inside]
Icky face-pooping flesh mites are only the tip of the iceberg. You've heard that your gut bacteria are necessary to help you digest, meaning not all germs are bad. Without them, we couldn't digest healthily. But stop and look at how far our interconnectedness with other forms of life goes: 1. Human DNA itself is at least 8.3% ancient viruses; without one of these viruses you could never have been born. 2. Mitochondria in human cells originated when the same type of bacteria that causes typhus disease raided one of our cellular ancestors and instead of hijacking it was pressed into service. (The same origin as chloroplasts in plants from cyanobacteria). 3. Far more of the cells in your body are non-human microorganisms than actual human cells. This relationship is not just interconnectedness. This is integration. [more inside]
Myxozoa are microscopic parasites that infect fish, amphibians, and now, birds and at least one terrestrial mammal. For over a hundred years they were classified at protozoa. More recent research reveals that classification to be wide of the mark: They’re jellyfish. [more inside]
Screwworms, once the scourge of livestock (as well as pets and occasionally humans [link to VERY GRAPHIC slideshow]) throughout the Western Hemisphere, have been eradicated from the United States since 1966. In addition to constant vigilance by veterinary services and livestock handlers, who treated wounds immediately and set traps [link to 1920s informational film], the method which ultimately led to control of this horrifying pest is sterile insect technique. Maps showing the progress of the technique can be seen here. The USDA's National Agriculture Library maintains a special collection on the Screwworm Eradication Program. Here is a good overview of the problem and the USDA's solution, complete with (somewhat gruesome) pictures and videos. [more inside]
Parasites may affect brain function: Toxoplasmosis is a famous example. Now researchers have proposed that country-by-country differences in IQ can be explained, in part, by parasite burden.
Galls or plant galls are abnormal outgrowths of plant tissues. Some are hideous and some strangely beautiful, and some can even be mistaken for an actual crop of the tree. Galls often form due to insects or fungi, but the plant is an unwilling and helpless partner.
Ms. Serrao wanted to remove the wriggling, chewing larva as soon as possible, but she also realized that the botfly in her head presented a unique opportunity for a nature photographer. As a result, she videotaped herself and the efforts by her surprisingly stoic husband, Greg Hiemenz, to remove the worm-like creature. A Vacation Bug That Keeps Biting. With, of course, video.
Tongue-eating parasite found (with freak-you-out pic) off Jersey coast. Sweet dreams mefites.
Continuing the recent theme of horrifying parasites, here's an infectious little nematode that makes its host swell up into a plump, juicy, red berry so that birds will mistakenly eat its bloated ichorous abdomen and spread the eggs. (via) [more inside]
Devil facial tumor disease has ravaged the population of Tasmanian Devils in the last decade. DFTD is a transmissible cancer, i.e. the tumor cells themselves (which differ genetically from their host animal) are the agent responsible. The disease is spread by biting and other contact, and the resulting grotesque tumors interfere with feeding and lead to starvation. Poor immune response may be partially responsible. This is actually not the only such disease: canine transmissible venereal tumor is an analogue that has been known to be contagious since the 19th century. (CTVT, however, gets a proper immune response.) [more inside]
The fascinating world of the tapeworm. Everyone has heard of these parasites, but what do you really know? Not much, if you get your medical information from House. They are a menace to pets as well as humans, but they may have some hidden benefits. They have even been discussed on MeFI before! Is there anything they can't do?
Man pulls botfly larva from his own stomach. Previously, from head. From eye (Snopes, w/pictures). Wikipedia.
The origins and evolution of human intelligence: parasitic insects? viruses? mushrooms? neural darwinism? foraging? machiavellian competition? emergence? or something else?
Pram bugs invade Shetland. It's a strange wee sea beastie called a phronima. which cruises the oceans in its clear jelly barrel made from an unlucky sea squirt. More at the bottom of these Shetland nature notes here
A worm that builds a home inside the human body, lives there happily until breeding time, then begins a journey to emerge from the skin and find a body of water to lay its eggs in. Although this may very well be a pleasant journey for the worm, for the human, it's an excrutiating one. And so we begin The Tale of the Guinea Worm.
My very own parasite "I swear it had two beady eyes on it. And it came out two or three inches, looked around and then retracted. I thought it was a dream, a vision of some sort." The yuck factor of our 'little friends' vs. the yuck factor of Flushing PCB's into your nursing infant through breast feeding ("Study finds a cocktail of potentially harmful man-made chemicals in every person tested in UK...") On our day of public gnawing on bird chunks, I ask : which of the above is yuckier? And does anyone out there have a juicy parasite tale to share?
They're ugly. I mean small and really ugly! And they don't do us any favors at all. We can hold each other's hands, and share support. Our fight against them may lead to knowledge in other battles, but I think its time to go on the offensive. Its time to defang the beastie. (Maybe I should have posted this at Warfilter instead?)
Doing science by stealth Scientists have found a way of subverting the error checking mechanisms of web servers to allow them to perform calculations without the owners permission. This "Parasitic computing" could potentially use the internet as a single giant distributed computer.
Malaria is one of the planet's deadliest diseases and one of the leading causes of sickness and death in the developing world. According to the World Health Organization there are 300 to 500 million clinical cases of malaria each year resulting in 1.5 to 2.7 million deaths. Malaria is a public health problem today in more than 90 countries, inhabited by a total of some 2 400 million people -- 40% of the world's population. It is also notoriously difficult to combat because of the parasite's ability to easily evade the body's immune system. Nature Update has an article on the possibilities of designing a malarial vaccine which stimulates the immune response and has the potential of protecting people from all strains of the disease.