What if little creatures hijack your brain and try to control your mind and life?

What if little creatures hijack your brain and try to control your mind and life? Science fiction? No, science fact!

Heard about these horror facts stuff? Here are some of the examples of parasites and how they control the brains of bigger organisms. Makes you ponder how the brilliant evolution of some organisms can become so dangerous for other living beings. You will also wonder why the 'prey' didn't become wise enough to evolve to beat their enemies in the game. And realize that it is the Nature's way of controlling the explosion of some animal populations!

First let us see how human beings can fall victim to these 'brain capturing' enemies...

1. The most important one that takes the top position is Toxoplasma gondii , a neurological parasite. This is very a tiny protozoan but once it makes its way to the brain, it can radically alter the behaviour of hosts like rats, cats and alarmingly even humans.

The life cycle of this organisms begins in cat faeces, where its eggs (known as “oocytes” or “egg cells”) wait to be picked up by carriers like rats. Once they’re safe and warm in the guts of their temporary hosts, the oocytes morph into tachyzoites, the unassuming little balls that can really do some damage. Those tachyzoites migrate into their hosts’ muscles, eyes and brains, where they can remain hidden for decades without doing much of anything. But when the moment comes to strike, the little T. gondii tachyzoites alter their hosts’ brain chemistry. Infected rats actually become sexually aroused by the smell of cats, and leap fearlessly into their claws, where they die and release the tachyzoites back into the cats, allowing the egg-laying cycle to start anew.

And - this can become plots of horror films - rats aren’t the only hosts in which T. gondii hibernates. Some researchers estimate that as much as 30% of the people on earth — more than two billion of us — are carrying little T. gondii tachyzoites around in our brains right now.

How can human beings get infected?
1. Contact with cats or cat feces
2. Eating raw or under-cooked meat
3. Drinking raw milk from an infected goat (Goats can be an intermediate host for the parasite.)
4. Organ transplantation or blood transfusion from an infected person
5. Eating unwashed fruits and vegetables or drinking contaminated water.

What might this mean for human behaviour? Some studies have found that cases of schizophrenia rose sharply around the turn of the twentieth century, when domestic cat ownership became common. We often see symptoms like altered activity levels, changes in risk behaviors, and decreased reaction times. Now a rage disorder has been linked to this organism as well (1).

In a survey of different countries, scientists found that people living in those with higher rates of T. gondii infection scored higher on average for neuroticism, defined as an emotional or mental disorder characterized by high levels of anxiety, insecurity or depression affecting the cultures they live in (2).

In the study of more than 350 adults, those with a psychiatric disorder called Intermittent Explosive Disorder, or IED, were twice as likely to have been infected by the toxoplasmosis parasite compared with healthy individuals with no psychiatric diagnosis. The study adds to a growing body of evidence suggesting that toxoplasmosis — usually a mild or nonsymptomatic infection from the protozoan parasite — may somehow alter people's brain chemistry to cause long-term behavior problems. Previous studies have linked toxoplasmosis to schizophrenia, bipolar disorder, impulsivity and suicidal behavior.

Infected parents, researchers found, have a 30 percent chance of passing the parasite on to their children as well.

Treatment:
Pyrimethamine (Daraprim). This medication, typically used for malaria, is a folic acid antagonist. It may prevent your body from absorbing the B vitamin folate (folic acid, vitamin B-9), especially when you take high doses over a long period. For that reason, your doctor may recommend taking additional folic acid. Other potential side effects of pyrimethamine include bone marrow suppression and liver toxicity.
Sulfadiazine. This antibiotic is used with pyrimethamine to treat toxoplasmosis.

However, recent research says these things are a little bit exaggerated. Although recent reports have suggested that infection might influence aspects of the host’s behavior. In particular,Toxoplasma infection has been linked to schizophrenia, suicide attempt, differences in aspects of personality and poorer neurocognitive performance. But, these studies are often conducted in clinical samples or convenience samples (3) and don't represent a true picture when all the parameters are taken into account. One explanation is that the researchers failure to detect statistically significant associations between T.gondii infection and brain and behavior impairments represents a false negative in an accumulating evidence base. False negative findings arise for a number of reasons, including low statistical power to detect associations due to small sample sizes.

I am giving you both the old and new research results to let the readers know and realize that in the presence of conflicting reports, better research designs are needed to fully establish the extent to which T. gondii influences impairments in brain and behavior phenotypes.

2. Village and urban ponds often play host to Naegleria fowleri, an amoeba species with an affinity for human brain tissue.

N. fowleri can spend long spans of time just hanging around as a cyst, a little armored ball that can survive cold, heat, and dry conditions. When a cyst comes into contact with a host, it sprouts tentacle-like pseudopods and turns into a form known as a trophozoite. Once it’s transformed, the trophozoite heads straight for the host’s central nervous system, following nerve fibers inward in search of the brain.

Once it’s burrowed into its host’s brain tissue — usually the olfactory bulbs — N. fowleri sprouts a sucking apparatus called an amoebostome and starts eating brain matter. As the amoeba divides, multiplies and moves inward, devouring brain cells as it goes, its hosts can go from uncomfortable to incoherent to unconscious in a matter of hours.

The symptoms start subtly, with alterations in tastes and smells, and some fever and stiffness. But over the next few days, as N. fowleri burrows deeper into the brain’s cognitive structures, victims start feeling confused, have trouble paying attention, and begin to hallucinate. Next come seizures and unconsciousness, as the brain loses all control. Two weeks later, the victim’s most likely perishes.

If you want to avoid this happening to you, stay away from warm pools of still water.

3. Rabies. Now this sounds familiar! Doesn't it? The infection that can be transferred from animals to man. This neurotropic virus (A neurotropic virus is a virus that is capable of infecting nerve cells. A neurotropic virus is said to be neuroinvasive if it is capable of accessing or entering the nervous system and neurovirulent if it is capable of causing disease within the nervous system) — so small and sneaky that it often escapes detection by the immune system. A simple puncture wound will make the virus enter a human being. Rabies transmission can occur through the saliva of animals and less commonly through contact with human saliva. Once it’s inside the host’s bloodstream, it quickly starts taking over cells, transforming them into rabies factories that produce thousands of copies of the virus. As the attackers grow in number, they make their way to the host’s central nervous system, and head for the brain.

But rabies viruses don’t just settle down anywhere in the brain, they specifically target the hippocampus, amygdala and hypothalamus, brain structures that play central roles in memory, fear and emotion. And they don’t just devour brain cells indiscriminately, either; instead, they alter the ways these cells release neurotransmitters like serotonin, GABA, and endogenous opioids. In other words, they turn their hosts’ own brain chemistry against them.

In the altered states brought on by a rabies infection, animals often lash out at any nearby living thing, but this may be more out of fear than anger. Human rabies patients become terrified of water and puffs of air, both of which make them withdraw and tremble uncontrollably.

If the infection goes untreated, rabies patients fall deeper into confusion and hallucination, lashing out at imagined threats and hapless bystanders. They lose their ability to sleep, sweat profusely, and finally fall into a paralyzed stupor as their brain function slips into chaos. A few days later, as the paralysis reaches their hearts and lungs, they fall into a coma and die. Once rabies has infected a human, survival is all-but impossible. The better news, though, is that it’s easily preventable with a vaccine at the right time.

4. The sleep parasite. In the sub-Saharan Africa and the Amazon forests, a tiniest insect can bring a sleep that leads to death. The tsetse fly likes the taste of human blood, and it often carries a parasite known as Trypanosoma, whose tastes get them addicted to human brains.

Parasites of the genus Trypanosoma start their lives in the guts of invertebrate hosts, but quickly develop through a series of increasingly complex forms when they come into contact with the mammalian fluids they crave. In the first stage of infection, known as the haemolymphatic stage, the parasites live in the host’s blood and lymph nodes, where they grow from little ovals into long squirmy blots equipped with whip-like flagellae.

As they mature, the parasites cross the blood-brain barrier and the encephalitic stage begins. The Trypanosoma alter the structure and function of their hosts’ brain cells (the parasites seem have a particular affinity for the hypothalamus, which helps regulate our mood and sleep/wake cycles) and the hosts start to feel and behave strangely. First they suffer headaches and have trouble sleeping, or sleep and wake at odd hours, due to the parasite’s alteration of the rhythm in which the sleep hormone melatonin gets released.

Then human hosts start to exhibit other psychological symptoms, from changing appetites to depression to odd speech patterns to uncontrollable itching and tremors. Over the next few years, the host’s odd behavior gradually starts to lapse into laziness, unresponsiveness, and finally a prolonged sleep that leads to coma and death, hence the name “sleeping sickness.”

Although a cure exists, it is difficult to identify symptoms, which can be mistaken for other conditions, until it is too late.

Now let us see how other animals - and in some cases human beings too - become slaves to some 'zombies'...

First watch these wonderful videos

1. Hymenoepimecis argyraphaga is a Costa Rican parasitic wasp that torments the spider Plesiometa argyra. Parasitoid wasps lay their eggs inside their victims, with the offspring eventually devouring their way out. A number of the species control their host's minds in extraordinary ways — the larvae of the wasp, which infests the spider, makes their victims spin unusual webs especially well-suited for supporting their cocoons.

When it's time to procreate, an adult female wasp will seek out a spider, paralyze it and then lay an egg on its abdomen. After hatching, the larva wasp will feed on its host, while the spider goes about its business like nothing's wrong. After a couple weeks of bloodsucking, the larva will inject a chemical into the spider, which causes the spider to build a web like none it's ever built before. The spider sits motionless in its ugly but super durable web that is able to withstand pelts of rain — to await its fate. The parasite then kills the spider with poison, sucks it dry and builds a cocoon that hangs from the middle of the new web!

2. Eye-infesting parasites: The worm Loa loa, which dwells in rainforests and swamps of West Africa, infects people through the bite of a deer fly or a mango fly. The worms wander under the skin of their victims at all times of day, feeding on fluids in human tissues. The worms live in the bloodstream when the sun is out and people are most likely to get bitten by flies that can, in turn, spread the worms to other unwitting martyrs; they retreat into the lungs at night. They occasionally cross into the eyes, where they can be quite painful.

3. Head-bursting fungus: In a bizarre death sentence, the fungus Ophiocordyceps unilateralis turns carpenter ants into the walking dead. The fungus prefers the undersides of leaves of plants growing on the forest floor. That's where temperature, humidity and sunlight are ideal for the fungus to grow and reproduce and infect more victims. The parasite gets the insects to die hanging upside down, and then erupts a long stalk from their heads with which it sprinkle its spores to other ants. Fossil evidence recently suggested this fungus has zombified ants for millions of years.

4. The crustacean Cymothoa exigua has the dubious honor of being the only parasite known to replace an organ. It enters through the gills of the spotted rose snapper, attaching to the base of the fish’s tongue, where it drinks its blood. The bloodsucking causes the tongue to eventually wither away, at which point the crustacean attaches itself to the tongue stub, acting as the fish's tongue from then on!

5. The horsehair worm grows up inside a cricket and then drives it to commit suicide by drowning because it needs water in order to reproduce. When it's old enough to mate, the parasite releases proteins that cause the crickets to become suicidal in a very specific way: by drowning. A host cricket finds water and flings itself in. While it drowns, the horsehair worm wriggles its way out, free to hit the water.

6. Zombie caterpillar brainwashed by wasps. After being stung by a parasitic wasp, a head-banging caterpillar becomes a body guard: Here it is beating off a curious weevil to protect the cocoons of the very insect that is devouring it from inside. So, in a way, the caterpillar and cricket are no longer their original selves.

7. Parasites that can control group behavior: Tapeworm-infected sea monkeys turn bright red and swim together in clumps. So they can be more easily spotted and eaten by flamingos, which is exactly where those tapeworms like to breed!

8. The Lancet liver fluke Dicrocoelium dendriticum as an adult spends its time in the liver of a cow or another grazing mammals. Here it mates and lays eggs, which are excreted in the host's faeces.

A snail eats this excreta laden with the eggs. The eggs hatch in the snail and make their way into its digestive gland, where they asexually reproduce. They then travel to the surface of the snail's body. As a defensive maneuver, the snail walls the parasites up in cysts and coughs up the balls of slime...doing exactly what the parasites wanted it to do.

An ants gobbles up the fluke-laded slime balls. The flukes then spread out inside of the ants, with a couple of them making the insect's head as their home. When night approaches, the flukes take control. They make the ant climb up a blade of grass and hold tight, waiting to be eaten by a grazing animal. If the ant is still alive at dawn, the flukes release their control and the ant goes about its day like normal (if the ant baked in the sun, the parasite would die, too). At night the flukes take over again and the cycle repeats until the ant gets eaten by the cattle.
9. When the nematode Myrmeconema neotropicum gets into the ant Cephalotes atratusants, it does something rather unique: It makes the ant look like a berry. These South American ants are black, but they live up in the tropical forest canopy, where there are a lot of red berries. So the nematode takes advantage of this fact by making the ant's gaster (its bum) look exactly like a red berry. Infected ants also tend to be sluggish and walk around with their bums in the air, making them all the more appealing to fruit-eating birds.
10. Spinochordodes tellinii is a nematomorph hairworm that infects grasshoppers and crickets. As adults, the parasitic worms live in water and form writhing masses to breed. Grasshoppers and crickets ingest the worms' microscopic larvae when they drink the infested water.
The hairworm larvae then develop inside of the insect host. Once grown, they release powerful mind-controlling chemicals that sabotage the insect's central nervous system. The evil hairworms force the insect to jump into the nearest body of water, where it subsequently drown. Yes, the hairworms actually cause their hosts to commit suicide. The parasites then escape their deceased host and the cycle begin anew.
11. Glyptapanteles is a genus of parasitic wasp that often infects Thyrinteina leucocerae caterpillars. The cycle begins when an adult wasp lays its eggs inside of a baby caterpillar. The eggs hatch and develop inside of the caterpillar, as the caterpillar itself grows up. When the larvae are full-grown, they emerge from the caterpillar and pupate nearby. But it seems the larvae somehow induced a kind of Stockholm syndrome in their former host. The caterpillar host stops feeding, but remains close to its parasites and will even cover them with silk. If a potential predator comes by, the caterpillar will defend the pupating wasps with violent head-swings!
12. Leucochloridium paradoxum is a parasitic flatworm commonly known as the green-banded broodsac. L. paradoxum spends most of its life in the body of a bird. The flatworm breeds inside of the bird and its eggs get passed through the feathered host's digestive tract.
The bird excretes the eggs and snails eats it. In its larval stage, the parasite travels to the digestive system of the snail, where it develops into the next stage, the sporocyst. They rapidly reproduce and form long tubes of swollen "broodsacs." As the broodsacs grow, they spread out into the snail's eye stalks, preferring the left tentacle for some insane reason. Here, the broodsacs pulse green and yellow, causing the snail's eyes talks to resemble caterpillars, which birds like to consume.
But the parasite's manipulation doesn't stop there. Snails prefer the dark, so the broodsacs override this behavior and cause the snail to seek out light. Once in the light, the broodsacs twitch, becoming absolutely irresistible to birds.
13. Sacculina carcini barnacles start life as tiny free-swimming larva, but once they find their crab host, they become so much more. The female larva is the first to colonize its crustacean host — she attaches herself to the underside of a crab, forming a bulge in its shell. She then spreads root-like tendrils throughout her host, which she uses to draw nutrients.
As she grows, the bulge in the crab's shell turns into a knot. A male Sacculina then comes along and implants himself inside of his mate, where he produces sperm. The pair then continuously reproduces. At this time, the helpless, now-castrated crab essentially becomes the barnacle's servant. It stops molting and growing, and actually begins to take care of the barnacle's eggs as if it were its own. And this doesn't just happen with female crabs.
When the barnacle infects a male crab, it sterilizes the crustacean and alters its body to resemble that of a female crab by widening and flattening the abdomen. It then forces the crab's body to release certain hormones — the male crab begins to act like a female crab, even to the point of performing female mating dances. It also takes care of the barnacle's eggs.
14. The bird tapeworm Schistocephalus solidus is not one to restrict itself to a single host for too long. As an adult, it reproduces inside of the intestines of fish-eating water birds. The tapeworm's eggs get delivered to water in bird feces. Once in water, the eggs hatch into their larval stage and get eaten by small crustaceans called copepods. Sticklebacks then eat the copepods.
When inside a stickleback, the tapeworm shows its true colours. It makes the fish seek out warmer waters, which it needs to grow rapidly. And grow it does. The tapeworm can actually get so big that it outweighs its host. When it's time to make its way into a bird's gullet, the tapeworm causes the fish to transform: the stickleback becomes bolder and more solitary, which essentially makes it a more appealing prey for a fish-eating bird.
15. Like several other parasites on this list, the parasitic worm Euhaplorchis californiensis has several hosts. The worm's life begins in the horn snails found in the salt-water marshes of Southern California. Inside of their sterilized hosts, the worms produce several generations of offspring, which then leave the aquatic snail in search of killifish.
Once the parasite finds its new host, it latches onto the gills of the killifish, and then makes it way to the fish's brain cavity, where it forms a carpet-like layer over the fish's brain. Here it releases chemicals that mess with the fish's central nervous system. Infected killifish perform a complex dance routine involving the shimmy, the jerk, the flash and the surface. With these cool moves, the fish are 10 to 30 times more likely to get eaten by birds than uninfected fish. Inside of the birds, the fish breed and their eggs are excreted out, to be eaten by unsuspecting horn snails and the cycle begins again.
16. Heterorhabditis bacteriophora is a nematode that has adopted a different approach. Most parasites manipulate their hosts in ways that make them get eaten; this allows the parasite to complete its life cycle. H. bacteriophora, on the other hand, tells hungry predators to back off.
When the nematode infects an insect larva, it gradually changes the color of its host's body from white to red. This vivid color is a warning color to predators — in fact, robins avoided eating the red larva in experimental studies. The parasite needs the larva, which it liquefies and feeds on, and would actually die if its host gets eaten!

Now can you stop marveling at the process of evolution? How living beings evolve in order to survive? And how Nature selects its children and makes them flourish? Survival of the fittest?
How the weaker ones get perished there by the checks and balances are maintained to the perfection?

And how Bio-chemistry and Bio-diversity play a part in the whole process?!

Watch the spectacle and keep on wondering. But don't forget to take care of it and yourself too!

All these thoughts made me create this art work: THE SPLENDOUR OF EVOLUTION

It really amazes me to see in how many ways the living beings had evolved to survive the changing adverse atmospheric conditions they live in. The different body shapes, colours, food choices, all the Biological mechanisms behind these adaptations really fascinate me.


(Taken from http://www.kkartfromscience.com )

References:
1. http://www.scientificamerican.com/article/rage-disorder-linked-with...
2. http://www.livescience.com/933-study-cat-parasite-affects-human-cul...

3. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.01...