Lancet Liver Fluke

• Group: Dicrocoelium dendriticum

We have known of this parasite at least since 1819, but deep study and observations were done in the 1950s by C.R. Mapes & Wendell Krull to determine how it actually worked. We knew before this that the parasite enjoyed going after sheep. However, after further analysis, it was determined that the parasite originally attached itself to a land snail. Slime balls were coughed up by the snail, which then came in contact with sheep to transfer over. Due to how it works, several cattle species can be infected.

However, humans have also dealt with this Lancet Liver Fluke parasite before too. It tends to connect to the bile ducts of humans. The infection usually only remains in these areas and we have medication to stop them. Not getting help though can cause huge problems in the body, including an enlarged liver on top of skin rash issues too. While this might one of the many body-snatching parasites that exploit their host, due to the hosts they tend to target, the Liver Fluke often can pass through its host with mild symptoms. Yet humans might see the most severe issues from one, whereas cattle might not randomly die from it at all.

Polymorphus paradoxus

• Group: Polymorphidae

The Polymorphys paradoxes happen to be yet another parasitic worm species. They tend to make hosts out of local crustaceans as their intermediate hosts. These are hosts that act as carriers for a parasite until it can be seen by its final host. In this case, a crustacean will make itself known due to being controlled by the parasite that infected it. A bird will then see the crustacean, which it will then attack and consume. With it goes the parasite, now inside the bird where it will reproduce. There is often no guarantee that a bird will just see a crustacean randomly.

Like other body-snatching parasites, the Polymorphus paradoxes will try to ensure a bird of any type will spot it. Thus, it will essentially take over the brain of the crustacean to remove it from the water or potentially ensure it is in shallow territories. This will improve its odds to be seen by the bird. However, unique among body-snatching parasites, there are not a whole lot of markers that help you indicate the parasite initially. Sure, it is there and can be seen if we view the crustacean closely but the bird would not spot any special differences.

Ophiocordyceps

• Group: Ophiocordycipitaceae

You likely know the Ophiocordyceps parasite most from the Last of Us video game series. This is essentially what turned humans into zombies that everyone had to somehow escape before being infected themselves. It is a parasitic fungus that usually latches onto various insect species, and it is mostly found in Africa. In ants, it is said that Ophiocordyceps does some pretty impressive things. Once it attaches itself to an ant, it will force it to climb up and attach itself to the underside of a leaf. It could be on any plant or tree, as long as it is at least 25 centimeters off the ground.

Once the ant does this, its purpose has been served and the Ophiocordyceps will begin to grow. Due to being done with the ant, it removes itself from the species which makes the ant die. From here, the parasite begins to grow on the leaf. After a few days, deadly spores will come out. If humans come in contact with those spores, it infects people pretty easily. It can actually take over a person’s brain if they let it remain in their system long enough. But the big thing is that these are true body-snatching parasites that could potentially make a person insane if it remains inside us for too long. This could be why LU used it for their game series.

Entomopathogenic Fungus

• Group: Fungus

Usually, body-snatching parasites that come in the form of a fungus have a tougher time connecting to things. As they have to wait until something comes along so they can finally attach to it. The Entomopathogenic Fungus is asexual, therefore does not need a mate to reproduce. Therefore, the fungi will attach to an insect’s body externally at first. From there, it’ll form microscopic spores that will wait for the right temperature conditions to make their move. Usually, a warm and humid environment allows them to grow and colonize into the insect’s body.

Typically, it goes through the insect’s cuticle, bashing its way through using enzymatic hydrolysis. This will get it inside the body where it’ll be able to develop fundal cells inside the body cavity itself. Of course, when a fungus begins to develop like this, there is really no way an insect is able to survive. This is likely due to fungal toxins that spark up as it develops. Once that happens, the spores will then form not just inside the insect but also on the outside. Obviously, the right temperature conditions will need to be present for this to happen properly. Yet once it does, the growth occurs and the process will begin as another insect crosses its path.

Jewel Wasp

• Group: Ampulex compressa

We have referenced the actions of the Jewel Wasp a few times on Science Sensei over the years. It is hard to ignore what this wasp can do. Whenever one of these female wasps mature and is ready to have little wasps, they will find a cockroach to help with that. Once they spot the best one they can find, they will sting the roach directly in the brain. That will result in the roach being paralyzed for a brief period of time. This is more than enough time for the wasp to do as it needs. While the roach is out of it, the wasp takes it back to its burrow where they implant their egg. This is usually just one egg though.

From here, the roach is able to eventually come to and leave to go back to its own home. The wasp won’t protest the move, as it wants the roach to go back to its home. Thus, it’ll follow this cockroach back to where it is staying. Once inside, the wasp will then block the entrance and exit, effectively trapping the roach inside. At this point, the egg is growing and in three days, the larva will hatch and slowly begin to eat the roach from the inside. This mother wasp was able to control everything perfectly, giving it the best outcome while the baby wasp literally took over the body. Making it one of the most notable body-snatching parasites in the world today.

Toxoplasma Gondii

• Group: Apicomplexan

Perhaps the most notable of all body-snatching parasites, the Toxoplasma Gondii is a well-known brain parasite mostly found in rats. Once a rat is infected by this parasite, it is capable of manipulating and forcing the rat to do whatever it wants. In fact, many are trying to move around to different hosts. As a result, it will push for the rat to be seen by other animals. In particular, its most notable enemy, the house cat. Thus, the rat will go literally right at the cat rather than running away as it normally would. In fact, in one study, it was found that infected rats seem to be attracted to the smell of cats overall, but in particular their urine.

Now that the rat is more often than not killed by the cat, the parasite will now move inside the cat. This gives the parasite the proper room it needs to breed and further expand. There are quite a few cases of humans getting this parasite inside of them too. It is quite likely that they might have gotten it from their own cat. It is estimated that at least 60 million Americans have come in contact with Toxoplasma Gondii. That is pretty significant when you think about how hard it is for humans to randomly get parasites. At least those of us who understand hygiene. In humans, it could likely affect our brains and heavily reproduce if we do not kill it soon.

Sources:

National Institutes of Health

Centers for Disease Control & Prevention (CDC)

University of Minnesota

University of California, Berkeley

National Geographic

Journal of Crustacean Biology

Natural History Museum

University of California