When you think of the world’s most dangerous animals, chances are you picture sharp-toothed creatures like lions, snakes, and sharks. But what if you found out one of the planet’s deadliest creatures can’t even bite you—and they could fit in the palm of your hand?

Believe it or not, one of the deadliest animals on Earth is far smaller than a great white shark (sorry, Jaws). These teeny, freshwater critters might appear harmless, but once you learn about the brain-controlling “zombie” parasite many of them carry, you may never take a dip in a lake again!

Most people would probably put animals like lions, snakes, and sharks at the top of any list of deadliest animals. Yet, while those animals are certainly dangerous, there’s actually another creature out there that blows them out of the water.

This super dangerous entity actually lives in fresh water—and it’s small enough that it could fit in the palm of your hand! Not that you’d ever want to get that close to this little guy, of course…

Get ready to meet the tiniest terror alive: the freshwater snail! That’s right; these tiny mollusks can be found in lakes and ponds all over the world, and they’re considered to be one of the world’s deadliest creatures. But how?

While some freshwater snails are totally harmless, many others carry something that kills more than 200,000 people a year. That’s more than any predatory mammal! So, how do they do it?

Dangerous freshwater snails carry a harmful parasite called cercariae that causes the disease schistosomiasis, or “snail fever.” It might sound like the latest dance craze, but this isn’t something you ever want to face.

The fever can’t just be avoided by steering clear of the snails in the water, either. That’s because the snails release the parasite in its larval form into the water, where it can penetrate the skin of anyone who comes into contact with it.

This cercariae larva is transferred from the snail directly to the host, and then it eventually finds its way back to the snail again to continue the entire cycle. It’s a process that’s just as effective as it is dangerous.

The parasite actually takes over the brain functions of the snails, essentially turning them into mind-controlled “zombies.” Because of this parasite, snails literally become the “trailing dead.”

The parasite uses this mind-control technique to prolong its host’s life for as long as it can. While eternal life might sound like a good thing, that’s not the case here. Once the parasite enters a snail, it has full control of their body.

The parasite uses its host to locate a new host so it can lay more eggs and multiply while feeding off the nutrients provided by its victim. It’s like a monster movie—only instead of the undead racing towards you, it’s an otherwise unassuming zombie snail.

Suzanne Sokolow, a disease ecologist, spoke about this snail fever. She said, “Schistosomiasis eggs can lodge in different tissues and cause severe symptoms ranging from anemia and fatigue, all the way to various severe symptoms.”

If these symptoms sound terrifying now, you won’t want to know what comes next. Suzanne went on to reveal the true terror of snail fever: “It can even cause death in about 10 percent of chronic cases,” she said. Yikes!

Schistosomiasis is most prevalent in poor countries that don’t have the same strict water sanitation laws as many other places do. It’s especially rampant in many parts of Africa and other countries with limited access to safe drinking water.

In places like this, the water that is available isn’t safe enough to drink or bathe in. However, because many people live in extreme poverty, they have no choice but to do it anyway—putting themselves in terrible danger.

These deadly parasites don’t need water to infect human bodies, either. People can become sick from contaminated snails that are used for food, or escargot. While most snails are perfectly safe to eat, that definitely isn’t the case for snails infected with this parasite!

When large batches of these freshwater mollusks are gathered for meals but aren’t cleaned thoroughly, the parasites enjoy an easy entry into their new host. You can’t taste the parasite, so you have no way of knowing it’s inside of you!

The symptoms of schistosomiasis are extremely unpleasant. The host’s skin will break out in itchy red bumps at first, depending on where the parasite laid its eggs. And it only gets worse from there…

Sufferers could also experience side effects like severe abdominal pain, diarrhea, and traces of blood in their urine and stool. To think you could get all of that simply from a tiny snail!

It’s hard to believe that something as small and seemingly harmless as a freshwater snail can have such a deadly impact on so many people worldwide, but it absolutely can. That’s why it’s so important to share this information…

There are treatments for schistosomiasis, but experts say the most effective way to combat this problem would be a call for better sanitation regulations in the affected areas. Until then, you know what to do if you see a zombie snail…

Yikes! The next time you head to a pond or a lake to take a dip, definitely keep an eye out for these little guys. You don’t want to catch snail fever!

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