Plague Doctor

In a transparent square glass box, a snail is slowly squirming.

It is an amber snail, a kind of snail distributed throughout the country.

It originally lived in dark and moist places, such as grass, ditches, etc. It likes humidity and heat, and can tolerate drought and cold. It can also float on aquatic plants and water. It feeds on humus, lichens, fungi, moss, algae, and buds and leaves of plants.

The size of the amber snail's shell varies widely. It is usually long oval with 3-4 shell layers. The shell is 5-15 mm high and 3-8 mm wide. The shell is thin and the shell surface is light yellow or yellowish brown. , the body is transparent or translucent and shiny.

But the two tentacles of this snail in the glass box are particularly swollen. Compared with the normal amber snail, it looks like two disgusting growths.

Moreover, in its transparent body, you can clearly see some things inside, but they are not its internal organs.

Suddenly, it squirmed faster, squirming crazily at a speed that was difficult for snails to achieve.

Its two swollen tentacles reflected bright light, like two drill heads, constantly rotating, flickering and changing.

"Students, this is a snail infected with parasites. The colors and lights you see are actually a large number of parasites wriggling in its body."

In the biology class of this university, following the teacher's words, the teaching screen played a slow-motion image magnified ten times. It was still an amber snail. The students all saw the creepy details. It was indeed not a natural luster. .

The snail's body is filled with parasites, one by one, and they are constantly pushing and beating.

"Those are the two-disc flukes that change the snail's body shape and control the snail's brain."

The image on the teaching screen changed, showing two-disc flukes, parasites that looked very huge under the lens.

Some of these biology students frowned, some were curious, and some already understood.

"First, the snail eats the eggs of the diplopid fluke." The middle-aged man's teacher said, "This is how the parasite enters the host's body."

"The eggs will then develop into sporangia, which mainly parasitize in the liver of the snail. At this time, the snail still shows no abnormal behavior. Maybe even it itself does not know that there are worms in its body, and it has worked hard to eat the nutrients it has absorbed. Matter is constantly being stolen by parasites. We are not snails and we are not sure about this and how they feel exactly."

There was a chuckle in the classroom, but the students soon fell silent.

They looked at the simulated image on the screen, demonstrating how the parasite grows cercariae, then grows, branches extend outward from the snail's body, enter the two tentacles, and then form a complete sporangium, which is full of spores. It's full of larvae.

It is they that cause the snail's antennae to continue to expand so that they cannot contract normally and can only hang brightly outside.

Looking at these pictures, some students really felt that the snail parasitized by the double-disc fluke was so pitiful.

"Once it enters the eyestalk of the snail, the double-disc fluke begins to have the ability to control the host. The snail originally likes to be active at night, but after being controlled, it will become active during the day in a well-lit place, and move at the speed of a normal snail As much as three times, this may be the physiological limit of the snail."

The teacher pointed at the diseased snail in the glass box on the podium, its tentacles flashing like neon lights.

"The method by which the diplopid fluke controls snails has not yet been studied. Students, it will be up to you in the future.

But this kind of parasite is really smart. They make the snail colorful, make it lose its sense of fear, and walk struttingly in the sun. It is so eye-catching, and it can also control the snail to climb higher leaves, those special ones. Conspicuous place. for what? Just for the birds to see. When the birds saw something shiny there, it looked like a bug, they flew over and ate it in one bite. That's actually a snail's antennae, and it's full of double-disc flukes. "

The teacher paused, picked up the chalk and wrote on the blackboard, emphasizing: "Aggressive mimicry is a situation where the parasite benefits."

Aggressive mimicry is a biological concept. In short, organisms use mating promises, false food and other means to deceive prey.

For example, pitcher plants imitate flowers to trap nectar-feeding insects. Eating, surviving, and reproducing are the wisdom of nature.

"Snails are the first intermediate host." The teacher wrote on the blackboard while preaching: "Birds are the second intermediate host. After entering the body of the bird, the fluke will reproduce there, and then the eggs will follow the bird. The excrement is expelled, and the guano is eaten by other snails...and the cycle repeats."

The students had goosebumps when they heard that the double-disc fluke used snails as false food and its prey was birds.

A tiny parasite, only a millimeter in size, has such sinister and weird tricks.

And it can distinguish between day and night, high and low, conspicuous and concealed.

Whether this is wisdom or instinct, it is amazing.

"Teacher, can double-disk flukes control birds?" a male student asked.

"There is no evidence of this."

"Then can it enter the human body?"

"This is not a human parasite." The teacher smiled and said, "Our human body is more complex than snails and birds. We have a stronger defense system and can block the double-disc fluke. However, we also have many parasites to deal with, such as iron worms. It’s also very difficult to do. I know what you want to ask. No, there is no such thing as one that can control human thoughts and actions.

for parasites. "

"Maybe there is one kind of thing called money." The teacher added, "The English name is money, and the Latin name is aes."

There was another chuckle from the students in the classroom.

Indeed, humans are not snails, and parasites are not easy to control.

At the same time, in the transparent glass box, the snail was squirming crazily and squirming without moving for a second.

…

Beep, beep, the call is connected.

"Hello, are you Wang Jiawei's mother? I'm Li Yuhao's mother. Yes, our sons live in the same dormitory."

"Hello, Yuhao mother, what do you want from me?"

"It's like this. Yuhao told us last night that he and several classmates went to your house to have a party and spent the night there. I called him in the morning, but no one answered. It's almost noon now, and there's still no one. Answer, he hasn't come home yet. I also have Jiawei's number here, and several other classmates' numbers. I called them, but no one answered..."

"Is that so... Yuhao's mother, Jiawei's father and I are out of town these days. Don't worry, young people will definitely stay late at parties. There is no school today, so it's not unusual to stay up all night. Maybe They haven’t woken up yet, so no one is answering.”

"I think so too, but it's a little strange... These kids haven't posted on WeChat Moments. How could they have never posted a few messages at any gathering before?"

"Well... how about this? I'll ask the community property management to send someone to my house to see what's going on. Maybe I'm drunk?"

"Okay, Jiawei's mother, please trouble you."

"Hey, why are you so polite? This is also a party hosted by Jiawei."

The call is over.

Less than half an hour later, the call was connected again.

"Hello, Yuhao's mother? The security guard came over just now. No one was at home. He also found that my garage was open. I looked at the picture and saw that an MPV was driven away. I asked the security guard to check the surveillance of the community. , the car was driven out last night, Jiawei drove the car, Yuhao and the others were in the car..."

"What... Jiawei can drive? Here, where did they go?"

"I don't know yet, Yuhao's mother, it should be fine. The young people are just going crazy. Let's not get into trouble."

"Stop talking, call the police. Let's call the police quickly."

"Wait a minute, this matter hasn't gotten to that point yet, let's not make it big... Yuhao's mother, don't think it was Jiawei who drove the car, but you think I only care about my son. What if it's all of them who did the bad things? ? We don’t know, I mean, if, if they touch marijuana, ecstasy, etc., calling the police will destroy them, we have to think about the children."

"Hey! You... are they safe now? Isn't it the first thing we have to consider? My Yuhao is not the kind of person who takes drugs."

"I'm just using an analogy. Wait, Yuhao's mother, look at the WeChat Moments! I saw that Jiawei just posted a WeChat Moments. Can you see if Yuhao has posted it?"

"Ah, let's see, hey, yes, yes, yes! Yu Hao just sent a message. This kid is here, why doesn't he answer the phone? He doesn't even call back with a message. It scares me to death. Oh, it's true. .What does this circle of friends mean...'I have seen God, and I am its incarnation in the human world.'"

"...Jiawei also said the same thing. Did they go to a concert to see an idol?"

"Maybe, this kid... Jiawei's mother, let's do this for now. I'll call Yuhao again. When he comes home, see if I don't give him a spanking."

"Young people don't need to beat or scold him if they go out crazy, but this Jiawei, I want to deal with him when I get back."

Love the Plague Doctor.