It's time to eat hemp again.
Figure from the network
Among the many crayfish, it is not excluded that sick crayfish will mix into the streets and alleys, and if you want to eat openly with confidence, it is necessary to understand what they look like.
Today, Tadpole Jun took stock of 5 kinds of sick crayfish, let's take a look.
【Patient Profile】
crayfish
The picture is from the wiki shared resource
Crayfish: The scientific name is protocampus crawfish, although it belongs to the same crustacean as lobsters, and looks "bumpy face", but crayfish do not belong to the lobster family, but belong to the cockroach family known as "river shrimp", most of which inhabit freshwater rivers and lakes.
The homeland of crayfish is in North America, first introduced by Japan during World War I, introduced to China by Japan in the 1930s, initially played as a pet, and later found that its meat is tender and unique, and it is served on the table and becomes a popular summer delicacy.
1
Patient No. 1
Doctor: Where is it uncomfortable?
Patient: These days, I always feel that my whole body is not energetic, and I feel very tired after climbing a few times, especially I feel that it is more and more difficult to breathe.
Doctor: How about diet?
Patient: I have no appetite for anything.
(The doctor looked at the patient's "gills" and found that it was slightly brownish, and the color of its shell was not as red and bright as a healthy crayfish, but whitish...)
Crayfish disease No. 1: Black gill disease
The picture is from China Aquaculture Network
【Medical Record Book】
Diagnosis: The gills of the patient are pale brown, some parts have even completely turned black, and the gills have a tendency to shrink; their body color is abnormal, white. Combined with the patient's own description, the patient's body weakness, inactivity, and slow movement, or crawling slowly under the water, or clinging to aquatic grass to the surface of the water, the diagnosis is black gill disease.
Causes: Black gill disease is caused by serious water pollution, crayfish gills are infected by fungi; in addition, if the guardian (shrimp farmer) ignores the vitamin C supplement in his diet, it will also lead to the occurrence of black gill disease, if not treated in time, the lesions of the patient's gills will continue to worsen, and eventually they will die due to breathing difficulties.
【Risk of accidental ingestion】
Black gill disease in crayfish is triggered by fungal infections. There are about 300 species of fungi that can cause pathogenicity in the human body.
Some of these fungi invade skin, nails or hair; some attack people's internal organs and mucous membranes; some also point their finger at digestive organs (such as fungal enteritis caused by fungal infections), and we are not sure which fungus causes crayfish black gill disease, increasing the risk of human accidental consumption of crayfish with black gill disease.
2
Patient 2
Doctor: Where is it uncomfortable?
Patient: Doctor, I suddenly felt weak feet a few days ago, I had no strength to walk, I hadn't eaten for several days, and ah, you see how there is a little blood oozing from my chest?
Doctor: Come, get closer, and I'll look at your head and chest.
(The doctor found that the patient's gills were also slightly black, there was a slight bleeding phenomenon on the head and chest, the most obvious was that there were some white spots on the chest, and after doing chest X-ray, it was found that there was some unknown accumulation of water in the chest)
Crayfish disease No. 2: Viral disease - leukoplakia syndrome
The picture is from the watermark
Diagnosis: the patient's gills are blackened, there is a slight bleeding phenomenon in the chest and head, and there are some more obvious white plaques on the chest, through the physical examination of the whole body, it is found that there is yellowish water in the chest cavity, the liver and pancreas are slightly enlarged, and combined with the symptoms of the patient's weak hands and feet, slow movement, loss of appetite and other symptoms, it can be diagnosed as leukoplakia syndrome caused by viral infection.
Once the disease occurs, the mortality rate is extremely high, and it will infect adult shrimp first, and infect juvenile shrimp in the later stage.
Cause: Leukoplakia syndrome is caused by viral infection, the peak period of incidence is from April to May every year, mostly prevalent in the Yangtze River Basin. The main inducement is that the "residential density" of crayfish is larger, which leads to the deterioration of the living environment (such as shrimp body stabbing each other, excrement, residual food, shrimp shells and plankton carcasses can not be decomposed and transformed in time, resulting in a significant decrease in the amount of dissolved oxygen in the water body), the increase in living temperature and the increase in sunshine.
Leukoplakia syndrome in crayfish is caused by viral infections, and humans are also at risk of food poisoning after consumption, the most common of which is gastrointestinal discomfort such as nausea, vomiting, abdominal pain and diarrhea, and in severe cases, watery stools are excreted. Moreover, the incubation period of food poisoning is short, and the disease is rapid, which catches people off guard.
3
Patient 3
Doctor: Oh hey, what's wrong with your tail?
Patient: Whoops, Doctor, my tail is rotten, it's all rotten, will I rot and die?
Doctor: Don't worry, tell me if you've been fighting with other crayfish these past two days?
Patient: How do you know? I got into a fight with a neighbor over a small matter that day, I didn't pay attention, the tail was punctured by its pliers, and then it began to decay slowly...
Crayfish Disease No. 3: Rotten tail disease
Diagnosis: The patient's tail is severely ulcerated, combined with his self-described experience of fighting with neighbors, his tail being clipped by neighbors, and then rotting, can be diagnosed as tail rot. At the beginning of the patient's infection, there are only water sores on the tail, and the tail edges are ulcerated and necrotic; as their condition worsens, the ulceration of the tail edge gradually evolves into an ulcer in the middle of the tail. When the infection is at its worst, the entire tail of the patient even ulcerates and falls off.
Cause: The direct cause of the disease is caused by killing and fighting between crayfish, resulting in tail injury infection; sometimes also because the tail is infected by chitin decomposition bacteria.
Crayfish rot tail disease is caused by bacterial infection, there is a certain risk after human accidental ingestion, pathogenic bacteria invade the blood circulation, grow and multiply in the blood, and produce toxins, thereby triggering acute infection of the whole body, may produce rashes, joint pain and other symptoms, such as if the treatment is not timely or even cause sepsis.
4
Patient 4
Doctor: Why wrap a piece of cloth, take it away, we have a disease to see a doctor.
Patient: I'm afraid to scare you, you see that my whole body is almost covered with brown hair, what's wrong?
Doctor: Well, your head and chest are faintly blackened, do you think that you have secreted a lot of mucus on the surface of your body recently?
Patient: Yes, Doctor, because there is too much mucus, all the dirty mud is hanging on the body.
Doctor: Do you feel some difficulty breathing these two days?
Patient: It's okay, but with more hairs on the body, it's really harder to breathe.
Crayfish disease No. 4: Ciliate disease
Diagnosis: The patient's fertilized egg surface, several pairs of appendages, gills and other parts are covered with brown or yellow-green villi, resulting in emaciation and weakness of movement, the head and chest are blackened; combined with the patient's own body surface secretion of excessive mucus, the whole body is full of dirt, and the degree of breathing difficulty is aggravated with the increase of villi, and other symptoms, the diagnosis of ciliate disease.
Causes: Ciliate disease is caused by parasites such as bellworms, oblique tube worms, and twig insects, and its pathogens will multiply in large quantities and rapidly in the body of crayfish, with a shorter cycle, about 2 to 3 days can be spread throughout the body, these dense "villi" will seriously affect the normal breathing of crayfish, resulting in a large number of deaths.
Ciliates are a parasite that can parasitize the gills and intestines of invertebrates and vertebrates, although humans have characteristic colonic pouches as hosts. However, the dead ciliates that reside in the crayfish can also spoil the crayfish, which may cause gastrointestinal discomfort after accidental consumption.
5
Patient 5
Doctor: Slow down, slow down, the waist is "misplaced"?
Patient: Yeah, I was going to go to the plaster cast, but it hurt me to death, and I felt like I was about to break into two pieces.
Doctor: No need to cast, it's not "molting", I will give you a prescription, and you will get better soon.
Patient: Thank you so much.
Crayfish No. 5: Molting
Diagnosis: the disease is more obvious, there is a crack between the head and chest and the abdomen, and the whole body is darker than normal shrimp, so it can be judged as "molting", which is more common in the weakest period of crayfish molting.
Causes: Molting is mainly due to the lack of adequate calcium in time during the growth of crayfish.
In addition to calcium deficiency, the reason for the failure of the molting shell is also related to the excessive salt of the pond water and the poor water quality. Therefore, the accidental consumption of crayfish that does not molt is likely to cause excessive salt intake.
This article is the original article of tadpole staves
Author: North Sea dive deep cold
Tadpole staves
Focus on authoritative, interesting, and life-friendly Internet science communication