Freshwater snail: what kind of danger is it?

Few expect a trick from a snail. Many are accustomed to treat a little pat on these unusual animals. Who are they, these snails? And is a freshwater snail really dangerous?

Name

The snail is a representative of the animal kingdom. It is classified as a mollusk, a class of gastropods, or gastropods. The Latin name Gastropoda is formed from two ancient Greek words, the approximate meaning of which is "belly" and "foot". And the Russian name of this animal - "snail" - has old Slavic roots. It is consonant with the adjective "hollow". It turns out that each name reflected one of the features of the mollusk. Latin concentrated on the mode of movement, and the Russian language emphasized the hollow house that the animal wears on its back.

Typical structure

The snail is a typical gastropod, which has an external shell and trunk. It is amazing that the body simultaneously performs the functions of movement and abdomen. Above it is a special fold, which is called a mantle. The emptiness between the mantle and the body is called the mantle cavity. Inside it there is an entrance siphon, which lets in water, enriched with oxygen, and an outlet siphon, designed to remove the spent liquid. As you know, this applies to those snails that live in the water. If the animal is overland, then in the mantle cavity there is a primitive lung, and not gills.

Information about the species

In the nature of gastropods, quite a lot. Scientists recorded more than 110 thousand species. All of them are divided into 3 main subgroups:

• Marine species;
• Freshwater species;
• Land snails.

In fact, the division can be reduced to gill and pulmonary forms. But we will try to consider only one of the forms closer. It will be a freshwater snail.

Freshwater snails: danger

The most terrible killers on earth are not large predators, but small innocent snails. Although how can you call an innocuous animal, on account of which about 10,000 deaths annually? This is not an exaggeration. You are interested in the danger of freshwater snails? How can an animal that does not have sharp fangs and long claws kill a person? Now we will explain.

Every day a lot of garbage gets into fresh water bodies, including wastes of animal and human life. Dirty water multiplies various parasites. On the body of freshwater snails settle microscopic parasites from the genus Schistosoma, which infect humans.

Freshwater snail killer causes a terrible disease, which is called schistosomiasis. A huge number of parasites penetrate the skin and begin to multiply. According to the international classification, schistosomiasis is the second (after malaria) tropical disease in terms of prevalence in the world. It is estimated that more than 207 million people suffer schistosomiasis only on the African continent, but these are only those who could apply for help. According to statistics, 25% of the sick people die.

How does the infection occur?

Freshwater snails kill people, infecting reservoirs with schistosome larvae. It is in their organisms that the larvae undergo the first phase of development. The life cycle of schistosomes is rather complicated. People bathe, wash, drink water from infected water bodies, and sometimes just wade through them. In fresh water bodies there are snails, in the body of which sporocysts are settled, from which the cecaria develop. They exit the body of the snails and move freely in the water, penetrating through the human skin into the circulatory system. On large vessels and capillaries, the cecaria migrate into the portal vein or into the bladder.

In the process of migration, the form of parasites changes once again, they become adult male and female worms. The special composition of the protein structure of schistosomes makes them unobtrusive or even invisible to the human immune system. This makes it possible for the parasites to breed in an incredible amount. The immune reaction occurs only after the unisex individuals have mated and laid eggs. Through the intestine or bladder, eggs get back into the environment. From the water, the eggs again enter the body of the mollusks. And then the freshwater snails are killed again, continuing the cycle of development of schistosomes.

From penetration of the cicar into the skin to the development of a sexually mature specimen capable of reproduction, it takes about 65 days. The female is larger than the male. It can grow from 7 to 20 mm. Live schistosomes from 3 to 30 years, producing during this time billions of eggs.

The freshwater snail, which is a necessary step in the life cycle of schistosomes, is common in the waters of Africa, the Middle and Far East, South America and the Philippines.

How to understand that an infection has occurred

Symptoms of schistosomiasis are dangerous because they do not manifest immediately, but when a huge amount of parasite eggs accumulate in the body. Initially, after visiting hazardous areas, it is worth paying attention to the redness and irritation of the skin from contact with fresh water.

1-2 months after infection with parasites, primary symptoms appear. They are expressed in a febrile state, chills, coughing and soreness of the muscles. But most of the infected primary symptoms do not feel. They understand that they are ill only when chronic schistosomiasis develops. Symptoms of this disease are:

• Severe abdominal pain;
• Ascites, that is, bloating;
• Diarrhea with blood;
• Pain when urinating, blood in the urine;
• dyspnea;
• Coughing attacks;
• Heart palpitations, pain in the heart;
• Partial or complete paralysis;
• Mental disorders.

Examination, analysis, treatment

If, after returning from a vacation or business trip from countries where schistosomiasis is very common, a person begins to experience strange ailments, then it is necessary to immediately contact a parasitologist or infectious disease specialist. Especially if during a survey of local landmarks a person contacted rivers or lakes with water. In this case, in a pond where a freshwater snail is found, it is not necessary to swim. It is enough to sit on the shore, lowering your feet into the water, or for a long time put your hand into the water during a boat excursion.

Symptoms of schistosomiasis are similar to other infectious diseases, therefore it is necessary to pass several analyzes of feces and urine. Blood tests (PCR) show the presence of a problem only in the advanced stage of the disease, since the immune reaction does not immediately manifest itself.

In difficult cases, you may need a colonoscopy, a cystoscopy or a biopsy. To detect the degree of infection, ultrasound, X-ray, MRI and other examinations can be used.

As a treatment, a "Praziquantel" is prescribed. Dosage is calculated based on the weight of the patient, the duration of the appointment is determined by the doctor. To enhance the effect, it is possible to combine with the "Artesunat" preparation.

After the course of treatment, the patient should receive an appointment for feces and urine tests to make sure that the parasites have died.

Freshwater snails. Predator Helena

There are a variety of species of freshwater snails that live in open water and in freshwater aquariums. One of the species is a snail helen. This dangerous beauty lives in Southeast Asia. It has a bright and attractive appearance and is able to eat smaller gastropods.

The shell of Helen is decorated with contrasting bands of black and amber color. The head of the mollusk is elongated, like a proboscis. The Helen's body is speckled, it is covered with thousands of black dots. Nature has provided this dangerous predator with special lamellar protection. In dangerous situations, the snail closes the entrance to the sink with a solid "door".

Mollusks are often found as freshwater aquarium snails. They help reduce the number of algae, tadpoles, pond snails and other types of snails.

Horned snail

These freshwater mollusks belong to the famous family of Neritina. They are distributed in the southern latitudes. Occurs in water bodies of Japan, Thailand, the Philippines, China and Indonesia. Mollusc prefers estuaries of rivers with a stone or sandy bottom.

The snail has a natural protection in the form of sharp growths. Horns discourage predators trying to grab a snail.

Color shells consists of two colored stripes. One of them is yellow, the second is black. Small bright inhabitants often get to the owners of freshwater aquariums. They clean excess seaweed from snags, scenery and glasses. Horned mollusks live well with other inhabitants of aquariums, except, perhaps, only a snail of Helena.

Ampulary snail

Freshwater ampullaria is found in the waters of South America and Asia. These are beautiful multicolored mollusks with four sharp antennae on the body. The color range of the ampullar is surprisingly diverse. This is a whole family of mollusks, in which there are at least 120 species, each of which has its own color. The body of the molluscan can reach 7 cm in length. Of the characteristics of the species can be called gills and lungs. This is due to the fact that the species lives in shallow waters. Ampularia have a special process, stretching which, they can breathe atmospheric air, even being in the water.

Ampularies like warm water (up to 28 ° C) and not too whimsical in nutrition. They are suitable and frayed vegetables, and fish food, and small fish pieces. If the water in the aquarium is cold, then the ampularia will hibernate, covering the shell with a lid.

Aquarists love the representatives of this family for maintaining cleanliness in the bowl. The ampullarians pick up pieces of food that have sat down on the bottom and dead algae.

Snail of melange

This species of gastropod is spread throughout Africa and has a very extensive area. In natural conditions, prefers small ponds with a slow current. But melania does not like a stony bottom, prefers a silt pillow or sand. The basis of the diet of this cochlea is inferior algae and semi-decomposed organics. The melanion shell is elongated with a sharp tip. The color range varies from black to light brown.

In fact, any freshwater snail, the photo of which you will find, will look beautiful and attractive. However, we must not forget that these shellfish bear a huge danger. If the owner of the aquarium wants to make a similar pet, having settled it to other fish, then he should understand that it is necessary to take security measures.

Regardless of whether you caught the snails themselves or bought them in a pet store, all shellfish should be quarantined. Freshwater snails are planted in an empty aquarium (without algae and other inhabitants) and aged for about 4 weeks in a weak solution of potassium permanganate. Then the animal is washed in clean water and only after this procedure is allowed into the common aquarium. Although, remembering what a freshwater snail is dangerous for a person, it is undesirable to catch this animal in natural reservoirs. Why expose yourself to the danger of getting schistosomiasis?