Mollusks

Molluscs (spineless) - one of the types of invertebrate animals living in marine and fresh water and on land. The major classes: bivalves, gastropods and cephalopods. The body of the soft clam, non-segmented, for the most part covered with a sink.
Many molluscs (oysters, mussels, scallops, squid and others) used in food. Clams have certain medical importance, as edible molluscs, residing in contaminated water, acquire toxic properties and can cause food poisoning (treatment in these cases symptomatic); concentrating in his body the various bacteria, shellfish can be a source of infectious diseases, including typhoid fever.
Some species of gastropods are intermediate hosts of parasitic worms class flukes (Lancet Fluke, fasciolae, opisthorchis, schistosomes and others)contributing to the spread them among the people and animals (see the Trematodozov). For the extermination of harmful shellfish resort to burning of pastures, drainage of wetlands, use copper sulfate and various organophosphorus drugs - molluscicides, as well as some antibiotics, such as Milutin.

Molluscs (Mollusca; from lat. mollis - soft - one of the types of invertebrate animals originating in the process of historical development from worms. Type M has more than 105 thousand species. Shellfish - dvustoronnesimmetrichnye animals in which, however, due to the secondary displacement authorities often pronounced asymmetry. The body soft, undifferentiated, surrounded skin fold - mantle-emitting shell. Body - leg - is an unpaired muscular outgrowth on the ventral side of the body; its homologue in floating marine forms "funnel". M live in fresh and sea water, and on land (Fig.).
Type M includes several classes, of which the most important are: folding, or plastination, gastropods and cephalopods. The bivalve head is reduced, the body consists of a body and legs, sink symmetric. Gastropods presents the greatest number of species. Head their separate from the body, the foot - wide politeley sole, sink - asymmetric, sometimes reduced. Cephalopods are the most highly organized shellfish.
Dvustoronnyaya body is divided interception on the head and torso. Mouth surround 8-10 tentacles with suction cups. Sink most forms reduced.
Many species of edible mollusks. Nutritional value of meat M large. In extracts from the muscles cuttlefish and octopus detected amino acids: glycine, alanine, valine, leucine, isoleucine, serine, threonine, methionine, aspartic acid, glutamic acid, tyrosine, phenylalanine, Proline, tryptophan, arginine, lysine, histidine. Meat oysters contains vitamins a, b and C; in the ashes discovered phosphorus, sulfur, calcium, iron, copper. In the meat of mussel and freshwater bivalve found a significant number 7-dehydrocholate-Sterol - provitamin D3. Sink some flour is used for different kinds of products. Some representatives of bivalve - suppliers of pearls. From "ink sack" cephalopods - special gland opening in the rear rectum, mined watercolour paint Sepia. Various species of gastropods Meters are pests of agricultural crops. The bivalve mollusk "ship worm" protecive moves in submerged wooden parts of ships and various port facilities.
The role of M in the epidemiology and natural focality of worm infestation is determined by the fact that many Meters are intermediate hosts of a number of parasitic worms: Fasciola hepatica (see Fasciola C), Dicrocoelium lanceatum (see Dicroceliosis), Opisthorchis felineus (see Opistorhoz), Paragonimus westermani (see Paragonimoz), as well as agents of schistosomiasis (see), etc. While in contaminated seawater edible bivalve M (oysters, mussels) buy toxic properties, vanishing in keeping them clean sea water; concentrating in his body the various bacteria, edible Meters can cause infectious human diseases, including typhoid fever. The destruction of harmful freshwater M contribute hydrotechnical works. To this end, apply various chemicals.
During the examination of lesions epizootic outbreaks or epidemics, distribution and maintenance of which is connected with clams, you must determine what types of Meters to live in the affected area, and also to establish the degree of involvement of each species to spread and maintain invasions. One of the necessary conditions for the eradication of invasions, distributed by certain kinds of Meters, is the destruction of these species, held in parallel with deworming population or Pets.
For the extermination of harmful shellfish tested different methods: physical destruction, the action of toxic substances - molluscicides, biological control. In southern Kazakhstan for the extermination of land snails - intermediate hosts for worms, parasites of livestock, is applied burning of pastures. As molluscicides, suitable for the destruction of freshwater snails, mainly the distribution of schistosomiasis, has long been used copper sulfate (Middle East countries and other); the distribution of human fascioliasis is a small pond snail - destroy the liming of wetlands, pools, ditches and other habitats of the snails (C. I. Cormorants, V. Ya. Pankratova). After many laboratory and field experiments was made the selection of the most toxic to M. chemicals (pentachlorophenolate sodium, pentachlorophenolate copper and others), which have been used to kill the snails on relatively large areas in Japan, the Philippines, Central America. Preliminary tests molluscocides action of organophosphorus drugs on freshwater molluscs, produced in our waters, showed high toxicity of tetraethylpyrophosphate (piropos) and tetraethylpyrophosphate (titeofas), which in the concentration of 0,00001 kill the snails and coils in the period from 3 to 13 days (C. C. Vannikova). With regard to biological methods of struggle with snails, while they are only under study. Such, for example, experiments using some catfish fish for the destruction of snails in fishponds in the Congo, and the first experiments of infection Egyptian snails (distributors of schistosomiasis) Bacillus (Bacillus pinottii), the detrimental effect of which was set against tropical snail Australorbis glabratus (E. Dias, M. Dawood). Very highly toxic for the snails were some antibiotics, such as Milutin, rimoldi, anatomical; the most toxic Milutin, destructive acts on M in dilution 1 : 4 million [Seneca, Bergendal (N. Seneca, E. Bergendahl)].

Mollusks: 1 - bezzubko (Anodonta cellensis); 2 - the common pond snail (Limnaea stagnalis); 3 - poisonous snail (Conus grographus); 4 - mussels (Mytilus edulis; and - leg; b - string);.5 - Zebrina hohenackeri; 6 - a small pond snail (Limnaea truncatula); 7 - Bythynium leachii; in - Melania amurensis.