Sarcocysts are one-celled parasites that cause sarcocystis – a serious disease of human beings and farm livestock. There are about 90 species of sarcocysts. They cause two types of the disease – virulent type and chronic type, when sarcocysts invade muscle cells. There they can live for years without any visible clinical implications: animal chronic sarcocystis can be identified only after death. That’s why scientists have an unsupported theory that in the course of long coexistence animals and their intracellular parasites get used to each other. Parasites are quietly sitting in the cell, and chronic sarcocystis can be regarded as a slow process not worth veterinary attention.

The scientists knew that chronic type never turns to a virulent one and never worried about infected livestock. But recently the infection turned massive: according to postmortal diagnostics 70-100% of livestock are infested with sarcocysts. That is why these parasites now require serious attention.

Scientists from Cytology Institute have studied muscles of artificially infested laboratory animals and ill cows, buffalos and sheep and gave a detail description of changes made by parasite. First, an inflammation near an affected muscle fibre (one fibre is one cell) starts. The cells swell, and feeding capillaries slowly collapse. Nerve endings near the muscle fibre start to die, which leads to muscle atrophy – cells slowly deteriorate. Parasite influence slowly spreads to neighbouring muscle fibres and even to connective tissue cells. Sarcocysts live not only in skeletal muscle cells, but also in other muscles, in the tongue or heart, for example.

Cells death should, of course, attract attention of immune system of the organism, which eliminated dead tissues together with parasites, which dwell there. But antibodies hardly visit muscle tissues, and cellular debrises are consumed by sarcocysts, hiding their presence in the organism. That’s why parasites can peacefully invade cells for years, without any immune response of the infected organism. This all ends in total damage of the organism. Farm livestock evidently do not live to see all this, but meat of animals with chronic sarcocystis has low quality and is sometimes dangerous for human beings.

Sarcocysts have complex lifecycle. These parasites have two hosts – intermediate (nonpredatory animal) and final (predator). Sarcocysts propagate in intestinal cells of a final host, mostly cats or dogs, and come outside with host’s excrements. Then they get to the herbivore’s (cow, buffalo, horse, sheep, goat or pig) or bird’s organism. Infesting leads to the virulent type of the disease: appetite disappears, thermometer is going up, snuffle, dyspnea and dystaxia appear. If the host survives, parasite moves to his muscles and the disease turns chronic. Final hosts – carnivores – get infested after consuming meat of intermediate hosts and also have virulent sarcocystis.

Of course, readers want to know about humans. For sarcocysts a human being can be an intermediate host, as well as a final host, depending on the species of the parasite. Different species of parasites infest different farm livestock. Through their meat one can be infested only with these species, for which this animal is the final host. One can be protected from the disease by keeping the fundamentals of hygiene.