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Coccidia
Last reviewed: 23.04.2024
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Order of coccidia
A detachment of coccidia is a fairly broad group of protozoan parasites, which number about 400 varieties. They take root within various living organisms: inside worms, arthropods, etc. Coccidia penetrate the cells of tissues and organs, and some species can parasitize in the body of pets, birds and certain species of fish.
Only one variety of coccidia can affect the human body.
Coccidia are able to reproduce sexually and non-sexually, thus a generation change occurs, which is sometimes accompanied by a change in the host (host). Most often, the parasite stops and develops in the intestinal epithelium, bile ducts, liver tissues, blood cells and endothelial cells.
A detachment of coccidia is considered a narrowly specific parasite. This is due to the fact that almost all of their varieties are held by the same host, but are not capable of parasitizing even in approximate and similar types of hosts. For example, parasites that infect a rabbit are unable to hit a rabbit, and vice versa. Inside the host, coccidia do not parasitize the entire body, but adhere to certain "favorite" sites. For example, the entire intestine of the coccidium does not strike, but only certain of its departments.
Structure of coccidia
The adult generation of coccidia has a round or oval shape. Their structure is quite complex, especially at the mobile stages of development.
On the outside, the coccidia is covered with a multilayered pellicle, under which there is a tubular fibrillar system, or so-called subpellicular microtubules. Together with the shells, they form the outer skeleton of the zoo.
The outer shell of the pellicle is holistic, and the underlying layers have interruptions in front and behind, at the location of the rear and front support rings. On the inner circle of the front ring is a specific cone-shaped dense structure - a conoid, with walls in the form of spirally folded fibrils. The function of the conoid is the support at the moment the zoe enters the host cell.
The anterior 1/3 of the zoe are tube-like structures with an extension from the inside-the roptria. Their edges pass through the holes of the conoid. Presumably, the function of the dropsy is the release of a substance that facilitates the entry of the zoo into the host cell.
The anterior end of the merozoite contains dense, curly strands - micrones. Their functions are still unclear.
In addition to the structures listed above, the components inherent in all cells are also observed in the cytoplasmic layer of the zoits. These are mitochondria and endoplasm with ribosomes, the Golgi complex. There are other components: carbohydrate, protein and fat particles, which represent a reserve of energy resources.
The life cycle of coccidia
The life cycle of coccidia begins from the moment when it enters the intestine of the host. The first stage of this cycle is the formation of sporozoite, which leaves the swallowed (eaten) oocyst. Sporozoite is a small cellular formation in the form of a spindle, which has one nucleus. Sporozoite immediately penetrates into the epithelial cells of the intestine, where they immediately acquire a rounded shape and become like a ball. Then the active development of the parasite begins: it increases in volume in a short time. The coccidia feeds osmotically. At this stage, coccidia is called the term "shizont", which characterizes its method of reproduction.
The cycle of development of coccidia passes the kernel fission period: the schizonont takes several nuclei instead of one nucleus. Their number can range from eight pieces to sixty. Developing schizonont develops a cell of the epithelium and gradually passes into the subepithelial connective tissue layer. The cycle of development of a schizont ends with asexual reproduction. The circumference of each individual nucleus is determined by the cytoplasmic zone, as a result of which the schizont decays into mononuclear cell structures of a spindle-shaped shape. Here, asexual reproduction of a schizont comes to an end: it is also called multiple division or schizogony. The described cycle lasts approximately 90 hours. The resultant spindle-shaped cells are called the term "merozoites".
Merozoites again find themselves in the cells of the intestinal epithelium and continue to multiply: the next generation of schizonts is born. This process takes a little longer - about 120 hours. The second generation, in turn, generates the third. Those merozoites that are unable to form schizonts, contribute to the birth of gametes (sex cell structures). Such cells have a clear division into male and female macrogametes.
Fertilization is the most important stage in the development of coccidia. The interaction of micro- and macrogamets occurs with the formation of an inner shell, with the zygote appearing in the lumen of the intestine. This zygote with a two-layered membrane is called oocyst.
Further, the internal stage of parasite development ends, since oocysts require oxygen for vital activity. For this, the oocyst of coccidia must leave the host's intestine.
Coccidia in humans
In humans, coccidia are very rare: single cases of infection have been recorded in Uzbekistan, the Caucasus, and the Crimea.
A person can be affected only by the coccidium Isospora belli or Isospora hominis. Great value in infection of the person can play pets, at simultaneous non-observance of rules of personal hygiene. The patient becomes the owner of the parasite when ingested with products or liquids of oocysts, which subsequently begin to be excreted with faeces of the diseased coccidiosis. For several days, the coccidium ripens in soil conditions.
In the intestinal cavity in the human body, sporozoites are released from the oocysts. Further they penetrate into the epithelial tissue with its subsequent destruction. An inflammatory process develops, in some cases ulcerous surfaces are formed. There is fever with a fever of 39 ° C, general weakness, lack of appetite, stool disorder, apathy, drowsiness.
The disease (coccidiosis) can last several weeks, or up to 1 month. Having recovered from coccidiosis, a person can allocate coccidia oocysts with feces for a month already.
Repeatedly, a patient who has had a certain type of coccidiosis can not get sick.
Coccidia in cats
Coccidia in cats are more common than in humans. Moreover, kittens are more prone to infection, although adult individuals suffer from coccidiosis. Cats are mostly affected by coccidia such as Isospora felis or rivolta.
Under what conditions can the cat get infected:
- by feces of parasitic individuals (oocysts in the feces of other cats);
- as a result of eating contaminated foods, for example, raw fish;
- when eating caught rodents or birds affected by coccidia.
Coccidia settle in the intestines of the animal, where they develop and multiply. Outwardly, the disease manifests itself as an enterocolitis, and in young individuals and kittens the disease is more difficult.
The main symptoms of infection: diarrhea (feces with mucus, in some cases even with blood), anemia. The animal becomes sluggish, refuses food, loses weight.
If you are suspected of coccidiosis, you must go to a veterinary clinic.
Coccidia in dogs
Coccidia affecting dogs are Isospora canis or I. Ohioensis. The defeat of coccidia, in the first place, is characterized by a violation of the digestive processes, thinning, which can subsequently lead to the death of the dog.
Settled parasites mainly in the posterior third of the small intestine, after swallowing the pathogen by the dog.
In puppyhood, the disease is particularly acute, sometimes with the defeat not only of the intestine, but also of the animal's liver. There is vomiting, diarrhea, increased temperature, bloating.
Of great importance in the infection of animals with coccidia is unsanitary and numerous carriers of parasites, such as flies, rodents, birds.
In most dogs, when examining a feces, attention is drawn to the change in the color of the stool (with a green tinge, dark, grayish, yellow, etc.) and odor, which indicates an active multiplication of the microflora in the intestine.
In some cases, coccidiosis is combined with helminthic invasion.
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Treatment of coccidia
The scheme of treatment of coccidia in humans is not developed due to the fact that this disease is extremely rare. Cases of the disease are rare for many decades.
Ill animals should be isolated. For their treatment use:
- sulfonamides;
- nitrofuran (furazolidone);
- antifungal (nystatin);
- antiprotozoal (sarsols);
- preparations of silver (albargin);
- tetracyclines;
- Levomycetins (synthomycin), etc.
The most common are:
- sulfadimethoxin 5 mg / kg, mixed in the feed, for 4 days;
- norsulfazole (phthalazole) 3-5 g / kg with liquid, 2 times a day for five days;
- solutions of iodine with water for drinking, iodinol, etc .;
- furazolidone and furacilin 2 g;
- coccidin 0.05 g / kg for 4 days.
The treatment is aimed at the breakdown of proteolytic processes in cellular structures and the inhibition of the consumption of para-aminobenzoic acid, which leads to disruption in the growth and reproduction of coccidia, as well as damage to the ability of parasites to release toxins.
Separately, drugs can be used to prevent anemia and restore the body's immune defenses.
Prevention of coccidia
Prevention of coccidia is to observe the following rules:
- adherence to sanitary and hygienic measures;
- maintenance of cleanliness in premises where animals are kept or bred;
- high-grade feeding of young animals, puppies, kittens.
If a sick animal is found, then it must be isolated and treated, withstood the interval of the incubation period.
For some species of animals, a prophylactic vaccination against coccidia is provided, which can protect the pet from several varieties of the parasite. Find out about the availability of such vaccines and the possibility of using vaccination at the nearest veterinary clinic.
A person can protect himself from infection with coccidiosis by simply observing sanitary and hygienic norms. This is a frequent washing of hands, eating only washed or heat-treated vegetables and fruits, maintaining cleanliness in residential and subsidiary premises. Much attention is paid to nutrition: the food should be fresh and balanced, and drinking water - clean and recruited from known proven sources.
It has been proved that coccidia from domestic animals can not be transmitted to humans, but adherence to elementary hygiene rules when keeping the animal is mandatory.