Many patients believe that only helminths can parasitize in the human intestines. However, this is a misconception. Often in the digestive tract are the simplest microorganisms that are not visible to the naked eye. They can cause human health no less harm than parasitic worms. These protozoa include coccidia. They are found in both humans and animals. The life cycle of coccidia is very complicated, it goes through several stages. In the process of reproduction of parasites, harmful substances are released that affect the intestines.
What is coccidia?
Coccidia are single-celled protozoa. They parasitize in the small intestines of animals and humans. The microorganisms of the Coccidia squad are specific parasites. Each species of this protozoan can parasitize only in the intestines of a particular host. For example, coccidia that live in the body of a hare cannot be in the body of a rabbit.
Coccidia can reproduce both sexually and asexually. They cause a disease called coccidiosis. In humans, this disease is quite rare. More often this parasitic disease affects animals. For humans, only two types of coccidia are dangerous:
- Isospora belli. This kind of coccidia can only live in the human body.
- Isospora hominis. This type of parasite is common to humans and cattle. This type of coccidia is also found in pigs.
In Russia, cases of coccidiosis are observed mainly in the southern regions: in the Caucasus and Crimea.
Parasite structure
The parasite has microscopic dimensions and a rather complex body structure. During the life cycle, coccidia can exist in the following forms:
- Oocyst. In this form, the parasite enters the human or animal body. An oocyst is formed during sexual reproduction of a given microorganism. This form of coccidia can be called protective. It helps parasites survive until new individuals mature. Inside each oocyst are sporozoites.
- Sporozoites. This is a mobile form of coccidia. They are released from oocysts.
- Schizont. This motionless microorganism consists of several lobules - merozoites. In the process of reproduction, they turn into germ cells, from which an oocyst is formed.
Let us consider in more detail the structure of the sporozoite. This microorganism is similar in structure to a human cell. Sporozoites have a nucleus around which the cytoplasm is located. Also, protozoa contain organoids: mitochondria and endoplasm. Outside, the sporozoite is covered with a shell - a pellicle. Under it there are tubes - fibrils. These structures allow the microorganism to maintain shape. Closer to the front end of the tube, they twist and form a conoid. With its help, the parasite is attached to the walls of the intestine. Also, sporozoites are equipped with flagella for movement.
Photos of coccidia at different stages of the life cycle are presented in the article.
Life cycle
The development of the parasite begins immediately after the host enters the body. The life cycle of coccidia goes through several stages.
First, asexual reproduction of the simplest occurs:
- After entering the intestines, sporozoites exit the oocyst.
- Soon sporozoites turn into a fixed form - schizont.
- At a schizont, the number of nuclei increases. Then it breaks down into merozoites, which spread through the small intestine.
After several such cycles, coccidia begin to reproduce sexually. Merozoites turn into germ cells of two types:
- Macro-mammoths. These are original analogues of ova. They increase in size, accumulate nutrients and turn into macrogametes.
- Micro-mammoths. These cells resemble sperm. They also increase in size, they have an active fission of nuclei. Then the micro-mammoths are torn. Microgametes come out of them, equipped with flagella for advancing to macrogametes.
Then the fertilization process takes place: the microgamet merges with the macrogamet. A zygote forms. Two protective layers grow around it. So a new oocyst is formed. Then the coccidia life cycle is repeated anew.
Infection pathways
Ways of infection with coccidia differ depending on the type of parasite. Isospora belli lives only in the human intestines. Therefore, you can get infected only from the patient. Oocysts exit the body along with feces. They are very resistant to the external environment. If a person does not wash his hands after visiting the toilet, and then touches objects, then coccidia spread throughout the house. This is always the result of poor hygiene. However, there are times when the patient inadvertently flushed the toilet water, and the oocysts, along with droplets of moisture, remain on all surrounding objects.
Coccidia Isospora hominis are found in both humans and animals. Infection with this type of protozoa occurs by eating beef or pork infected with oocysts. Unheated or undercooked meat is especially dangerous. The developmental cycle of coccidia in the animal’s body is somewhat different than in humans. Parasites from the intestines can enter the muscles of animals.
Symptomatology
The incubation period of coccidiosis lasts about 1 week. At this time, the parasite attaches to the walls of the intestine. Then the patient has the following symptoms:
- General well-being worsens, body temperature rises to +39 degrees.
- Severe diarrhea occurs. In this case, feces have a watery consistency. They may contain blood and mucus.
- Vomiting occurs periodically.
- The patient feels a chill.
- The patient has weight loss due to poor appetite.
These unpleasant sensations are associated with the process of reproduction of the parasite. When sporozoites leave the oocyst, caustic substances are released into the intestinal cavity. They cause irritation and inflammation of the mucosa.
Symptoms of pathology in different patients are expressed to varying degrees. It largely depends on the type of coccidia. With infection of Isospora hominis, the disease proceeds in a more severe form than with infection of Isospora belli.
Usually the symptoms of the disease last no more than two weeks. After this, all unpleasant manifestations disappear on their own, since the active reproduction of parasites lasts about 14 days. However, this does not mean that no measures should be taken when infected with coccidia. Treatment is necessary, since the inflammatory process in the intestines can lead to serious complications.
Fatal outcomes with coccidiosis were not noted, the disease has a favorable prognosis. It is impossible to get infected with coccidiosis again, the body develops immunity to these parasites.
Diagnostics
Patients very often take signs of coccidiosis for food poisoning or bacterial gastrointestinal infection. After all, many gastrointestinal diseases have similar symptoms. Often, even experts take this disease for dysentery. To distinguish this pathology from other lesions of the gastrointestinal tract, stool analysis for oocysts is prescribed.
However, the difficulty in diagnosing coccidiosis lies in the fact that oocysts are detected in the feces during recovery. If parasites are not found in the analysis, but the patient has signs of the disease, flotation methods are used. Special solutions are added to the feces, and as a result, parasites float in the resulting liquid.
Treatment
In the mild form of the disease, bismuth nitrate is prescribed. This medication reduces bowel irritation and diarrhea. In more severe cases, the use of antiprotozoal and sulfonamide drugs is indicated:
- "Biseptolum";
- "Chloridine";
- Sulfazine;
- "Metronidazole".
Anti-inflammatory drugs are also prescribed that prevent ulceration of the intestinal wall.
During treatment, the patient must follow a diet. Spicy, salty, fried and fatty foods should be avoided.
As an addition to drug therapy, folk remedies can be used:
- Decoction of celandine, chamomile and St. John's wort. Herbs must be taken in equal proportions. The drug is taken in the morning on an empty stomach.
- Garlic and flax seeds. They can be consumed in pure form. These products have antiparasitic properties.
- Green tea. You need to cook a very concentrated tea leaves. It is taken 1 teaspoon three times a day.
Prevention
Coccidiosis in humans is very rare. Therefore, specific prevention has not been developed. However, given the route of transmission of parasites, it is recommended that you wash your hands regularly and observe personal hygiene. Beef and pork must be thoroughly cooked. You must also purchase meat only from trusted manufacturers. These measures will help to avoid unpleasant manifestations of coccidiosis.