Protozoan parasites in humans are the cause of protozoal infections (or protozoa). These diseases are contagious and threaten serious complications and consequences. Therefore, protozoa requires timely diagnosis, accurate identification of the cause and appropriate treatment.
What are protozoan parasites
This is a group of single-celled microorganisms that are unable to produce nutrients on their own. They use other creatures in the process of life, causing them serious diseases. The most common human protozoan parasites are listed below:
- flagella - giardia, leishmania, trichomonas, trypanosoma;
- sarcopal - dysenteric amoeba;
- ciliates - bursaria, balantidia;
- sporozoans - malarial plasmodium, coccidia, piroplasm.
Trypanosoma
The simplest parasite whose life cycle takes place in the body of an ungulate (antelope) or an infected person. Carriers are tse-tse flies, which, when bitten by a person, inject saliva with protozoa into his skin.
Note!
About 400 trypanosomes need to be introduced for the development of the disease (African trypanosomiasis or sleeping sickness). With one bite of a fly, up to half a million parasites fall.
Characteristics of parasitism and disease:
- trypanosomes initially circulate in the bloodstream of an infected person, causing trypanides on the skin (swelling of the face, eyelids), fever up to 40 ° C, swollen lymph nodes;
- then single-celled parasites migrate into the cerebrospinal fluid, causing drowsiness, iridocyclitis, chronic fatigue, lethargy, speech disorder, coordination;
- advanced forms of trypanosomiasis are characterized by limb convulsions, epileptic seizures, nervous and physical exhaustion, respiratory paralysis, coma and death.
Romanovsky-Giemsa test, immunofluorescent reaction, enzyme immunoassay (ELISA), lymph node puncture are used to diagnose trypanosomiasis. Confirmation of the diagnosis is often carried out by introducing the blood of a sick person to laboratory pigs. Treatment for sleep disorders involves taking special medications. In the absence of therapy with a high degree of probability, the patient's death is possible.
lamblia
Microscopic protozoa (synonyms - giardia or giardia) with four pairs of flagella are full-cycle parasites in the human body. Under certain conditions, they cause giardiasis. Giardias are attached to the wall of the small intestine with a large pump, often settling in the ducts of the liver, gallbladder and other internal organs.
Note!
Protozoan infection occurs through food, water, and unhygienic conditions. Giardia cysts with embryos remain invasive in the environment for a long time (up to 3 months in fresh water, up to 4 months in sewage). Diagnosis of protozoa is made by microscopy of cysts and adults in feces, blood, detection of antibodies in the ELISA study.
Leishmania
These flagellated protozoa cause leishmaniasis, which is common in tropical and subtropical countries. The infection occurs in a transmissible way - a bite with the saliva of bloodsucking insects, animals (dogs, squirrels). Carriers can be mosquitoes, gnats, reptiles, ticks. There are two types of leishmaniasis in humans:
- skin and mucocutaneous form (pendinskaya ulcer) - leishmaniasis lives and multiplies in human skin, causing inflammation, swelling, ulceration, trophic ulcers, damage to the respiratory tract;
- visceral form - leishmaniasis settles in internal organs (spleen, liver, lungs, heart).
A characteristic sign of cutaneous leishmaniasis is the formation of brownish nodules (leishmaniasis) at the site of insect bites. They are then replaced by round, difficult-to-heal ulcers with purulent exudate. The disease lasts for 1-2 years, leaving scars on the skin. In visceral form, leishmaniasis causes dysfunction of the adrenal glands, kidneys, liver and spleen. When diagnosed with leishmaniasis, they are found in the bone marrow, lymph nodes, skin and blood shavings.
Note!
Treatment for leishmaniasis includes quarantine measures, patient isolation, and medication.
Trichomonas
These are the simplest parasites of the human internal environment that are transmitted sexually, through household contact or as a result of a mother-to-child birth infection. There are oral, intestinal and urogenital variants of Trichomonas. Protozoa are the cause of trichomoniasis / trichomoniasis. Urogenital trichomoniasis of the genitourinary system is widespread. The chronic form of the disease threatens impotence and permanent infertility. Characteristics of trichomonas parasitism:
- body size - up to 18 microns, moves quickly thanks to moving flagella;
- drug-resistant, which determines the chronic course of trichomoniasis;
- they die quickly in the environment, in the air, under direct sunlight;
- they stay on wet rags, sponges, towels, soap dishes for a long time;
- frequent infections during sexual intercourse of vaginal, oral-vaginal type;
- Trichomonas contributes to the development of candidiasis, vulvitis, chlamydia, gonorrhea, cystitis.
The diagnosis of trichomoniasis involves the detection of trichomoniasis in genital swabs. Treatment includes the use of drugs, treatment with antiseptics. Therapy is performed in both partners to avoid recurrence. Prevention of urogenital trichomoniasis includes measures that are recommended for all sexually transmitted diseases.
dysenteric amoeba
This sarcode microorganism is a parasite that causes dangerous diseases in humans. There are two forms of dysenteric amoebiasis - intestinal and extraintestinal (hepatic or pulmonary). The disease begins 7-10 days after infection with symptoms - bloody diarrhea, fever, vomiting.
If left untreated, the consequences of amoebiasis develop - dehydration, exhaustion, weakness, internal bleeding, liver abscess. Infection most commonly occurs via the oral-fecal route. Carriers of amoeba cysts can be insects - flies, gadflies. During the diagnosis, there are tissue forms of protozoa in the feces. Treatment of amoebiasis is inpatient, with the use of antibiotics.
Malarial Plasmodium
Representative of the simplest sporozoans, the cause of a dangerous disease - malaria. The human body serves as an incubator in which the life cycle of the parasite takes place. Characteristics of parasitism:
- Plasmodium sporozoite infection occurs when bitten by a malaria mosquito;
- sporozoites enter the bloodstream with the saliva of an infected insect;
- sporozoites settle in the liver, penetrate its cells (hepatocytes);
- here merozoites are formed by mitotic replication;
- when hepatocytes are destroyed, merozoites penetrate erythrocytes;
- from merozoites as a result of the sexual cycle gametocytes are formed;
- the mosquito becomes infected with gametocytes when it is bitten by an infected person;
- in the body of mosquitoes gametocytes pass into oocysts and then into sporozoites;
- the mosquito infects a healthy person and the cycle repeats itself.
The destruction of erythrocytes and the release of gametocytes into the bloodstream in humans is accompanied by attacks of fever, vomiting, anemia, convulsions and joint pain. In severe cases, the risk of death increases. Malaria often takes on a recurrent character with phases of exacerbation and rest. Different protozoa cause tropical malaria, three-day and four-day. The main therapeutic and diagnostic agent is quinine - natural from cinchon or artificially synthesized.
Infusoria balantidia coli
This causative agent of balantidia (or infusional dysentery) lives in the large intestine, causing bleeding ulcers on its walls. The infection of protozoa comes from domestic animals, it is mostly a carrier of pigs. Characteristics of anatomy and parasitism:
- the body of the balantidia is ovoid with a dense, strong shell (pellicle);
- there are many cilia on the surface that serve to move;
- the sexual form of the parasite is necessary for reproduction by simple fission;
- asexual form (cysts) enters the environment with feces;
- The route of cyst infection in humans is oral-fecal.
The movement of protozoa into the intestine in humans is accompanied by headache, vomiting, and dyspepsia. The acute stage of balantidiasis is manifested by a febrile condition, signs of severe intoxication, loose stools with blood clots. In the absence of timely treatment, a fatal outcome is possible.
Toxoplasma gondii
Crescent-shaped microscopic protozoa of the order Coccidia are widespread in the environment. They are the cause of the disease - toxoplasmosis. In healthy people, ingested pests destroy immune cells. Characteristics of diseases caused by protozoan parasites in humans:
- toxoplasmosis is often asymptomatic, and immunity develops after recovery;
- parasite affects the organs of sight, reproductive, nervous, lymphatic system, liver, spleen;
- during pregnancy, toxoplasmosis causes severe congenital pathologies in the fetus or its death;
- acute form continues with convulsions, paralysis, liver hypertrophy, heart problems;
- in the chronic course, heart dysfunctions and damage to the organs of vision are possible.
The main hosts of protozoa are cats. Oocyst colonies form huge colonies of toxoplasma in their body. People are inter-hosts, they become infected through food, contact-house or oral-fecal infection.