Protozoal parasites in humans are the causative agents of protozoal infections (or protozoa). These diseases are contagious and threaten serious complications and consequences. Therefore, protozoosis requires timely diagnosis, accurate identification of the pathogen and adequate treatment.
What are parasitic protozoa
This is a group of single-celled microorganisms that are unable to independently generate nutrients. In the process of life, they use other creatures, causing them serious diseases. The most common human protozoan parasites are listed below:
- flagella - giardia, leishmania, trichomonas, trypanosoma;
- sarcodal - dysenteric amoeba;
- ciliates - borsari, balantidia;
- sporozoa - malarial plasmodium, coccidia, pyroplasmas.
Trypanosome
The simplest parasite whose life cycle takes place in the body of ungulates (antelopes) or an infected person. Carriers are tsetse flies that, when bitten by a person, inject saliva with protozoa into his skin.
On a note!
For the development of the disease (African trypanosomiasis or sleeping sickness) the introduction of about 400 trypanosomes is required. With one bite of a tsetse fly, up to half a million individuals of the parasite fall.
Features of parasitism and disease:
- trypanosomes initially circulate in the bloodstream of an infected person, causing trypanids on the skin (swelling of the face, eyelids), fever with a temperature of up to 40 ° C, swelling of the lymph nodes;
- then the unicellular parasites migrate into the cerebrospinal fluid, causing drowsiness, iridocyclitis, chronic fatigue, lethargy, speech disorders, coordination;
- the advanced form of trypanosomiasis is characterized by seizures of the limbs, seizures, nervous and physical exhaustion, respiratory paralysis, coma and death.
For the diagnosis of trypanosomiasis, the Romanovsky-Giemsa test, immunofluorescence reaction, enzyme immunoassay (ELISA), puncture of the lymph nodes are used. Confirmation of the diagnosis is often done by introducing the blood of a sick person into laboratory pigs. Treatment of sleeping sickness involves taking special medications. In the absence of therapy with a high degree of probability, a fatal outcome of the patient 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 sucker, often lodged in the ducts of the liver, gallbladder and other internal organs.
On a note!
Protozoal infection occurs with food, water, in unsanitary 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 waste water). Diagnosis of protozoa is carried out by microscopy of cysts and adults in the feces, blood, detection of antibodies in the ELISA study.
Leishmania
These flagellate protozoa cause leishmaniasis, a common disease in tropical and subtropical countries. Infection occurs transmissible - when bitten with the saliva of blood-sucking insects, animals (dogs, ground squirrels). Mosquitoes, mosquitoes, gadflies, ticks can be carriers. There are two types of leishmaniasis in humans:
- cutaneous and mucocutaneous form (pendinskaya ulcer) - leishmania lives and multiplies in human skin, causing inflammation, swelling, ulceration, trophic ulcers, damage to the respiratory tract;
- visceral form - leishmania is deposited in the internal organs (spleen, liver, lungs, heart).
A characteristic sign of cutaneous leishmaniasis is the formation of brownish nodules (leishmaniasis) at the site of the insect bites. Then they are replaced by hard-to-heal round ulcers with purulent exudate. The disease continues for 1-2 years, leaving scars on the skin. In the visceral form, leishmaniasis causes dysfunction of the adrenal glands, kidneys, liver and spleen. When diagnosing leishmania, they are found in the bone marrow, lymph nodes, skin scrapings, and blood.
On a note!
Treatment of leishmaniasis involves quarantine measures, patient isolation, and medications.
Trichomonas
These are the simplest parasites of the human internal environment, which are transmitted sexually, through home contact or as a result of a mother-to-child birth infection. There are oral, intestinal and urogenital varieties of Trichomonas. Protozoa are the causative agents of trichomoniasis / trichomoniasis. Urogenital trichomoniasis of the genitourinary system is widespread. The chronic form of the disease threatens impotence and persistent infertility. Characteristics of Trichomonas parasitism:
- body size: up to 18 microns, they move quickly thanks to the mobile flagella;
- drug resistant, resulting in the chronic course of trichomoniasis;
- they quickly die in the environment, in the air, under the direct rays of the sun;
- long stay on wet wipes, sponges, towels, soap dishes;
- frequent infections during sexual intercourse of the vaginal, oral-vaginal type;
- Trichomonas contributes to the development of candidiasis, vulvitis, chlamydia, gonorrhea, cystitis.
Diagnosis of trichomoniasis includes the detection of Trichomonas in swabs from the genitals. Treatment involves the use of drugs, treatment with antiseptics. Therapy is performed in both partners to avoid relapse. Prevention of urogenital trichomoniasis includes measures 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 dysentery 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 often occurs via the fecal-oral route. Carriers of amoeba cysts can be insects: flies, gadflies. During diagnosis, tissue forms of protozoa are found in the stool. Treatment of amoebiasis is stationary, with the use of antibiotics.
Malarial plasmodium
Representative of the simplest sporozoa, the causative agent of a dangerous disease - malaria. The human body acts as an incubator in which the parasite's life cycle takes place. Characteristics of parasitism:
- plasmodium sporozoite infection occurs when bitten by a malarial mosquito;
- sporozoites enter the bloodstream with the saliva of an infected insect;
- sporozoites settle in the liver, penetrate its cells (hepatocytes);
- here the merozoites are formed by mitotic replication;
- when hepatocytes are destroyed, merozoites penetrate the erythrocytes;
- gametocytes are formed from merozoites following the sexual cycle;
- a mosquito becomes infected with gametocytes when bitten by an infected person;
- in the body of a mosquito the gametocytes pass into the oocysts and then into the sporozoites;
- a mosquito infects a healthy person and the cycle repeats itself.
The destruction of erythrocytes and the release of gametocytes into the bloodstream is accompanied in humans by bouts of fever, vomiting, anemia, convulsions and joint pain. In severe cases, the risk of death increases. Malaria often takes on a relapsing character with phases of exacerbation and rest. Several protozoa cause tropical, three-day and four-day malaria. The main therapeutic and diagnostic agent is quinine, natural from cinchona or artificially synthesized.
Infusoria balantidia coli
This causative agent of the disease balantidia (or infuser dysentery) lives in the large intestine, causing bleeding ulcers on its walls. Protozoal infection occurs from domestic animals, mainly the carrier is a pig. Features of anatomy and parasitism:
- the body of the balantidia is ovoid with a dense and robust shell (film);
- on the surface there are many cilia which serve for movement;
- the sexual form of the parasite is necessary for reproduction by simple fission;
- the asexual form (cyst) enters the environment with feces;
- The route of human infection with cysts is fecal-oral.
Resettlement of protozoa in the intestine is accompanied by headache, vomiting and dyspepsia in humans. The acute stage of balantidiasis is manifested by a feverish state, signs of severe intoxication, loose stools with blood clots. In the absence of timely treatment, a fatal outcome is possible.
Toxoplasma gondi
The microscopic crescent-shaped spore protozoa of the order Coccidia are widely distributed in the environment. They are the causative agents of the disease: toxoplasmosis. In healthy people, ingested parasites are destroyed by immune cells. Characteristics of the disease caused by protozoan parasites in humans:
- often toxoplasmosis is asymptomatic, immunity develops after recovery;
- the parasite affects the organs of vision, the reproductive, nervous, lymphatic systems, the liver, the spleen;
- during pregnancy, toxoplasmosis causes severe congenital pathologies in the fetus or its death;
- the acute form proceeds with convulsions, paralysis, liver hypertrophy, heart problems;
- in a chronic course, dysfunctions of the heart, damage to the visual organs are possible.
The main hosts of protozoa are felines. Huge colonies of Toxoplasma form from oocysts in their body. People are intermediate hosts, they are infected by food, contact-house or fecal-oral route.