The simplest parasite is an organism that has adapted to invade and live in the cells and tissues of other organisms. The simplest parasites cannot live alone in an open environment like other protozoa, but must invade the body of another organism to receive protection and nourishment.
The simplest pests and their varieties
The simplest organisms are eukaryotic systems that exist as structurally and functionally independent single cells (including those species that are gregarious or colony-forming). Protozoa develop relatively complex subcellular tracts (membranes and organelles) that allow them to survive in harsh environmental conditions. Most protozoa are microscopic organisms, and only a few of them grow large enough to be visible to the naked eye. Like single-celled eukaryotes, they move to survive, feed and reproduce.
There are some of the simpler parasites that cause problems. They are present in our food, soil and water and can make us seriously ill if they get inside.
Each different parasitic protozoan can cause different diseases in our bodies. Some of them can cause severe diseases of the respiratory tract (passage of air from the nose to the lungs) and of the central nervous system (brain, cranial nerves and spinal cord), while others live in the intestine, causing symptoms such as diarrhea and are not fatal. .
There are four types of protozoan parasites, which are classified based on how they move:
- sarcodes are a group of amoebas that move using pseudopods and contractions that change the shape of their cells;
- mastigophores move with the help of flagella;
- siliophores use eyelashes;
- the sporozoa are immobile when they are in their mature phase.
Life cycles of protozoan parasites
Most protozoa have enormous reproductive potential because they have a short generation time, undergo rapid sequential development, and produce large numbers of offspring asexually or sexually. These features are responsible for many of the simpler infections, rapidly causing acute symptoms of the disease.
The developmental stages of protozoal parasites occurring within the host usually consist of feeding trophozoites and can be found intracellularly (within the host's cells) or extracellularly (in hollow organs, body fluids or internodes between cells). Although trophozoites are ideal for their parasitic mode of existence, they are not very resistant to external environmental conditions and do not survive long outside their hosts. To move from host to host, protozoan parasites use one of four main modes of transmission: direct, fecal-oral, transmissible, and predator-to-prey.
Ways of transmission of protozoan parasites to humans
- Direct transmission of parasites through intimate contact with the body - sexually (for example, Trichomonas talked about fungi, which cause trichomoniasis in humans).
- Fecal-oral transmission of ecologically stable stages of cysts - parasites pass in the feces of one host and are transmitted with food or water to another (e. g. , Entamoeba histolytica, Giardia duodenalis, and Balantidium coli are all forms of fecal cysts that lead to amoebic dysentery, giardiasis and balantidiosis).
- Transmission occurs when parasites are ingested by bloodsucking arthropods (insects or arachnids) and transmitted to new hosts via a bite (e. g. Trypanosoma brucei, transmitted by tsetse flies and causing sleeping sickness, and Plasmodium spp. Haemosporidia , transmitted by mosquitoes and causing malaria).
- Predator-to-prey transmission occurs when the simplest parasite gets stuck in the victim's tissues (for example, a cow, a goat, a pig) and is eaten by a predator (in our case, a person).
The simplest human parasites and the diseases they cause
Acanthamoeba. This parasite infects a person's eyes or brain and causes exogenous amoebiasis. It can live in any region of the world. People can get it when they clean their contact lenses with tap water.
Babesia. It infects red blood cells and causes a disease called babesiosis. Different types of parasites live in different parts of the world. It is transmitted by ticks when bitten.
Balantidium (Balantidium coli). It lives in the intestinal mucosa, causes ciliated dysentery, also called balantidiosis.
Blastocystis (Blastocystis). This parasite infects the host's intestine. It enters humans through ingested food contaminated with human or animal feces. The disease caused by this parasite is called blastocytosis.
Cryptosporidium (Cryptosporidium). It lives in the human intestine. Distributed all over the world. It enters the human body through ingested food contaminated with human or animal feces.
Amoeba dysentery (Entamoeba histolytica). This simpler parasite causes intestinal amoebiasis. Most often it is found in areas with high population density, poor sanitation and tropical regions. It is transmitted by the fecal-oral route.
Giardia lamblia "is not English. It lives in the lumen of the small intestine. If people consume food or water contaminated with feces, dormant Giardia cysts can infect the body, causing intestinal giardiasis. It is particularly dangerous for children and requires compulsory adherence to the treatment regime.
Isospore (Isospora belli). It affects the epithelial cells of the small intestine. Distributed all over the world. It is transmitted by the fecal-oral route and is the causative agent of isosporia.
Leishmania. It parasites the skin and internal organs of a person. It exists all over the world in various forms. Transmitted by certain types of mosquitoes when bitten.
Negleria (Naegleria fowleri). It causes primary amoebic meningoencephalitis, as it lives in the human brain. Infection occurs through contaminated soil, swimming pools and contaminated water.
Plasmodium (Plasmodium falciparum, P. vivax, P. ovale, P. malariae). Parasites enter red blood cells and cause malaria. They exist in tropical regions where the anopheles, also known as the anopheles mosquito, is carried.
Rhinosporidium seeberi. It multiplies in the nose and nasopharynx, growing there in the form of spores. It exists in India and Sri Lanka. People who swim in public waters can become infected with the parasite when the nasal mucosa comes in contact with contaminated material.
Toxoplasma (Toxoplasma gondii). It affects the liver, heart, eyes and brain. A parasite spread all over the world. People can become infected after eating raw or undercooked pork, lamb, goat, or milk. It can also exist in contaminated food or soil due to cat feces. The disease caused by this parasite is called toxoplasmosis or parasitic pneumonia.
Trichomonas (Trichomonas vaginalis). Infects the female urogenital tract. Symptoms differ in men and women. It is the causative agent of trichomoniasis, a sexually transmitted infection.
Trypanosomes (Trypanosoma brucei, Trypanosoma cruzi). The first type of parasite affects the central nervous system, blood and lymph. It is transmitted by the tsetse fly and causes the so-called sleeping sickness. The second parasite causes Chagas disease by affecting the blood, muscles, nerves, heart, esophagus, and intestines. Also transmitted by insect bites.
How to treat infections caused by protozoan parasites in humans?
The treatment plan for a protozoan parasite infection will depend on the specific diagnosis. Typically, the doctor will prescribe drugs, for example, to treat trichomoniasis, giardiasis, or cryptosporidiosis. Usually, medications are not prescribed for toxoplasmosis unless there are conditions for it in the form of pregnancy, some other illness, or a severe and prolonged infection.
The doctor may also recommend other treatments to relieve symptoms. For example, many parasitic infections can cause diarrhea, which often leads to dehydration. Therefore, when treating an infection caused by protozoan parasites, it is usually recommended to drink plenty of fluids to replenish the loss in the body.
How can parasites of protozoa be prevented?
There are several steps you can take to reduce the risk of getting a parasitic infection:
- practicing safe sex using condoms;
- wash your hands regularly, especially after handling raw food or feces;
- Cook the food at the recommended core temperature.
- drink clean water, including bottled water, when traveling;
- avoid swallowing water from lakes, streams or ponds;
- avoid litter and feces during pregnancy.
If you suspect you have a parasitic infection, make an appointment with your doctor. They can help diagnose the cause of the symptoms and recommend a treatment plan. The sooner you start treatment, the sooner you can help stop the infection from spreading to others.