The simplest parasite is an organism that is adapted to invading and living 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 get protection and food.
The simplest parasites and their varieties
The simplest organisms are eukaryotic systems that exist as structurally and functionally independent individual cells (including those that are social or form colonies). Protozoa develop relatively complex subcellular properties (membranes and organelles) that allow them to survive in harsh environmental conditions. Most protozoa are microscopic organisms, and only a few grow large enough to be visible to the naked eye. As unicellular eukaryotes, they move to survive, feed, and reproduce.
There are some of the simplest parasites that cause problems. They are present in our food, soil and water and can make us very ill if they ever enter us.
Each different protozoan parasite can cause different diseases in our bodies. Some of them can cause serious diseases of the respiratory tract (passage of air from the nose to the lungs) and the central nervous system (brain, cranial nerves and spinal cord), while others live in the intestines causing symptoms such as diarrhea and are not fatal.
There are four types of protozoan parasites, which are classified according to the mode of movement:
- sar codes are a group of amoebae that move by means of pseudopods and contractions that change the shape of their cells;
- mastigophores move with the help of flagella;
- siliophores use cilia;
- sporozoans are immobile when in the 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 characteristics are responsible for many of the simplest infections that quickly cause acute symptoms of the disease.
The developmental stages of protozoan parasites that occur within a host usually consist of trophozoite feeding and can be found intracellularly (within host 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 highly resistant to external environmental conditions and do not survive long outside the host. To migrate from host to host, protozoan parasites use one of four main modes of transmission: direct, fecal-oral, transmissible, and from predators to prey.
Ways of transmitting protozoan parasites to humans
- Direct transmission of parasites through intimate contact with the body - sexually (for example, trichomonads spoke fungi that cause trichomoniasis in humans).
- Fecal-oral transmission of ecologically stable cyst stages - parasites pass into the feces of one host and are transmitted by food or water to another (for example, Entamoeba histolytica, Giardia duodenalis and Balantidium coli are all forms of fecal cysts leading to amoeba dysentery, giardiasis and balantidiosis).
- Transmission occurs when parasites are introduced from blood-sucking arthropods (insects or arachnids) and the bite is transmitted to new hosts (for example, Trypanosoma brucei, transmitted by tse flies and causing sleeping sickness, and Plasmodium spp. Haemosporidia, transmitted by mosquitoes). ). and causes malaria).
- Transmission from predators to prey occurs when the simplest parasite gets stuck in the victim’s tissue (e. g. , cow, goat, 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. He can live in any part of the world. People can get it when cleaning 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, causing ciliary dysentery, also called balantidiosis.
Blastocystis (Blastocystis). This parasite infects the intestines of the host. It enters humans through ingested food contaminated with human or animal feces. The disease caused by this parasite is called blastocytosis.
Cryptosporidium. It lives in the intestines of man. Distributed worldwide. It enters the human body through ingested food contaminated with human or animal feces.
American dysentery (Entamoeba histolytica). This simplest parasite causes intestinal amoebiasis. They are most commonly found in areas with high population density, poor sanitation and tropical regions. It is transmitted by faecal-oral route.
Giardia lamblia. 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 especially dangerous for children and requires mandatory adherence to the treatment regimen.
Isospore (Isospora belli). It affects the epithelial cells of the small intestine. Distributed worldwide. It is transmitted by the faecal-oral route and is caused by isospores.
Leishmania. It parasitizes a person's skin and internal organs. It exists all over the world in various forms. They transmit some types of mosquitoes when bitten.
Negleria (Naegleria fowleri). It causes primary amoebic meningoencephalitis because 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 Anopheles, also known as Anopheles mosquito, is transmitted.
Rhinosporidium seeberi. It multiplies in the nose and nasopharynx, growing 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 is in contact with contaminated material.
Toxoplasma gondii. It affects the liver, heart, eyes and brain. A widespread parasite throughout the world. People can become infected after eating raw or undercooked pork, lamb, goat or milk. They 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 between men and women. It is the cause 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 fly agaric and causes the so-called sleeping sickness. Another parasite causes Chagas disease by affecting the blood, muscles, nerves, heart, esophagus and intestines. It is also transmitted by insect bites.
How to treat infections caused by protozoan parasites in humans?
The treatment plan for protozoan parasite infection will depend on the specific diagnosis. Usually your doctor will prescribe medication, for example, to treat trichomoniasis, giardiasis or cryptosporidiosis. Usually, medications for toxoplasmosis are not prescribed unless there are conditions for it in the form of pregnancy, some other illness, or a severe and long-lasting infection.
Your doctor may recommend other treatments to relieve your symptoms. For example, many parasitic infections can cause diarrhea, which often leads to dehydration. Therefore, in the treatment of infection caused by protozoan parasites, it is usually recommended to drink plenty of fluids to compensate for the loss in the body.
How can protozoan parasites be prevented?
There are several steps you can take to reduce your risk of contracting a parasitic infection:
- practice safe sex using a condom;
- wash your hands regularly, especially after handling raw food or feces;
- Cook food at the recommended core temperature.
- drink clean water, including bottled water, while traveling;
- avoid swallowing water from lakes, streams or ponds;
- Avoid litter and feces of cats during pregnancy.
If you suspect you have a parasitic infection, make an appointment with your doctor. They can help diagnose the cause of your symptoms and recommend a treatment plan. The sooner you start treatment, the sooner you can help stop the spread of the infection to others.