The simplest parasite is an organism adapted to invade and live in the cells and tissues of other organisms. The simplest parasites cannot live in an open environment on their own like other protozoa, but must invade the body of another organism in order to receive protection and nourishment.
The simplest parasites and their varieties
The simplest organisms are eukaryotic systems that exist as individual structurally and functionally independent cells (including those species that are clustered or colonized). Protozoa develop relatively complex subcellular traits (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 sick if they ever get inside us.
Every different protozoan parasite can cause different diseases in our body. 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, andare not deadly.
There are four types of protozoan parasites, which are classified according to the way they move:
- sarcoids are a group of amoebas that move using pseudopods and contractures that change the shape of their cells;
- mastigophores move with the help of the flagella;
- siliophores use cilia;
- sporozoans are immobile when they are in their mature stage.
Life Cycles of Protozoan Parasites
Most protozoa have great reproductive potential because they have a short lifespan, undergo rapid sequential development, and produce large numbers of asexually or sexually offspring. These characteristics are responsible for many of the simplest infections, quickly causing acute symptoms of the disease.
The developmental stages of protozoan parasites that occur inside the host usually consist of trophozoite food and can be found intracellular (inside the host cells) or extracellular (in empty 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 major modes of transmission: direct, fecal-oral, transmissible, and from predator to prey.
Ways of transmitting protozoan parasites to humans
- Direct transmission of parasites through intimate contact with the body - sexually (for example, Trichomonas spoke fungi, which cause trichomoniasis in humans).
- Fecal-oral transmission of ecologically viable cyst phases - 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 that lead to amoebicdysentery, giardiasis and balantidiosis).
- Transmission occurs when parasites are swallowed by arthropods that suck blood (insects or arachnids) and pass on to young animals by a single bite (e. g. Trypanosoma brucei, transmitted by csetse flies and causing sleeping sickness, and Plasmodium spp. Hemosporidia, transmittedfrom mosquitoes and causing malaria).
- Transmission from predator to prey 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. He can live in any region 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. Transmitted by ticks when bitten.
Balantidium (Balantidium coli). Lives in the intestinal mucosa, causes ciliary dysentery, also called balantidiosis.
Blastocystis (Blastocystis). This parasite infects the host intestines. It enters humans through ingested food contaminated with human or animal feces. The disease caused by this parasite is called blastocytosis.
Cryptosporidium (Cryptosporidium). Lives in the human gut. Distributed worldwide. It enters the human body through ingested food contaminated with human or animal feces.
Amoeba dysentery (Entamoeba histolytica). This simple parasite causes intestinal amoebiasis. Most often found in areas with high population density, poor sanitation and tropical regions. Transmitted by the fecal-oral route.
Giardia lamblia. 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). Affects the epithelial cells of the small intestine. Distributed worldwide. It is transmitted by the fecal-oral route and is the causative agent of isosporia.
Leishmania. Parasitizes a person's skin and internal organs. It exists all over the world in various forms. Transmitted by some species of mosquitoes when bitten.
Negleria (Naegleria fowleri). 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). The parasites enter the red blood cells and cause malaria. They exist in the tropical regions where Anopheles mosquitoes are known, also known as Anopheles mosquitoes.
Rhinosporidium seeberi. It multiplies in the nose and nasopharynx, growing there in the form of spores. 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. Affects the liver, heart, eyes and brain. A parasite spread all over the world. People can become infected after eating pork, lamb, goat or raw milk. It can also exist in food or contaminated soil due to cat feces. The disease caused by this parasite is called toxoplasmosis, or parasitic pneumonia.
Trichomonas (Trichomonas vaginalis). It infects the female urogenital tract. Symptoms vary in men and women. The agent is the causative agent of trichomoniasis, a sexually transmitted infection.
Trypanosomet (Trypanosoma brucei, Trypanosoma cruzi). The first type of parasite affects the central nervous system, blood and lymph. It is transmitted by tsetse flies and causes so-called sleep disorders. 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, your doctor will prescribe medication, 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 disease or a severe and prolonged infection.
Your doctor may also recommend other treatments to help 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 protozoan parasites be prevented?
There are some steps you can take to reduce the risk of contracting a parasitic infection:
- practice safe sex using a condom;
- wash your hands regularly, especially after handling raw foods or feces;
- Cook food at the recommended base temperature.
- drink clean water, including bottled water, when traveling;
- avoid swallowing water from lakes, streams or ponds;
- avoid cat 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 your symptoms and recommend a treatment plan. The sooner you start treatment, the sooner you can help stop the infection from spreading to others.