The simplest parasites are organisms that are adapted to invade and live in the cells and tissues of other organisms. The simplest parasites cannot live in their own open environment like other protozoa, but must invade the bodies of other organisms for protection and food.
The simplest parasites and their types
The simplest organisms are eukaryotic systems that exist as structurally and functionally independent individual cells (including species that like plants or form colonies). Protozoa develop relatively complex subcellular properties (membranes and organelles) that allow them to survive harsh environmental conditions. A large number of protozoa are microscopic organisms, and only a small number 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 found in our food, soil and water and can make us very sick if they get into us.
Each different protozoan parasite can cause different diseases in our body. Some of them can cause serious diseases of the respiratory tract (airways from the nose to the lungs) and central nervous system (brain, cranial nerves and spinal cord), while others live in the intestines, causing symptoms such as diarrhea, and not fatal.
There are four types of protozoan parasites, classified according to the way they move:
- sarcodes are a group of amoebae that move using pseudopods and contractions that change the shape of their cells;
- mastigophores move with the help of flagella;
- siliophores using cilia;
- sporozoans do not move when they are in the mature stage.
Life Cycle of Protozoan Parasites
A large number of protozoa have enormous reproductive potential because they have a short generation time, undergo rapid sequential development, and produce a large number of offspring asexually or sexually. These features are responsible for many of the mildest infections, quickly causing symptoms of acute illness.
The stage of development of protozoan parasites that occur in the host usually consists of feeding trophozoites and can be found intracellularly (in the host cell) or extracellularly (in hollow organs, body fluids, or intercellular internodes). Although trophozoites are well suited for their mode of parasitic existence, they are not resistant to external environmental conditions and do not last long outside their homes. To migrate from host to host, protozoan parasites use one of four main methods of transmission: direct, fecal-oral, contagious, and from predator to prey.
Ways of transmission of protozoan parasites to humans
- The spread of parasites is directly through intimate contact with the body - sexually (for example, Trichomonas speaks fungus, which causes trichomoniasis in humans).
- Ecologically stable fecal -oral spread of cysts - parasites pass the feces of one host and spread 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).
- Infection occurs when parasites are ingested by blood -sucking arthropods (insects or arachnids) and spread to new hosts by bites (e. g. , Trypanosoma brucei, transmitted by tsetse flies and causing sleep disorders, and Plasmodium spp. Hemosporidia, transmitted by mosquitoes and causing malaria).
- Transmission from predator to prey occurs when the parasite is most easily trapped in the victim’s tissues (e. g. , a cow, goat, pig), and it is eaten by the predator (in our case, a person).
The simplest human parasites and the diseases they cause
Acanthamoeba. These parasites infect a person’s eyes or brain and cause exogenous amoebiasis. He can live anywhere in the world. People can get it while 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 spread by fleas when bitten.
Balantidium (Balantidium coli). Living in the intestinal mucosa, it causes ciliated dysentery, also called balantidiosis.
Blastocystis (Blastocystis). This parasite infects the intestines of the host. This enters humans through digested food contaminated with human or animal feces. The disease caused by this parasite is called blastocytosis.
Cryptosporidium (Cryptosporidium). Live in the human gut. Distributed worldwide. It enters the human body through contaminated food contaminated with human or animal feces.
Dysentery amoeba (Entamoeba histolytica). This simplest parasite causes intestinal amebiasis. Often found in areas with high population densities, poor sanitation and tropical regions. It is spread through the fecal-oral route.
Giardia lamblia. Stay in the lumen of the small intestine. If people consume food or water contaminated with feces, inactive Giardia cysts can infect the body, causing intestinal giardiasis. It is very dangerous for children and requires adherence to a treatment regimen.
Isospore (Isospora belli). Affects small intestinal epithelial cells. Distributed worldwide. It is spread through the fecal-oral route and is the causative agent of isosporia.
Leishmania. Paralyzes a person's skin and internal organs. It exists all over the world in various forms. Contagious by some types 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). Parasites enter red blood cells and cause malaria. They are in the tropics where Anopheles, also known as anopheles mosquitoes, are carried.
Rhinosporidium seeberi. It reproduces 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 parasites when the nasal mucosa comes in contact with contaminated material.
Toxoplasma (Toxoplasma gondii). Affects the liver, heart, eyes and brain. Parasites are widespread throughout the world. People can become infected after eating pork, lamb, goat, or raw or undercooked milk. It may also be present in food or soil contaminated with cat feces. The disease caused by this parasite is called toxoplasmosis, or parasitic pneumonia.
Trichomonas (Trichomonas vaginalis). It 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 spread by tsetse fly and causes a so -called sleeping sickness. The second parasite causes Chagas disease by affecting the blood, muscles, nerves, heart, esophagus, and intestines. Also spread by insect bites.
How to treat infections caused by protozoan parasites in humans?
The treatment plan for protozoan parasitic infections depends on the specific diagnosis. Usually, your doctor will prescribe medications, for example, to treat trichomoniasis, giardiasis, or cryptosporidiosis. Usually, medications are not prescribed for toxoplasmosis unless there is a condition for this in the form of pregnancy, other illness, or severe and prolonged infection.
Doctors may also recommend other treatments to relieve symptoms. For example, many parasitic infections can cause diarrhea, which often leads to dehydration. Therefore, when treating infections caused by protozoan parasites, it is usually recommended to drink plenty of fluids to supplement body loss.
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 condoms;
- wash your hands frequently, especially after handling raw food or feces;
- Cook food to the recommended core temperature.
- drink clean water, including bottled water, while you are traveling;
- avoid swallowing water from lakes, rivers or ponds;
- avoid litter and cat 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 spread of the infection to others.