The term “protozoal” is derived from the Greek words “protos,” that is, “first,” and “zoon,” that is, “animal.” This is the name of the kingdom of the simplest living organisms, which appeared on our planet one of the first. Despite the elementary nature of their structure and vital functions, a large group of these tiny creatures causes deadly protozoal infections in humans and animals. With some microorganisms, a person becomes infected through his own fault, as he does not observe cleanliness. But there are also such protozoa that have learned to penetrate the victim with the help of other animals - mosquitoes, flies, ticks and others, which are not always possible to protect themselves from bites. We offer detailed information on what the symptoms of infection are, methods of treatment and prevention.
Morphological portrait of protozoa
In total there are hundreds of species of protozoa on Earth. Protozoal infections are caused only by those that have adapted to the parasitic lifestyle. Protozoa live in all parts of the world, and everywhere: in soil, in water, in air, in other living forms. All of them consist only of a single cell, in which all vital elements are concentrated.
Most protozoa can move, are predators, and reproduce not only by simple division, but also sexually. Parasitic species in the process of evolution have developed and secured various ways to penetrate their prey. So, those of them that parasitize in the digestive tract, use mainly the nutritional path. At the same time, adults or their cysts leave their host in the environment (with feces, urine, less often saliva), where they live for a certain time until they reach the new owner via the contact-oral route (using dirty hands and food). Protozoa that are parasitic in the blood travel from victim to victim with the help of blood-sucking insects. There are also parasites who have chosen for themselves the sexual route of penetration into a new host.
Diseases caused by protozoa
Open and studied to date, causative agents of protozoal infections cause the following diseases:
- amoebiasis;
- malaria;
Giardiasis
- toxoplasmosis;
- leishmaniasis;
- sleeping sickness;
- babesiosis;
- Chagas disease;
- trichomoniasis;
- balantidiasis;
- sarcocystosis (mainly affects cattle);
- isosporosis;
- cryptosporidiosis.
Let us consider in more detail the most common of them and begin with intestinal, having a similar etiology and pathology.
Amoebiasis
This disease is also called amoebic dysentery. Some types of amoeba, capable of living only in humans, cause it. Protozoal infections of this type can only be transmitted from an already infected person. Amoebic dysentery is second in the list of deadly diseases. Most often it is observed where there is a hot climate and complete unsanitary conditions. Cysts of parasites with feces go outside (on the ground, into the water), where they can live for several weeks. They penetrate a new victim with food, water. Flies, cockroaches, and other human "companions" can transmit the infection to products. Once in the intestines, cysts destroy their membranes and invade the intestinal tissue, causing ulceration and even necrosis. Sometimes with blood they can be introduced into other organs, such as the liver. The patient has symptoms about a week after the invasion:
- stomach ache;
- temperature;
- weakness;
- diarrhea (sometimes with blood and mucus).
Without proper treatment, the disease can turn into a chronic form, which leads to perforation of the intestinal walls, peritonitis and other complications.
Diagnosis is by colonoscopy, ultrasound, PCR. For treatment, “Metronidazole" or "Tinidazole" preparations are used.
Prevention of protozoal intestinal infections, including amoebic dysentery, consists mainly in maintaining cleanliness and hygiene. It is mandatory to:
- boil water from open reservoirs before use;
- observe the hygiene of the hands and body;
- wash fruits, berries, vegetables intended for food;
- destroy insects - carriers of infection.
Also, for the purpose of prevention, all workers employed in the food industry are examined, and a complete disinfection is carried out in the center where the disease is detected.
Giardiasis
Protozoal infections of the intestinal class include this disease. Its causative agent is Giardia. Unlike amoebas, they can be transmitted to humans from dogs, cats, rodents, in which they also parasitize. The causes of infection, as in the case of amoebiasis, are the lack of sanitation and hygiene. Giardia parasitize only in the small intestine, and moving to the thick, they form cysts, which are excreted with feces. In the external environment they live more than a month. All protozoal intestinal infections have a number of common symptoms - abdominal pain, lethargy, fatigue, diarrhea.
With giardiasis, nausea, allergic dermatitis, biliary tract dysfunction are added to them, and diarrhea can be temporarily replaced by constipation. There is usually no blood in the stool, but mucus may be present.
Diagnosis of giardiasis is carried out using fecal studies for the presence of cysts in it.
The treatment is carried out in stages:
1. Elimination of toxicosis and restoration of bowel function.
2. With the help of drugs "Trichopolum", "Tiberal" and the like, parasites are destroyed.
3. Strengthening immunity, diet therapy, taking vitamins and prebiotics.
Prevention of giardiasis consists in maintaining cleanliness, personal hygiene, as well as in the examination of persons, especially children, for the carriage of giardia.
Cryptosporidiosis
There are protozoan infections that are not so familiar to a wide circle, but also very dangerous. One of them is cryptosporidiosis, caused by the protozoa of the Cryptosporididae family and capable of leading to death. They are infected by the oral-contact route, using untreated water from rivers, ponds, even water pipes, unwashed fruits or vegetables, as well as during anal sex. The course of cryptosporidiosis is mainly acute, the incubation period lasts up to one and a half weeks, less often up to a month, and the main symptom is severe diarrhea. Also in patients observed:
- nausea before vomiting;
fever;
- pain in the peritoneum;
- cramps;
- symptoms of dehydration.
In people with high immunity, the disease can proceed without symptoms, but they are carriers of parasites.
Cryptosporidiosis leads to pancreatitis, cholecystitis, cholangitis, affects the lungs, stomach and pancreas. An ideal tool that completely helps with this infection has not yet been developed.
Prevention is the sanitization of food, water, pasteurization of milk, and thorough personal hygiene.
Rarely protozoal intestinal infections
These include balantidiasis, the culprit of which is the infusoria Balantidium coli, and isosporosis caused by protozoa of the genus Isospora. Ciliates of Balantidium coli live in the digestive tract of pigs, in which the disease symptoms may be absent. They enter the human body with raw meat or in a way that is classic for all intestinal infections. The main symptoms of the acute form of balantidiasis are diarrhea, abdominal pain, fever, signs of intoxication. With the transition of the disease into a chronic form, the manifestation of symptoms weakens or they completely disappear, but the person becomes a carrier of the pathogen.
The simplest isospores in nature are very widespread. They enter the human body through alimentary routes. The incubation period stretches for a week and a half, after which the disease begins acutely. The patient develops fever, vomiting, diarrhea, severe abdominal pain. In HIV-infected patients, isosporosis can cause death. The treatment is carried out with antimicrobial agents: Fansidar, Metronidazole and others.
Malaria
There are severe protozoal infections, the treatment of which does not always end successfully. One such disease is malaria. Every year it affects up to 300 million people, of which about 750 thousand die. It is transmitted by malaria mosquitoes at the time they suck blood.
Malaria is observed all over the globe, except for regions with a very cold climate, since low temperatures are harmful to mosquitoes. Malarial plasmodia with blood are introduced into the liver, where they begin to multiply with fantastic activity by simple division. One parasite can produce 40 thousand new living organisms! They are called merozoites. This process takes place for the patient without symptoms. After about a month and a half, young merozoites leave the liver and enter the bloodstream. Here they attach to red blood cells and begin pathogenic activity. In this case, there are:
fever
- intolerable headaches;
- chills;
vomiting
- convulsions;
- sometimes loss of consciousness;
- anemia;
- ischemia;
- excretion of hemoglobin in the urine.
For decades, malaria has been treated with quinine. Now new medicines have been developed, such as Artezunat, Amodiachin, Kotrifazit, Meflohin and others. Some of them are used not only for treatment, but also for prevention. Unfortunately, there are no vaccines against malaria.
Toxoplasmosis
This is a very dangerous protozoal infection, especially for infants. Its simplest Toxoplasma gondii cause. The source of infection are very many (over 180 species) domestic and wild animals. According to WHO, half of humanity is infected with toxoplasmosis. The causes of infection are:
- the use of not processed meat, eggs, milk;
- contact with sick pets;
- dirty hands (after working with infected animals);
- intrauterine transmission;
- blood transfusion and / or organ transplantation;
- for children, parents are carriers of microorganisms.
Symptoms of the disease may be as follows:
- temperature;
- headache;
vomiting
- paralysis;
- damage to many organs and systems.
Toxoplasmosis occurs in two forms - acute and chronic and can be either congenital or acquired.
The prognosis for infants is extremely unfavorable; enhanced therapy is being carried out to save their lives. Everyone else does not need treatment, since the acute form of toxoplasmosis goes away on its own.
Babesiosis
This protozoal infection affects humans and animals. The carrier of the pathogen are ticks. Symptoms
- heat;
fever;
- enlarged liver and spleen.
In animals, there is a sharp deterioration, diarrhea, constipation, rapid breathing, bloody urine, milk becomes bitter in cows, and pregnancy terminates in sheep. Mortality among animals from babesiosis is up to 80%.
In humans, the disease can occur in mild or severe forms. The treatment is carried out with the preparations "Berenil", "Albargin", "Acaprine" and others.
Prevention of protozoan infections transmitted by blood-sucking insects consists mainly in their destruction, as well as in vaccination.
Exotic diseases
In addition to widespread, there are protozoal infections diagnosed only in certain regions. You can get sick with them when you go there on vacation or at work. For example, in countries in tropical Africa, the so-called sleeping sickness, which rewards people with the tsetse fly, is common. After her bite, the first symptoms appear after 1-3 weeks. It can be headaches and joint pains, fever, itching. After a couple of months, a person has numbness, confusion, loss of orientation in movements. The treatment of sleeping sickness is only medication.
In Latin America, there is another misfortune called Chagas disease. They bring it to people kissing bugs that are carriers of the simplest microorganisms of the species Trypanosoma cruzi. The symptomatology of the disease is wide, since inflammatory processes occur in many organs: in the heart, liver, muscles, brain and spinal cord, and degenerative changes in organs in this case are irreversible. The disease proceeds in two stages. The first is characterized by pain in the abdomen, chest, muscles of the whole body, heart failure, fever, shortness of breath. The second for the majority of infected people passes without symptoms, only some have symptoms of damage to the nervous, digestive and cardiovascular systems.
Prevention of protozoal and viral infections
Infection with protozoa is in many ways similar to infection with viruses. So, almost all types of fevers (dengue, yellow, West Nile, Karelian) cause various viruses, and mosquitoes carry them from healthy to sick. Another common carrier of protozoa and viruses is the tick, which bites can cause encephalitis. Well, the rotavirus known to many of us enters the body of the victim if hygiene rules are not followed.
Since the ways of infection with the simplest parasites and viruses are not much different, the prevention of protozoal and viral infections should be very similar. Ogulov A.T., in collaboration with Eshtokina G.M. and Abdusalamova F.M. published a book that describes many infectious, fungal, helminth infections. It also tells how to treat them and how to protect yourself from them. The main thing that everyone and everyone needs to observe is sanitation and hygiene. These postulates become a barrier to so many human parasites. Preventive measures against infections transmitted by insects are their destruction and the elimination of habitats. Well, vaccination is the best prevention of infections against which the body produces immunity.