Protozoa may be found in almost every environment. They may survive in the environment as free-living creatures, commonly in soil, water, or moss. They can also be resting cysts, allowing them to stay dry periods. Furthermore, certain protozoa are parasitic. Others exist in symbiosis with other organisms, dependent on each other to survive. Protozoa is derived from the Greek words protos, which means “first,” and zoia, which means “animal.” In the 1800s, it was initially coined. Before that, the organelles that constituted tiny protozoa could not be adequately recognised.
Acanthamoeba species are soil and water-dwelling free-living amoebae. Cyst stages can be carried in the air. Acanthamoeba species have been linked to life-threatening corneal ulcers in people who wear contact lenses. Contaminated lens-cleaning solutions most likely spread the parasites. Amoebas of the genus Naegleria, which live in freshwater bodies, are responsible for nearly all instances of primary amoebic meningoencephalitis, which is typically deadly. Water sprayed over the upper nasal passage while swimming or diving is assumed to be the source of the amoebas’ entry into the body. Based on laboratory investigations of Acanthamoeba infections in cell cultures and animals, human conditions of this sort might have been anticipated before they were discovered and published.
Classification
The Society of Proto-zoologists established a taxonomy classification, dividing Protozoa into six phyla in 1985. The Sarcomastigophora and Apicomplexa phyla contain the most significant organisms that cause human illness. The morphology revealed by optical, electron, and scanning microscopy provides the basis for this method. Dientamoeba fragilis, for example, was formerly classified as an amoeba and put in the Entamoebidae family. However, interior features shown by electron microscopy indicate that it belongs to the flagellate protozoa order Trichomonadida. Based on factors such as geographic distribution and clinical signs, organisms that seem similar under the microscope have been given alternative species names in some cases.
Characteristics of Protozoa
Size and shape: Protozoa come in various sizes and shapes, ranging from microbial (1 m) to big enough to be visible with the naked eye. A thin plasma membrane surrounds each cell. The exterior surface of certain species has a hard shell. Pellicle, which may be flexible or stiff and gives organisms a distinct form and aids in motility, supports the cell in some protozoans, particularly ciliates.
Nutrition: Protozoa are heterotrophic and holozoic in their diet. Phagocytosis is the process through which they consume their food. Several protozoan groups have a specialized structure called a cytostome. Amoeboids’ pseudopodia aid in the capture of prey. The food-laden water is driven down the gullet.
Reproduction: Asexual reproduction is the most common method of reproduction. Binary fission, longitudinal fission, transverse fission, and budding are all ways to multiply. Sexual reproduction is present in several animals. Conjugation, syngamy, or the generation of gametocytes are all methods of sexual reproduction.
Habitat: Protozoa live in an aquatic environment. They may be found in both freshwater and saltwater. Although some are anaerobic, they are primarily aerobic and located in the rumen or gut. Some of the species live in harsh conditions, such as hot springs. To cope with arid surroundings, some of them produce resting cysts.
Free-living Protozoa’s Life Cycle
The life cycle of this category is mainly composed of the organism’s development and expansion, followed by binary fission (or other forms of asexual reproduction). Sexual reproduction only happens in the free-living when conditions are adverse (unfavourable temperature, reduced food supplies, etc.). These parameters, however, often differ from one species to the next. DNA synthesis, chromosome replication, and cell expansion phase during the free-living protozoa’s growth and division cycle.
Diseases Caused by Protozoa
Protozoans are responsible for a variety of infectious illnesses, including:
- Malaria
- Giardia
- Toxoplasmosis
Diseases of the Digestive System Caused by Protozoa
Amoebic bacteria cause dysentery. Entamoeba histolytica is an amoeba that causes dysentery. The protozoan is found in nature as a cyst and is spread by contaminated food and water. The amoebas transform into trophozoites (feeding forms) and enter the gut lining in patients. Infected people can carry the infection for a long time. Metronidazole is the medicine of choice for treatment.
The symptom of protozoal infection ciliate Balantidium coli causes balantidiasis. The trophozoite form of this protozoan enters the body as a cyst and exits in the gut. Tissue invasion is possible, and blood and pus in the faeces are common. Symptoms usually linger for a long time. Patients become carriers of the virus. Metronidazole is a drug that may be used to treat various ailments.
The flagellate Giardia lamblia causes giardiasis, a symptom of protozoal infection illness. In contaminated food and drink, the organism is absorbed into the body as a cyst. The trophozoites emerge from the cysts in the gut and increase along the intestine’s walls. The illness is accompanied by a foul-smelling, watery discharge and stomach discomfort, and diarrhoea. Mountain streams can carry cysts from wild animals, making hikers, trekkers, and campers vulnerable. Metronidazole is a drug that is used to treat a variety of ailments.
Treatment
Treatment choices are determined by the protozoa that have infected you. Some people are far more successful than others. The effectiveness of treatment is also determined by whether the symptoms of protozoal infection are drug-resistant. Over the last few decades, P. falciparum has developed resistance to several essential medications. Malaria, for example, is a prevalent disease with a simple cure-all around the world. The therapy, however, is dependent on the kind of malaria (Plasmodium falciparum, Plasmodium knowlesi, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax).
Conclusion
Protozoa, like other microorganisms, are common in the natural microbiota, but they can also cause severe sickness. Symptoms of protozoal infection gastrointestinal disorders are commonly connected with exposure to contaminated food and water, putting individuals without access to proper sanitation at risk. Infections may occur even in wealthy nations, and these microorganisms have caused severe epidemics in the past due to contaminated public water sources. Single-celled creatures known as protozoa can occasionally cause sickness. Malaria, giardia, and toxoplasmosis are examples of symptoms of protozoal infections. Depending on the protozoa a healthcare professional suspects, blood tests, stool tests, or biopsies may be used to diagnose symptoms of protozoal infection. Treatment depends on the underlying reason.