Parasitic Protozoology

Quiste de Entamoeba histolytica
Entamoeba histolytica cyst
Protozoa are microscopic eukaryotic organisms. Formerly they were classified as animals (Animalia kingdom) and today it is known that they have some characteristics that they share with the vegetables, being a very diverse group, with relation of remote kinship. There are classifications that encompass them in Protist, with different phyla, being a paraphyletic group. Others create for them a eukaryotic kingdom Protozoa. Parasitic protozoa are a minority and need a host. Sometimes to overcome disfavorable conditions become cyst.

Amoebas are protozoans that move by movement accomplished by protrusion of cytoplasm involving the formation of pseudopodia (amoeboid movement). The best known parasite is Entamoeba histolytica, which parasites dogs and people. It causes amoebic dysentery, feeding on the bolus of food and intestinal bacteria, even the intracellular fluids of the cells it destroys.

Intestinal ulcer caused by Entamoeba histolytica
Intestinal ulcer caused by Entamoeba histolytica
Giardia lamblia, intestinalis or duodenalis is a flagellate protozoan that lacks certain organelles such as mitochondria and the Golgi apparatus and produces intestinal conditions that can become serious. It was the first microscopic parasite found in the human species by Anton van Leeuwenhoek when he observed under the microscope fecal matter, but at that moment nothing was known about protozoa.

The protozoan Trichomonas vaginalis causes trichomoniasis, a sexually transmitted disease that in some populations of industrialized countries has an incidence of 70%. Most people infected do not have any symptoms. Symptoms experienced include pain, burning or itching in the penis, urethra, or vagina.

Leishmaniasis is a disease caused by the protozoan Leishmania, transmitted through mosquitoes. It is a disease that affects dogs and humans (zoonoses). Some species of Leishmania cause severe ulcers on the skin leaving permanent scars.

Trypanosoma causes african trypanosomiasis, also known as sleeping sickness. The trypanosomes are passed in the saliva of the tsetse fly. One to three weeks after the bite, in the first stage of the disease, there are headaches, fevers, and joint pains. Weeks to months later the second stage begins with confusion, poor coordination, and trouble sleeping. Without treatment it typically results in death.

Apicomplexa is a group of endoparasite protists that penetrate the inside of cells. Cryptosporidium causes a diarreic disease; Toxoplasma the disease toxoplasmosis; Plasmodium malaria; and Babesia infect the blood and cause a hemolytic disease known as babesiosis.

Toxoplasmosis is an infectious disease caused by the protozoan Toxoplasma gondii, an obligate intracellular parasite. It is a zoonosis that is transmitted from animals to humans through different routes of infection, being definitive hosts the cat and six other species of felines, but the most important route of infection are contaminated food. It has a high incidence in Africa and America, with 80% being asymptomatic infestations, and in other cases chronic.

Malaria is a disease caused by the genus Plasmodium, through the mosquitoes of the genus Anopheles. It has a high incidence worldwide, causing two to three million deaths a year.

Anopheles gambiae, transmisor de la malaria
Anopheles gambiae, transmitter of malaria
Babesiosis is caused by the protozoan Babesia, which attacks the red blood cells and transmitted by ticks. In the cattle causes the denominated Texas cattle fever.


1. Protozoans. General characters and classification

- Reading: Wikipedia. Protozoa
- Video: Mr. Rawlings Biology. The World of the Protozoa


2.- Amoebiasis. Entamoeba histolytica. Free-living Amoebozoa infection

- Reading: Wikipedia. Amoebiasis
- Reading: Wikipedia. Entamoeba histolytica
- Reading: Wikipedia. Free-living Amoebozoa infection
- Video: DrER.tv. Amebiasis


3. Intestinal Flagellates. Giardia lamblia

- Reading: Wikipedia. Flagellate
- Reading: Wikipedia. Giardia lamblia
- Presentation: Biology Teaching Centre. Flagellates (pdf)


4. Trichomonanida. Trichomonas vaginalis

- Reading: Wikipedia. Trichomonanida
- Reading: Wikipedia. Trichomonas vaginalis


5. Leishmania

- Reading: Wikipedia. Leishmania
- Video: Let's Learn About Bugs. What is Leishmaniasis? An introduction and overview


6. Trypanosoma

- Reading: Wikipedia. Trypanosoma
- Video: videosINBEB. Animated life cycle of T. cruzi in the human host


7. Apicomplexa. General characters and classification

- Reading: Wikipedia. Apicomplexa
- Vídeo: iBiology. David Roos (U Penn) Part 1: Biology of Apicomplexan Parasites
- Vídeo: iBiology. David Roos (U Penn) Part 2: The apicomplexan plastid


8. Cryptosporidium

- Reading: Wikipedia. Cryptosporidium
- Video: Paul Cochrane. Cryptosporidium: What You Should Know


9. Cyclospora, Cystoisospora, Sarcocystis and Toxoplasma

- Reading: Wikipedia. Coccidia
- Reading: Wikipedia. Cyclospora cayetanensis
- Reading: Wikipedia. Cystoisospora belli
- Reading: Wikipedia. Sarcocystis
- Reading: Wikipedia. Toxoplasma gondii
- Video: Maddie's Fund Education. Coccidia in a Shelter Setting


10. Plasmodium and Babesia

- Reading: Wikipedia. Plasmodium
- Reading: Wikipedia. Babesia
- Video: Armando Hasudungan. Malaria - Plasmodium


Identification of protozoans parasites. Virtual Lab


Resources for further learning

- Lectura: Wikipedia. Acanthamoeba
- Lectura: Wikipedia. Balamuthia mandrillaris
- Lectura: Wikipedia. Naegleria


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Parasitology

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