Parasitology: Protozoa

Protozoa

• Protozoa are single-celled organisms that belong to the group of eukaryotes.
• They are divided into two main groups: protozoa of the digestive and urogenital tract, and protozoa of blood and tissues.

Rhizopodea

• The class Rhizopodea includes amoebae and consists of Entamoeba dysenteriae, free-living amoeba, and Giardia lamblia.
• Entamoeba dysenteriae parasitizes in the human large intestine.
• The histolytica form of Entamoeba dysenteriae is the vegetative form and consists of a central granular zone of endoplasm and a peripheral clear homogeneous zone of ectoplasm.
• The minuta form of Entamoeba dysenteriae is the luminal form and has less differentiated ectoplasm compared to endoplasm.

Transmission of Entamoeba dysenteriae

• Entamoeba dysenteriae is transmitted through the fecal-oral route.
• The cyst form of Entamoeba dysenteriae is the infective stage.

Diagnosis of Entamoeba dysenteriae

• Diagnosis is made by examining multiple stool samples.
• The material used for diagnosis is stool, aspirates, and material obtained by biopsy.
• Stained preparations are used to detect the parasite.

Free-Living Amoeba

• Free-living amoeba resides in soil and freshwater.
• It is the causative agent of amoebic meningoencephalitis.

Balantidium coli

• Balantidium coli belongs to the class Ciliatea.
• It parasitizes in the human large intestine.
• The vegetative form of Balantidium coli is called a trophozoite.
• The cyst form of Balantidium coli is the infective stage.

Giardia lamblia

• Giardia lamblia belongs to the class Zoomastigophorea.
• It causes giardiasis.
• The vegetative form of Giardia lamblia parasitizes in the duodenum and initial parts of the jejunum.
• The cyst form of Giardia lamblia is the infective stage.

Parasitology

• Amebic dysentery is a disease caused by Entamoeba dysenteriae.
• The causative agent of amebic dysentery is Entamoeba dysenteriae.
• Entamoeba dysenteriae is a protozoan.
• Leishmania Donovani is the causative agent of visceral leishmaniasis.
• The vector for Leishmania Donovani is Phlebotomus.

Malaria

• Plasmodium vivax causes Tertian malaria.
• Plasmodium malariae causes Quartan malaria.
• Plasmodium falciparum causes Tropical malaria.
• Malaria is transmitted by mosquitoes of the genus Anopheles.

Toxoplasmosis

• Toxoplasma gondii is a protozoan.
• Diagnosis of toxoplasmosis is made by detecting parasites in the blood or using an ELISA test.
• Toxoplasma gondii has an affinity for embryonic cells.

Helminths

• Dicrocoelium lanceolatum is a small fluke that parasitizes in the liver and bile ducts.
• Fasciola hepatica is a large fluke that parasitizes in the liver and bile ducts.
• Schistosoma haematobium is a parasite of the abdominal vein.
• Schistosoma mansoni is a parasite of the abdominal vein.
• Schistosoma japonicum is a parasite of the portal vein system.

Tapeworms

• Diphyllobothrium latum is a fish tapeworm.
• Hymenolepis nana is a small tapeworm.
• Taenia solium is a pig tapeworm.
• Taenia saginata is a beef tapeworm.
• Taenia echinococcus is a dog tapeworm.

Roundworms

• Ascaris lumbricoides is a roundworm.
• Enterobius vermicularis is a pinworm.

Ectoparasites

• Sarcoptes scabiei hominis is the causative agent of scabies.
• Pediculus capitis is the head louse.
• Pediculus vestimenti is the body louse.
• Pediculus pubis is the pubic louse.
• Malassezia furfur causes pityriasis versicolor.