Parasitology: Eimeria tenella Study

Study Notes

Parasitology is the study of parasites and their interactions with hosts.
Protozoa are single-celled eukaryotic organisms. There are various phylum and class classifications within the Protozoa kingdom.
Eimeria tenella is a protozoan parasite.
Eimeria tenella is an intracellular endoparasite found in the epithelium of intestinal caeca of chickens and small ducks.
The definitive host is only chickens.
The infective stage is the sporulated oocyst.
Infection occurs by ingesting sporulated oocysts in contaminated food or water.
The diagnostic stage is the unsporulated oocyst.
The disease caused by Eimeria tenella is coccidiosis.
The life cycle involves sporulation, excystation, sporocysts, sporozoites, merozoites, and formation of gametes. It occurs outside the host, requiring oxygen.

Kingdom: Protozoa
Subkingdom: Bacillata
Infrakingdom: Alveolata
Phylum: Apicomplexa
Class: Conoidasida
Order: Eucoccidiorida
Toxoplasma gondii is an endoparasite found in tissues (skeletal muscle, myocardium, brain, and eyes).
The definitive host is a cat.
Intermediate hosts include man, birds, rodents (mice, rats and rabbits), and sheep.
The infective stage for humans include sporulated oocysts and tissue cysts for cats.
The diagnostic stage are tachyzoites in blood or bradyzoites in muscle tissues.
The disease caused by Toxoplasma gondii is Toxoplasmosis.
Infection for humans: eating undercooked meat, contaminated food/water with cat feces/contaminated soil, blood transfusion or organ transplant, transplacentally from mother to fetus.

The life cycle involves sporulated oocysts, sporozoites, tachyzoites, tissue cysts, and bradyzoites.
Sporulated oocysts are expelled in cat feces and become infective in the environment.
Intermediate hosts ingest sporulated oocysts leading to infection.
In the definitive host (cat), the parasite undergoes sexual reproduction.
Formation of gametes and fertilization leads to oocyst development, then the oocysts are expelled.

A method used for parasite identification in stool samples.
Zinc sulphate flotation is a commonly used method for separating parasites.
The method involves layering the sample in a solution of increasing density, so that parasitic components are floated to the surface enabling easier visualization.