1. APICOMPLEXA
Protozoa characterized by the presence of an apical complex which allows the organism to invade host cells

2. Very well adapted to be intracellular in majority of their life stages.
Reproduction both sexual and asexual.
Haploid most of their lives, only zygote is diploid.
Three major groups: gregarines
coccidia
piroplasmas

3. Developmental Stages of Coccidians
Sporogony, sporocysts are usually made outside body and directly ingested by new host. Coccidian are usually distinguished by the number of sporocysts within the oocyst
Merogony, merozoites
Gamogony, gametocytes

4. Intestinal Coccidia Eimeria tenella Kingdom Protista
Subkigdom Protozoa
Phylum: Apicomplexa
Class: Coccidia
Order: Eimeriida
Family: Eimeriidae
Genus: Eimeria
Species: tenella

5. Lives and multiplies within epithelial cells of the intestine
ingestion
Few days
Unsporulated oocyst
In feces, uninfective
Sporulated oocyst
In feces, infective
Excystation
Asexual
reproduction
merozoites

6. 5.5 days 7 days sporozoite Micro- and macro-gametes 1st gen.
merozoites
5.5 days
2nd gen.
merozoites
7 days
3rd gen. merozoites

7. Look at slides 97 and 98. You should see the different stages in the intestine of a bird.
Identify the epithelial cells of the intestine with the 4X lens, then zoom in.
Slide 97 is a 5.5 day old infection, you should be able to see 2nd and 3rd generation of merozoites within the intestinal cells, and bursting out of them, some will be within cysts.
On slide 98 you will see a 7 day old infection in which you should be able to recognize micro- and macro-gametes.

8. Intestinal Coccidia Toxoplasma gondii Kingdom Protista
Subkigdom Protozoa
Phylum: Apicomplexa
Class: Sporozoasida
Order: Eucoccidiorida
Family: Sarcocystidae
Genus: Toxoplasma
Species: gondii

10. Toxoplasma gondii has very low host specificity, and it will probably infect almost any mammal.
An obligate intracellular parasite .
Definitive hosts are cats, which are infected by eating rodent intermediate hosts

11. Next host inhales the oocyst human, cat, cattle, sheep
Life cycle
sporulated
Next host inhales the oocyst
human, cat, cattle, sheep
unsporulated
Intestinal phase in cats only
tachyzoites
Extraintestinal phase

12. New host: cat and/or human
Ingestion of raw meat
Bradyzoite, in brain tissue
New host: cat and/or human
sporulated
Inhalation of oocysts
unsporulated

13. Examine slide 100. You should see bradyzoite or a tissue cyst full of bradyzoites

14. Ultraestructure of Toxoplasma gondii