0112100930 - MFM II - Toxoplasmosis (Kunigelis)

The apical complex that extends and retracts to facilitate host cell penetration by acting like a drill bit.

1) two apical rings
2) a conoid that acts like the drill bit
3) polar wing - dense granular material that connects longitudinal microtubles
4) Rhoptries - enzyme releasing structure that assists during penetration
5) micronemes - modified secretory vesicles

1) Mono or heteroxenous (one or more hosts)
2) Intracellular asexual reproduction
3) Live in GI epithelium, kidneys, RBCs in vertebrate or invertebrates

400 to 4000 congenitcal cause birth defects, blindness

cats by ingesting
1) Zoitocysts in bradyzoites (slow dividing cells) in meat
2) Oocysts contain sporocysts with sporozoites (feces to soil). coming from cat to soil
3) Occasionally tachyzoites (motile form)

1908 in N. African desert rodent, the gondi.

circulatory system can be infected, which means that it can spread to nearly any tissue type.

man, pig, sheep. man is an accidental host by ingestion of infected meat.

stage in coccidia that develops within a zoitocyst which is slow multiplication

daughter cell from schizogony (which is the point in asexual reproduction where numbers are increasing)

daughter cell from sporogony

rapid developing stage

tissue phase of coccidia with an internal septum and thousands of bradyzoites

formation of two daughter cells from a mother cell

schizogony (asexual reproduction by multiple fission)

asexual reproduction in which multiple mitosis takes place, followed by synchronoous cell division to liberate all daughter cells at once

multiple fission of zygote = sporont

1) oocyst in cat feces = 2 sporocysts each with 4 sporozoites are ingested accidentally
2) eating undercooked infected meat (beef, pork, lamb) containing bradyzoites

1) Cat eats Pseudocysts (bradyzoites) or free oocysts (sporozoites)
2) Bradyzoites or sporozoites enter intestinal epithelium to become trophozoites
3) trophozoites undergo schizogony to yield 2-40 merozoites
4) merozoites in intestinal cell will rupture
5) can infect neighboring cells or can form gametocytes - microgametocytes (male) or macrogametocytes (female)
6) microgametocytes enter cells containing macrogametocytes
7) gamete fusion yields zygote -> oocyst
8) oocyst enters intestinal lumen
9) oocyst is pooped out
10) oocyst undergoes sporulation in the soil yielding sporozoites, which we could pick up accidentally

1) ingestion of oocysts or pseudocysts
2) digestive enzymes rupture oocyst or pseudocyst
3) bradyzoites or sporozoites enter intestinal wall cells
4) bradyzoites or sporozoites travel along hepatic portal to liver
5) liver macrophages ingest what is now tachyzoites or bradyzoites. notice sporozoites are not tachyzoites.
6) liver parenchymal cells become infected
7) Tachyzoites reproduce by endodyogeny
8) cell lysis and release of trophozoites
9) tachyzoites are ingested by macrophages and distributed throughout the body (including fetal infection)
10) new liver cells are infected, host immune response slows down reproduction enough to form pseudocysts
11) endogyogeny continues within pseudocysts -> many bradyzoites
12) dormancy for years or excystment and replication once immune response settles

Pseudocyst

Deep freeze for 3 days or 140F when cooking.

1) French
2) Dutch
3) American
4) Japanese

flu like symptoms occur when the intestinal wall is first attacked and then again as the cysts move to lymph of stomach and liver

symptoms are prolonged and lesions can occur in the lungs, liver, heart, brain, and eye

When pseudocyst rupture (years after infection) then bradyzoites are released and a site of severe inflammation may occur. Further cysts can occur as encephalitis, paralysis, blindness, myocarditis, pneumonia all depending on where the cysts occur.

immunocompromised

1) Immunodeficiency
2) exposure to cats
3) eating raw or partially cooked meat

sporogamy (sporozoite)

Avoid changing the litter box
Change litter every 2 days.

no tx for the average person