T. gondii Morphology? Oocyst? Tachyzoite(arch shaped)? Bradyzoite in a Cyst?
What is the only TRUE DH of Toxoplasma gondii?
Exclusively Cats & they are Asymptomatic
Is Toxoplasma gondii zoonotic? What is the Infective form?
YES, Sporulated Oocysts
What is the IH? What does it do to them?
Rodents. Alters brain function to make them less fearful of cats!
When are you worried about a preg mom & Toxoplasma? When arent you?
If she has IgG but not IgM, she isnt infected & baby is safe. If she has IgM ALSO, then baby is at risk bc tachyzoites can cross placenta
How does it Reproduce?
Both sexual & asexual
Life cycle of T. gondii?
Cat poops → oocysts in poop (infective stage). IH eats poop→ gets infected, goes nuts & predator eats it → here we go again (intestinal & extraintestinal stages)
Sexual Development happens where?
The intestinal epithelium of Cats Only!
Asexual Development happens in the Intestines & Outside of the Intestines. What Life Stage do you see & where are they found?
Intestinal Phase-Merozoites. Extraintestinal Phase- Tachyzoites(rapidly dividing) in the liver, lungs, spleen & lymph node. Can cross the Placental Barrier! Bradyzoite(slow dividing) In cysts found in the brain, heart, skeletal muscle & eye
What are the Faculative IHs(Not necessary to Life Cycle)?
Essentially all Vertebrates&Birds!
The Oocyte is Very Resistant, Where is it Found? How Long is it Excreted?
In Feces of the cat. 7-20days, but an Avg of 5-8days
How long is the Pre-Patent Period(PPP)? What makes it vary?
(A) 3-10 days when cat eats cyst, (B) > 18 days if cat ingests sporulated oocyst, (C) >13 days if tachyzoites are ingested
Clinical Signs in Cats?
High Fever (104-107), CNS signs uncommon, Frequent: Dyspnea, icterus, and abdominal discomfort, Gross lesions(i. Diffuse edema and congestion in the lungs ii. Liver is the most frequently affected abdominal organ → diffuse hepatitis iii. Ocular issues)
What happens when a Cat that has recovered from T. gondii gets infected by Primary Isospora felis?
They will once excrete Oocyts
What happens when a Cat that has recovered from a Primary Isospora felis infection that later becomes infected with T. gondii?
They will have a strong Immunity against T. gondii & will NOT re-excrete T. gondii oocyts after initial shed
Clinical Signs in Sheep?
Major cause of Abortion & focal placentitis. Infected semen can lead to many reproductive issues (with goats as well)
Clinical Signs in Humans?
Most are asymptomatic. Fever, malaise, lymphadenopathy, encephalitis, myocarditis, retinochorditis, Congenital Toxoplasmosis - crosses placenta(Neurologic: retinochoroiditis, hydrocephalus, convulsions)
Clinical Signs in Dogs?
Not Common. Respiratory, neuromuscular, GI
Clinical Signs in a Cow?
Rare & Asymptomatic
Clinical Signs in Pigs?
Usually Asymptomatic, MAY cause Abortion
Clinical Signs in Birds?
Occular and Neurologic manifestations
Clinical Signs in Marine Mammals?
Concurrent infection with S. neurona → associated with higher mortality and severe protozoal encephalitis
Why shouldn't you flush cat poop?
T. gondii Oocytes remain viable in sea water & killing marine mammals
If you wanna avoid Toxo, you should?
COOK MEAT & Careful handling cat poo
How can you dx Toxo?
1. Fecal flotation (cats only) 2. Histopath, PCR, Immunohistochemistry 3. Serology ((a.) IgM indicative if active infection (b.) IgG indicative of previous exposure and immunity)
Basics (goes past quiz 4 but good to know for the midterm)
How does a cestode eat things?
No digestive system - absorbs things through skin
What are the infective larval stages called in cestodes? Where to they like to hang out?
Metacestodes, outside of the intestines in the IH
What is the type of lifestyle of a cestode? Where do they adults live?
Indirect, in the GI of the DH
What are the 3 main body parts of a cestode?
Scolex ("head"), neck, Strobila ("body")
What is the scolex?
Scolex = anterior part attaching to organs (looks like a head)
What is a rostellum?
"Crown of thorns" hooks
Describe the features of the scolex of the order Cyclophyllidea
4 suckers w/ or w/o rostellum (crown of thorns)
What is the neck?
Undifferentiated where segments begin to develop
Describe the features of the scolex of the order Pseudophyllidea? & who is in this group(2)?
(Spirometra, Diphyllobothrium) 2 bothria (longitudinal grooves become flattened to form attachment organs
What is the strobila?
(The "wormy body" part) Contain proglottids (hermaphroditic segments containing male & female repro organs. Segments at the end of worm contain just gravid uterus)
What are proglottids?
Hermaphroditic segments containing male & female repro organs. Segments at the end of worm contain just gravid uterus
Talk through the basic life cycle of a cestode, starting w/ egg
Egg gets eaten by IH → metacestode. Metacestode ingested by DH → intestine → body digested away except for scolex & neck → scolex attaches to intestinal wall → start forming segments (strobilia). Segments form w/ mature repro organs → form eggs & sperm → fertilization. Once segments become gravid- detach & eliminated in DH feces → segments disintegrate to release eggs.
What are some variations on their asexual reproduction?
Self-fertilization & cross fertilization (b/w segments) can occur
Describe how egg goes to metacestode
Egg contains oncosphere (1st stage larvae) → ingested by IH → egg broken down → oncosphere released → blood/lymph → predilection site → develop to metacestode stage
What is an oncosphere?
1st stage larvae, the larvae inside the egg which, once "hatched" inside the IH, will turn into a metacestode
When does most pathogenesis occur in cestode infections?
In the METACESTODE/LARVAL STAGE. Which means the INTERMEDIATE HOSTS are the 1s most harmed
What is a Cysticercus? Where is this?
In the mammalian IH, it is a single fluid filled cyst w/1 invaginated scolex
What is a Coenurus? Where is this?
In the mammalian IH, it is a fluid-filled cyst w/MANY invaginated scolices (each 1 can become mature tapeworm)
What is a Strobilocercus? Where is this?
In the mammalian IH. Cysticercus (fluid filled cyst) w/Evaginated (NOT INvaginated) scolex → Already begins to form asexual proglottids (hermaphroditic segments) while in IH→ proglottids digested away by DH (so pure eggs released from DH)
What is a Hydatid cyst? Where is this? WHO does this? What are the types? What is hydatid sand?
In the mammalian IH. Genus Echinococcus. Large fluid filled cyst w/many invaginated scolices (free or in bunches). Has a thick, laminated cell wall & germinal epithelium (brood capsules bud off of germinal epithelium). Brood capsules are full of heads (protoscolicieses) & when they burst, it is hydatid sand. The 2 kinds of hydatid cysts are Unilocular or alveolar (alveolar looks like a bunch of grapes)
What is a Cysticercoid? Where is this?
In the ARTHROPOD IH. Evaginated scolex embedded in cyst (arthropods)
What is a Tetrathyridium? Where is this?
In the invertebrate IH. Worm-like larvae w/ invaginated scolex. Only in mesocestoides in 2ND IH!!
Metacestodes of Taeniidae can be in which 3 areas of the IH?
In liver & peritoneal membranes or skeletal & cardiac muscle
How do you dx dogs & cats for Taeniidae?
Oncospheres in feces. Also most have cysticercus (single fluid filled cyst w/1 invaginated scolex)
What is the infective stage, what is it called?
The larval stage, called a metacestode
What are the 3 parts of the body? explain the parts
(1) Scolex ("head", anterior part attaching to organs) (2) Neck (undifferentiated where segments begin to develop) (3) Strobila (Maturing units (proglottids) containing male & female sexual organs) → oldest/most mature are near the tail end, & at that point they are just gravid uterus full of oncospheres (eggs)
What is the life cycle of a cyclophyllidea cestode?
Egg/oncosphere ingested by intermediate host → Metacestode → intestines of definitive host → scolex attaches to intestinal wall & neck begins to bud off segments → begins to mature & fertilize → only the gravid proglottid eliminated through feces
Describe the scolex of Taeniidae
4 suckers +/- rostellum w/ hooks
Describe the genital pores of Taeniidae
Unilateral genital pores alternating irregularly (on 1 side of the side of the wormie)
What are the DHs of Taeniidae?
Humans! (Also carnivores such as dogs, cats, etc)
Which tissues do Taeniidae particularly like to hang out in?
In liver & peritoneal membranes or skeletal & cardiac muscle
What is the weird name for this species of Taenia?
DH of T. hydatigena?
Canids & wild felids
IH of T. hydatigena?
Cattle, sheep, swine, wild ungulates
What is the name of the larval stage in the IH? What does this metacestode do/cause (pathologically)?
Cysticercus tenuicollis. Migrates through liver tissue & encysts on peritoneal membrane & causes hemorrhagic tracks. Can cause hepatitis cysticercosis, black disease (C. novyi) in intermediate host.
How can you tell if an IH has been previously exposed to T. hydatigena?
Previously exposed host has greenish nodules on liver
How to remember
Hydatigena will cause black hydrangeas (those poofy blue flowers) to explode from hoofed thing's liver & peritoneum, leaving bloody tracks everywhere. No wonder hoofed things dont like dogs & cats (dogs & cats say, 10/10 colons-taenicolis )