Protists Flashcards
Which species of Cyclospora is found in humans
What clinical signs are associated
C. cayetanensis
Diarrhea in people in South America
In what animal and organ is Klossiella normally found
In the kidneys of horses and mice, usually nonpathogenic
What are some hosts of Cyclospora
Snakes, primates, rodents, insectivores (and moles)
How is Cyclospora usually transmitted to people?
Ingest contaminated water or produce (raspberries!!!)
Define some terms relative to the life cycle of Protista. Zoite Sporozoite Tropozoite Schizigomy Gametogeny Zygote
Zoite - motile form
Sporozoite - haploid stage
Zygote - diploid stage
Tropozoite - stage once the protist has entered a cell
Schizogony - split asexually (schizizoites are daughter cells of this split)
Gametogeny - sexual reproduction
For Cystoisospora, what stage does the life cycle arrest at
Arrested sporozoite stage
Characterize the oocyst of Cystoisospora
No polar cap
2 sporocysts each with 4 sporozoites in them
What is the prevalence of Cystoisospora in regards to age ranges
More prevalent diseases in young animals
What part of the animal do Sarcosysts live in?
Muscle
What are key features of the Sarcocystis life cycle
Requires a vertebrate intermediate host where schizonts develop in the endothelial cells, then sporulated sporocysts form oocysts that are seen in the muscles
Carnivorous final host where gametogony only occurs in the intestinal cells
Why is EPM only seen in the Americas
The intermediate host is the the opossum… Only 4 species, in Americas
Sheds sporocysts into environment
What is EPM and what organism causes it?
Equine protozoal myeloencephalitis
Sarcocystis neurona
What is one characteristic of EPM infection?
Formation of schizonts in dividing cells in equine (neural) tissues
Cats, skunks, & 9 banded armadillos can have muscle stages
What role do cattle serve in the Besnoitia besnoiti life cycle
Intermediate hosts
What is the final host of most Besnoitia species of veterinary significance
Cats
What are the intermediate hosts of 2 species of Besnoitia besides B. Besnoiti
B. Darlingi - opossums in US
B. Wallacei - rodents in US
Other B. Species affect donkeys, mainly miniature donkeys
What does a facultative heteroxenous life cycle refer to?
Ex. Of one organism that has this type of life cycle.
Can utilize paratenic hosts… Can be completed in a single host or can utilize other hosts for completion of the life cycle
Toxoplasma
In what animal was Toxoplasma gondii first found
A gundi, a small rodent in North Africa
Which life stage of people are most severely affected by Toxoplasma and which life stage of the agent is responsible for disease?
Newborn infants infected in utero
Tachyzoite
What form of Toxoplasma gondii is shed in cat feces
Oocysts
How are people infected with Toxoplasma gondii
Ingest raw/undercooked meat (visceral infection with small cysts in paratenic hosts; with the general exception of beef) or oocysts from contaminated soil or vegetables (enteric infection in cats, shed in feces).
What are the 4 forms that toxoplasma gondii appears as in human hosts
- Chronic infxn with bradyzoites
- Acute disease with multiplying tachyzoites following first exposure
- Infection of infants in utero
- Recrudescence by reactivation of Brady into tachyzoites
What needs to happen for recrudescence of an existing infection to occur?
Immunosupression
When is a fetus in danger of being infected with toxoplasma
When the mother is infected for the very first time while pregnant
Why are signs worse when the fetus is infected during the first trimester
More cells are rapidly dividing
What species of Protista is normally associated with posterior flaccid paralysis in puppies
Neospora caninum
How are most puppies with Neospora caninum derived paralysis infected
Transplacentally
What other species are affected by Neospora caninum, and how
Cow, causes abortions. Usually no repeat abortions.
What are vectors of hepatozoon of different species
Hepatozoon canis and Hepatozoon americanum in dogs transmitted by tick… Rhipicephalus sanguineus and Amblyomma maculatum respectively
Species in rodents vectored by mites
Species in reptiles vectored by mosquitoes
Describe the life cycle of Hepatozoon americanum in reference to its hosts
Ingested by tick as gamonts in blood,
sexual replication in tick gut makes oocysts in body cavity of tick,
Dog eats tick or paratenic host (infected rabbit)
Schizonts occur in various tissues and gamonts in white blood cells
What clinical signs are associated with Hepatozoon infection in dogs
How is it treated
Arthritis pain
Relapses are expected
No real Tx, control with quinolone anticoccidial agent
What is the only vertebrate host cell affected by Babesia
Red blood cells
What species causes bovine piroplasmosis
Babesia bigemina, often gather in pairs to destroy RBCs
How is Babesia bigemina transmitted
Rhipicephalus ssp.
How is Babesia transmitted from tick to tick
Vertically, sporozoites multiply in the tick ovary infecting larva that hatch from her eggs
What is the vector of Babesia divergans and why is it important
Ixodes ricinus - it is a 3 host tick and the parasite is transmitted to all three stages. Humans can be affected zoonotic
What species of Babesia affect dogs and what are their intermediate hosts
What are signs associated with disease
Babesia canis and Babesia gibsoni
Rhipicephalus sanguineus and Haemaphysalis longicornis, H. bispinosa
Hematuria and jaundice
How is Theileria is different from Babesia in infection of cells
Theileria infects lymphocyte and schizonts in lymphocytes induce them to undergo proliferation and division
How is Theileria transmitted and what is the associated disease
Via tick bite
East coast fever in cattle (enlarged lymph nodes) and deer - affects erythrocytes, lymphocytes and endothelial cells
What agent and vector are associated with equine piroplasmosis
Theileria equi
Amblyomma cajennense
What do people infected by Babesia and Theileria often have in common
Been splenectomized
How does Cytauxzoon differ from Theileria?
Schizonts in vertebrates occur in macrophages instead of lymphocytes
How does Cytauxzoon kill cats
Turn blood into macrophage jelly, occlude the lumen, no room for RBCs in lungs spleen and LNs
What is the natural host of Cytauxzoon felis
Bobcat, Lynx rufus
What is the vector of Cytauxzoon felis to cats
Amblyomma americanum
What is the best way to prevent a cat’s infection with Cytauxzoon
Seresto collar
What is the causative agent of malaria
Plasmodium
What species can be affected with malaria
All primates, birds, rodents, and reptiles (mainly lizards)
Brief overview of life history of plasmodium
Sporozoites injected into host during mosquito feeding
Enter hepatocytes and become trophozoites, then undergo schizogony, cell lysis merozoites enter RBCs and undergo second round of schizogony. Cycle continues with RBCs
Eventually merozoites develop into gametocytes and are ingested by mosquito. Within mosquito they mature and develop fertilized zygotes.
How does the life cycle of plasmodium manifest as clinical signs
Cycles of schizogony manifest of cycles chills (schizogony within cells) and fever (cells rupture and release merozoites)
Haemoproteus are parasites of what animals
Associated disease?
Birds, turtles and lizards
Considered nonpathogenic
What are vectors of Haemoproteus
Culicoides, hippoboscidae, chrysops - ingest erythrocytes containing gametocytes
What are Leucocytozoon parasites of
Domestic and wild birds
What are vectors of Leucocytozoon
Black flies (simulium)
Which species develops megaloschizonts in the liver of chickens
Leucocytozoon caulleryi
Which species are parasitized by Hepatocystis?
Lower monkey, fruit bat and old world squirrels
Give examples of photosynthetic Stramenopiles
Brown seaweed, diatoms
Give an example of non photosynthetic Stramenopiles
Opalinids - small group of amphibian parasites
Saprolegniales - water molds
What is the common name for Saprolegniales
Water molds
How do water molds get their energy
Saprophytic - feed on dead things
Weakly parasitic
How do water molds reproduce
Asexual - sporangia (structures containing spores) release zoospores (motile asexual spore that uses a flagellum for locomotion)
Sexual - gametangial contact
Name one disease caused by water molds bad the animals severely affected
Pythiosis
Dogs and horses
What are the three parts of brown algae
Root-like holdfast, stem-like stipe, and a leaf-like blade
What is the host of Blastocystis hominis
Humans and a wide range of animals (birds, mammals, reptiles, amphibians and arthropods)
Does water treatment kill 100% of Blastocystis?
No, Blastocystis populations remain high in sewage
What type of organisms make up the classification of Excavates
Amoebas
What is the cause of primary amebic meningoencephalitis
Naegleria fowleri
How is Entamoeba histolytica transmitted
Human to human via feces
What is a diagnostic histological legion of Entamoeba histolytica
Upside-down champagne glass shaped lesions in intestinal mucosa
What is unique about Entamoeba histolytica
They (only amoebas to) eat red blood cells
What is nonpathogenic amoeba that is morphologically indistinguishable from Entamoeba histolytica
Entamoeba dispar
How does Acanthamoeba typically infect people
Dirty contact lenses, causing eye disease (keratitis)
How is Acanthamoebic keratitis often misdiagnoses
As herpes simplex virus infection
What is disease progression to Acanthamoebic encephalitis
Inefection in skin, hematogenous spread to the brain of immunosuppressed individuals
What is another organism besides Acanthamoeba that can cause granulomatous amebic encephalitis
Balamuthia, also usually involves skin lesions and associated with a finger stick.
