E3- Fungal and Parasitic CNS infections Flashcards
What is the habitat of Cryptococcus neoformans?
Natural reservoirs- soil, bird droppings
What is typically required for Cryptococcus neoformans to cause an infection?
Underlying immunodeficiency prior to infection
What type of disease does Cryptococcus neoformans cause?
Starts as a skin or pulmonary infection and can lead to meningoencephalitis (fatal)
What can be seen on india ink of Cryptococcus neoformans?
Encapsulated yeast
What are the 3 pathogenicity factors of Cryptococcus neoformans?
- Capsule
- Diphenol oxidase that forms melanin from phenol containing substrates
- Able to grow at 37 degrees C
How is Cryptococcus neoformans transmitted?
Inhalation of yeast cells
Is Cryptococcus neoformans communicable?
NO
What form of Cryptococcus can cause more extensive infections?
How can you differentiate this species from Cryptococcus neoformans.?
Cryptococcus gatti
Culture on canavanine glycine bromothymol blue medium (C. gatti will turn blue)
How can Cryptococcus neoformans be dx?
- Samples of CSF (examined w/ india ink)
- Culture on Bird Seed agar/Caffeic acid medium
- Serology (detection of capsule antigen in CSF/serum by latex agglutination)
What type of stain should be used to examine Cryptococcus neoformans?
India ink
What type of plates should be used to culture Cryptococcus neoformans?
Bird Seed agar/Caffeic acid medium
What is typically required for Toxoplasma gondii to cause an infection?
Underlying immunodeficiency prior to infection
What patient populations can Toxoplasma gondii cause severe complicattions?
- Immunocompromised
- Newly infected pregnant women
What is the infective form of Toxoplasma gondii?
Cysts
Which type of trophozoite form of Toxoplasma gondii is considered the actively replicating form?
Tachyzoite-acute disease
Which type of trophozoite form of Toxoplasma gondii is considered the slowly replicating form?
Bradyzoite-chronic disease
Which type of cyst form of Toxoplasma gondii contains bradyzoites?
Zoitocysts
Which type of cyst form of Toxoplasma gondii is seen in seen in cats and is the sexual stage of the parasites lifecycle?
Oocysts
What is the triad of congenital toxoplasmosis?
- Chorioretinitis
- Hydrocephalus
- Intracranial calcifications
How is Toxoplasma gondii transmitted?
- Food borne (usually zoitocysts)
- Zoonotic (oocysts)
- Congenital