E3- Fungal and Parasitic CNS infections

Question 1

What is the habitat of Cryptococcus neoformans?

Answer 1

Natural reservoirs- soil, bird droppings

Question 2

What is typically required for Cryptococcus neoformans to cause an infection?

Answer 2

Underlying immunodeficiency prior to infection

Question 3

What type of disease does Cryptococcus neoformans cause?

Answer 3

Starts as a skin or pulmonary infection and can lead to meningoencephalitis (fatal)

Question 4

What can be seen on india ink of Cryptococcus neoformans?

Answer 4

Encapsulated yeast

Question 5

What are the 3 pathogenicity factors of Cryptococcus neoformans?

Answer 5

• Capsule
• Diphenol oxidase that forms melanin from phenol containing substrates
• Able to grow at 37 degrees C

Question 6

How is Cryptococcus neoformans transmitted?

Answer 6

Inhalation of yeast cells

Question 7

Is Cryptococcus neoformans communicable?

Answer 7

NO

Question 8

What form of Cryptococcus can cause more extensive infections?
How can you differentiate this species from Cryptococcus neoformans.?

Answer 8

Cryptococcus gatti

Culture on canavanine glycine bromothymol blue medium (C. gatti will turn blue)

Question 9

How can Cryptococcus neoformans be dx?

Answer 9

• 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)

Question 10

What type of stain should be used to examine Cryptococcus neoformans?

Answer 10

India ink

Question 11

What type of plates should be used to culture Cryptococcus neoformans?

Answer 11

Bird Seed agar/Caffeic acid medium

Question 12

What is typically required for Toxoplasma gondii to cause an infection?

Answer 12

Underlying immunodeficiency prior to infection

Question 13

What patient populations can Toxoplasma gondii cause severe complicattions?

Answer 13

• Immunocompromised

- Newly infected pregnant women

Question 14

What is the infective form of Toxoplasma gondii?

Answer 14

Cysts

Question 15

Which type of trophozoite form of Toxoplasma gondii is considered the actively replicating form?

Answer 15

Tachyzoite-acute disease

Question 16

Which type of trophozoite form of Toxoplasma gondii is considered the slowly replicating form?

Answer 16

Bradyzoite-chronic disease

Question 17

Which type of cyst form of Toxoplasma gondii contains bradyzoites?

Answer 17

Zoitocysts

Question 18

Which type of cyst form of Toxoplasma gondii is seen in seen in cats and is the sexual stage of the parasites lifecycle?

Answer 18

Oocysts

Question 19

What is the triad of congenital toxoplasmosis?

Answer 19

• Chorioretinitis
• Hydrocephalus
• Intracranial calcifications

Question 20

How is Toxoplasma gondii transmitted?

Answer 20

• Food borne (usually zoitocysts)
• Zoonotic (oocysts)
• Congenital

Question 21

What forms of Toxoplasma gondii are seen on dx?

Answer 21

Zoitocysts and trophozoite forms

Question 22

How is Toxoplasma gondii dx?

Answer 22

• ELISA
• PCR
• Isolated from CSF

Question 23

What is the habitat of Naegleria fowleri?

Answer 23

Soil and fresh water (facultative environmental protozoan)

Question 24

What form of Naegleria fowleri is infectious?

Answer 24

Flagellate (trophozoite)

Question 25

What form of Naegleria fowleri is reproductive and feeds on bacteria?

Answer 25

Amoeboid (trophozoite)

Question 26

What form of Naegleria fowleri is formed in tissue, causing destruction and phagocytosis of RBCs and WBCs?

Answer 26

Amoeboid (trophozoite)

Question 27

What is the life-cycle of Naegleria fowleri?

Answer 27

- Infective flagellate form enters the nasal passage and then transforms into the amoeboid form - It migrates along the olfactory nerve to the brain - Causes severe necrosis of the olfactory bulb and brain tissue through sucker apparatus

Question 28

How is Naegleria fowleri transmitted?

Answer 28

Entry through the nasal passageway

Question 29

What type of infection does Naegleria fowleri cause?

Answer 29

Primary Acute Meningoencephalitis

Question 30

Does a Naegleria fowleri infection require an immunocompromised host?

Answer 30

No

Question 31

Is Naegleria fowleri spread person-to-person or via contaminated drinking water?

Answer 31

No

Question 32

There is increasing incidence of Naegleria fowleri infections via what?

Answer 32

Neti pots

Question 33

How is Naegleria fowleri dx?

Answer 33

- Drop CSF on plate with E. coli - Look for clearing zones - Pick up amoeba and place in distilled water - Look for flagellated form

Question 34

Is chlorine effect in killing Naegleria fowleri?

Answer 34

No

Question 35

What is the infective stage of Acanthamoeba?

Answer 35

Trophozoite

Question 36

What is seen in the trophozoite form of Acanthamoeba?

Answer 36

Spiked pseudopodia

Question 37

How is Acanthamoeba transmitted?

Answer 37

Enters through the lower respiratory tract or ulcerated/broken skin

Question 38

What are the 3 clinical syndromes caused by Acanthamoeba?

Answer 38

- Granulomatous Amoebic Meningoencephalitis - Ocular Acanthamoebiasis Keratitis and Uveitis - Disseminated disease

Question 39

How does Acanthamoeba cause a Granulomatous Amoebic Meningoencephalitis infection?

Answer 39

Hematogenous route to the brain

Question 40

How does Acanthamoeba cause an Ocular Acanthamoebiasis Keratitis and Uveitis infection?

Answer 40

Introduced by trauma to the eye, followed by contamination with cysts

Question 41

What form of Acanthamoeba can be seen in tissue?

Answer 41

Both trophozoite and cysts

Question 42

How is Acanthamoeba dx?

Answer 42

- Tissue sample - Keratitis cornea scrapings - Postmortem brain biopsy

Question 43

What is not efficient in dx Acanthamoeba?

Answer 43

Examining CSF

Question 44

What type of infection can Balamuthia mandrillaris cause?

Answer 44

Granulomatous Amoebic Meningoencephalitis

Question 45

What form of Balamuthia mandrillaris is infectious?

Answer 45

Both the trophozoite and cyst forms are infectious

Question 46

What is seen in the trophozoite form of Balamuthia mandrillaris?

Answer 46

Binucleate | Flat pseudopodia

Question 47

How is Balamuthia mandrillaris transmitted?

Answer 47

Enters through the lower respiratory tract or ulcerated/broken skin

Question 48

What geographic location is Balamuthia mandrillaris most commonly found?

Answer 48

``` Southern states (California) Latin America ```

Question 49

What does Balamuthia mandrillaris allow to replicate within it? Why?

Answer 49

Legionella pneumophilia | Increases its virulence

Question 50

What form of Balamuthia mandrillaris can be seen in tissue?

Answer 50

Both trophozoite and cysts

Question 51

How is Balamuthia mandrillaris dx?

Answer 51

Only co-cultured with primate hepatic cells or human brain cells

Question 52

Why can Balamuthia mandrillaris not be cultured easily?

Answer 52

It does not feed on bacteria