Mycology and Parasitology

Question 1

Can mycoses be transmitted from animals to humans?

Answer 1

YES, fungal infections can be transmitted from animals to humans
-ringworm is an an example that pets pass on to their owners

Question 2

Characteristics of Fungus

Answer 2

• eukaryotic (nucleus!)
• cell wall (chitin and glucan)
• no cholesterol in membrane (ergosterol instead)

Question 3

Forms of fungus?

Answer 3

Yeast form:

• intracellular usually
• reproduce by budding (pseudohyphae) or binary fission

-ex: candida albicans (part of our natural flora but if immunocompromised (cancer patient, baby, transplant patient taking suppressors) or if it travels somewhere it shouldnt be (like via aspiration) could lead to infection)

Mold form:
multicellular, hyphae, mycellium

Question 4

What is a thermally dimorphic fungal infection?

Answer 4

fungal infection that has both yeast and mold forms
-YEAST form (37 degrees Celsius - BODY TEMP)

-MOLD form (25 C - ROOM TEMP)

*“yeast in the beast, mold in the cold”
(its the same organism just in different forms)

Question 5

How do we classify fungal diseases?

Answer 5

by location of the infection:

Superficial: outermost layer of skin & hair
-affect hair, nails

Cutaneous: keratinized layer of skin, hair and nails

• Itching, scaling, ring like patches
• dermatophytes (ringworm)

Systemic: thermally dimorphic
- within the body (could move throughout too, ex. Lung, brain

Opportunistic: (when you’re) immunocompromised
-candidia albicans

Question 6

WHat can you tell me about systemic mycoses

Answer 6

• ENDEMIC - A lot of these have same symptoms so “geographic region*** is super important in differentiating
• Disseminating - If infection get bad enough they can move out of lungs and into blood stream
• Ability to cause infections in both healthy and immunocompromised individuals
• Thermally dimorphic
• Respiratory infections

Question 7

Blastomyces dermatitidis - transmission

Answer 7

• inhalation of conidia
• found in soil and leaf litter
• converts to yeast form in lungs because of temperature change

Question 8

What is the endemic area or source of Blastomyces dermatitidis?

Answer 8

• Southeast US
• Ohio Mississippi River Valleys
• Great Lakes

buzz word: broad based budding yeast

Question 9

What is the endemic area or source of Coccidiodes immitis?

Answer 9

Found in the soil of:

• The desert Southwest U.S.
• California
• Mexico
• Central & South America

buzz word: *spherule

Question 10

When does the fungus switch forms after entering the host?

Answer 10

NOT immediately, because they are SLOW growers

-probably 12-24 hours

Question 11

Which of these organisms can disseminate (spread to other regions of the body)?

Answer 11

• All of these organisms can disseminate – it really depends on the immune system of the host.
• If it keeps it in check, wont disseminate

Question 12

What is the endemic area or source of Histoplasma capsulatum?

Answer 12

-states bordering the Ohio River Valley and the lower Mississippi River

buzz words: Spelunking, caves, atic, barn
(all of these are places where bird or bat droppings are found)

Question 13

WHat does spelunker’s lung mean to you?

Answer 13

• Histoplasma capsulatum

- signs and symptoms are similar to TB, EXCEPT TB has the BLOODY cough, not just a cough

Question 14

What is the endemic area or source of paracoccidioides brasiliensis?

Answer 14

Found in the soil of:

• Central America
• South America

buzz word: Pilot wheel

-it’s able to go dormant and reactivate when you become immunosuppressed

Question 15

What the hell is medical parasitology?

Answer 15

the study of invertebrate animals capable of causing disease in humans and animals.

Question 16

ectoparasite vs. endoparasite

Answer 16

1. ectoparasite - lives on the surface of hosts
   - ticks, lice
2. endoparasite - lives within the body of hosts
   - worms / protozoa

Question 17

How does the parasite cause damage?

Answer 17

Nutritional deprivation
-worms in GI tract steal your food!

Direct trauma/obstruction
-so many worms! blockage!

Inflammation
-damage from your own immune system

Question 18

What is the endemic area or source of Giardia Lamblia?

Answer 18

• streams
• lakes
• wild animals
• domestic animals
• contaminated water, fruits, and vegetables

*buzz words: watery diarrhea and fatty stools (floaters)

Question 19

How can we diagnose Giardia Lamblia?

is there a treatment?

Answer 19

microscopy of stool sample, 1 per day for 3 days (so they don’t miss it)

• watery diarrhea (as opposed to bloody)
• also don’t worry about the treatment but there is an effective treatment

Question 20

What is the endemic area or source of Naegleria fowleri

Answer 20

• in the soil at the bottom of lakes
• swimming
• other water activities
• Neti pot

buzz words: altered sense of taste and smell

sympoms:

• PAM (Primary Amebic Meningoencephalitis)
• nuchal rigidity (stiff neck)

-don’t confuse with meningitis - similar symptoms

Question 21

How is Naegleria fowleri transmitted?

Answer 21

contact with the nasal mucosa!
(unique mode of transmission - good for differentiating on test)
-likes to diffuse into brain
-can be lethal within a few days

Question 22

How could one diagnose Naegleria fowleri?

Answer 22

CSF sample! - cloudy sample is positive (ameba and RBCs are present)

Question 23

What is the endemic area or source of Enterobius Vermicularis?

Answer 23

a kids asshole?

buzz words: Itchy anus at night and scotch tape test

Question 24

What are helminths?

Answer 24

WORMS!

-pin worms are the most common parasitic worm infection (children get infected)

Question 25

What is the endemic area or source of Dracunculus medinesis?

Answer 25

Asia
Africa
*NOT FOUND IN US

buzz words: vesicle or large blister on the skin