Midterm 1 (supplementary to cheat sheet)

Question 1

Chytrids- BD (fungal)

Answer 1

• BD (name too long)
• amphibian spithelial fungi parasite
• motile zoospores –> adhere to skin –> use sporangia to penetrate into tissue –>thallus
• thalli reproduce asexually - thalli invade deeper tissues (dmg)
• eventually thalli migrate to skin surface –> escape as zoospores

Question 1

Microsporidia

Answer 1

• have unique coil structure
• notable in silk worm industry
• Immunocomp’d = life long diarrhea
• healthy = asympt carriers or self-limiting infection
• spores –> direct pen –> sporoplasm proliferates in cytosol –> burst out
• sporoplasms infect other cells or enter intestinal lumen –> feces –> escape
• some species replicate in PV instead of cytosol, some migrate within host using macrophages

Question 2

myxozoa - Myxobolus cerebralis

Answer 2

• have coiled filament structure –> similar to microsporidia
• infect fish –> spinal deformation –> fish can’t swim –> die
• Round spores reside in fish bone/cartilage –> released when fish decays –> consumed by tubifex worms
• round spore –> worm –> actinospore form –> sex reprod –> released in worm feces
• fish predators (eg birds) = paratenic hosts –> aid in spread

Question 3

cryptococcus neoformans (fungal)

Answer 3

• opportunistic (immunocomp’d patients only)
• spores –> inhaled –> lungs –> asex + coughing
• migrate into blood –> macrophage infection and/or carried to brain (meningoencephalitis)

Question 4

P. destructans - White Nose (fungal)

Answer 4

• white nose fungus
• psychrophilic –> humans = safe
• bat hibernation –> body T drops –> infection
• infection –> wing membranes –> eventually causes wing damage
• bat-bat contact transmission (vector based)
• bat infection –> wakes up the bat –> interrupts hibernation early –> exhaustion –> death
• bats = insectivores –> therefore dead bats = more pests = agri impact

Question 5

ascomycotin - Wheat Blight (fungal)

Answer 5

• infects grains (wheat/corn) –> head-wheat blight
• spores –> stalk + fruiting bodies –> mycotoxins –> crop becomes toxic to consume
• harvest leaves behind stalks –> spores allowed to infect next harvest cycle
• spores spread by rain/wind/weather

Question 6

Cordyceps - zombie fungus

Answer 6

• spores falls on ant –> infection
• mycelia replace ant tissues –> compounds used to influence ant behaviour
• ant crawls on underside of leaf –> bites down to anchor self –> dies upsidedown
• cordyceps fruiting body emerges –> release spores
• new spores fall on other ants

Question 7

modes of transmission

Answer 7

vector
direct penetration
trophic
fecal oral
vertical
sexual/horizontal

Question 8

types of parasite speciation

Answer 8

allopatric - physical separation of populations –> cant interbreed
sympatric - mutation prevents interbreeding
peripheral- host carries population away –> carries populationa way –> no more interbreeding

Question 9

Cophylogeny

Answer 9

• Missing the boat - failure to literally infect the new host sp
• failure to speciate - hosts speciate but parasite doesn’t need to (2 host 1 parasite)
• drowning on arrival - host speciates –> is adapted to prevent infection –> parasite dies off in new host
• host switching (incomplete) - 2 unrelated hosts –> H1 and H2 persist (same parasite)
• host switching w/extinction - 2 unrelated hosts –> H1 extinct, H2 remains (same parasite)
• host switching w/o extinction - 2 unrelated hosts –> h1 extinct, parasite speciated for H2

Question 10

define parasite

Answer 10

an organism living in close association with a host organism which is required for the parasite to complete a stage (or multiple stages) of it’s life cycle. Multiple diff hosts may be required. The parasite feeds off of the host organism, usually causing minimal harm to host but in some cases causing death

Question 11

encounter vs compatibility filter

Answer 11

encounter - does the parasite live in the right env spaces at the right time of day/year to cross paths with a given host

compatibility - can the parasite infect this host? correct morphology/structures? genes for evasion? able to survive inside?

Question 12

African fly belt

Answer 12

infection of bovine –> contaminated meat –> low quality protein
also causes cattle death –> forced to use native relient cattle –> less ahrdy for farm work

less agri production –> diminished community developement (also poorer)

Question 13

tse tse fly

Answer 13

T. brucei
- attracted to blue –> use blue coloured insecticidal nets
- eggs are laid in humid soils –> clear land = sun dried
- wear lighter colour clothing to minimize attraction

Question 14

kissing bugs

Answer 14

T. cruzi
- resides in thatch roofing –> falls on face
- infection with TC requires host to scratch –> aiding infection. vector is not enough
- prevention by raising local wealth –> increase concrete housing
- use pesticides

Question 15

sand flies

Answer 15

Leishmania
- resides in OM rich soils –> impossible to condition the soil
- constant bug repellents + go out when flies are less active

Question 16

mosquitoes

Answer 16

malaria
- insecticidal nets
- indoor sprays
- improvement to diagnostics

Question 17

examples of transmissions

Answer 17

vertical -
sexual - trichomonas vaginalis
fecal oral - giardia
trophic - toxo
direct penetration - I. multifilis
vector - malaria