Mycology: Microsporidia - Part 2

Question 1

Exophilala sp.

Answer 1

• Phylum: Ascomycota
• Order: Chaetothyriales (black yeasts)
• genus of anamorphic fungi
• infects numberous vertebrates (fish, companion animals, humans)
• implicated in causing ‘Saxaphone Lung’ or hypersensitivity pneumonitis (dz contracted by woodwind instrumentalists)

Question 2

Phaeohyphomycosis

Answer 2

• caused by group of dark mycotic infxns caused by dematiaceous fungi (black yeasts or fungi)
• morphologic characteristics in tissue: hyphae, yeast-like cells or combo of these

Question 3

Microspora

Answer 3

• Phylum: Microsporidia
• obligate intracellular parasites
• infect every major animal group
• however, greatest numbers infect arthropods and fish
• related to fungi
• all microsporidia are spore-forming
• ultimate parasites: massively reduced genome sizes with loss of many essential biochem pathways (no turning back!)
• obligate fungal parasites (still opportunistic)

Question 4

generalized mature microsporidian spore

Answer 4

coiled polar filament and lack of mitochondria

Question 5

2 proliferative life cycles

Answer 5

1. sporogony

2. merogony

Question 6

Horizontal transmission

Answer 6

Nosema apis infecting honeybees

• adult bees ingest spores as result of comb cleaning
• infection develops in gut epithelium
• mature spores are released into the bees environment

Question 7

Vertical transmission

Answer 7

• direct transfer of infection from parent to progeny
• infected adult female produces eggs containing parasites
• developing young become infected
• maturation to adults, hosts feminisation

Question 8

Horizontal transmission

Answer 8

muscle-infecting microsporidia of fish and shrimp

• fish and shrimp exposed to spores via gut or gills
• infection develops in host muscle
• mature spores are released into environment upon host death

Question 9

paratenic (transport) host

Answer 9

• microsporidia relies on death of host for propagation

- utilise paratenic host for transmission aka small crustacea

Question 10

Amblyospora spp.

Answer 10

involving more than one host species

Question 11

xenoma

Answer 11

single hypertrophid cell

Question 12

Beko disease

Answer 12

microsporidia infecting trunk muscles of yellowtail in Japan

Question 13

Zebrafish microsporidiosis

Answer 13

• Pseudoloma neurophila
• pathogen: Danio rerio
  
  • infects CNS and muscle
  • advanced infections: emaciation and skeletal deformities

Question 14

Salmon louse

Answer 14

• Lepeophtheirus salmonis

- caligid copepods; SEA LICE

Question 15

Wrasse

Answer 15

biological control for removal of parasitic copepods

Question 16

Desmozoon

Answer 16

• microsporidian human pathogen
• only known natural pathogen to salmon lice
• has potential as a bio control agent

Question 17

Microsporidiosis in dogs and cats primarily caused by:

Answer 17

Encephalitozoon cuniculi