chytrid fungus

Question 1

chytrid fungus

Answer 1

• fungus
• Bd
• chytridiomycosis

Question 2

CF mode of transmission

Answer 2

• direct contacts from frog to frog
• indirect when frog skin comes into contact with water containing fungus spores or water facilitated transport
• water borne fungus that only attacks amphibians

Question 3

CF geographical distribution

Answer 3

• worldwide spread via pet trade and frog meat trade
• coast of australia
• south west of WA

Question 4

CF impact on host / symptoms

Answer 4

• very infectious
• high mortality in wild and captive populations
• very difficult to remove
• normally frog skin is thin and permeable allowing for O2 , electrolytes and water to diffuse in and out
• Bd unspools the protein and causes a build up of keratin and thickens the skin
• causes anorexia, lethargy and abnormal posture with hind legs extended
• cardiac arrest and death
• Bd is carried by tadpoles and damages their keratin in the mouth leading to eating difficulties and indirectly causing slow growth and death
• restrict movement of frog

Question 5

CF economic importance

Answer 5

• kills 80% of amphibians in 1 year in good conditions
• decreases biodiversity and damages food chains
• the cost of research for identifying and preventing it
• more then 4 species extinction
• decline of more then 10 species
• species have become endangered
• frogs help public health by eating mosquitos

Question 6

CF diagnosis

Answer 6

• lab testing is required
• behavioral change: reluctant to move, sitting unprotected during the day
  skin scrapes:
• fastest, cheapest and easiest
• need experienced scientist to prepare the slides and identify Bd cells
  tissue strains:
• detects light infections
• can use small samples eg toe clippings
  PCR analysts

Question 7

CF prevention

Answer 7

captive breeding and restocking programs
- restock species that are endangered
research and monitoring
- monitor fungus distribution
- develop diagnostic tools
- research spread factors
quarantine
- stop the movement of frogs
disease control
- only touch frogs when necessary 
- stop pet trade

Question 8

CF life cycle

Answer 8

1. zoospores:
   - live in moist environment
   - free living flagella swim short distances in water to frog skin
   - it enters a skin cell and encysts inside
   - then becomes a zoosporangium
2. zoosporangium
   - grow on frog skin and start producing zoospores
   - mature zoospores are released into the external environment
   - lives in moist areas until they find a host