Amphibian Diseases

Question 1

Discuss the main characteristics of amphibians (4)

Answer 1

• respire through skin
• 3-chambered heart (2 atria & 1 ventricle)
• adults = carniverous, young = herbiverous
• lay eggs (in water)

Question 2

Discuss the housing and nutritional requirements of amphibians.

Answer 2

Housing
- aquarium, terrarium, vivarium
- light cycle (day/night influences metabolism)

Nutrition
- Adults: high-protein; insects
- Larval: herbivorous
- Improper nutrition predisposes to several conditions

Question 3

What is the primary stressor of amphibians? How can it be controlled?

Answer 3

Water quality!!
- ammonia-nitrite-nitrate toxicities
- temp., pH, DO2
- imparied osmoregulation due to skin/gill irritation/hyperplasia

CONTROL via water filtration & sanitiation

Question 4

What is Red-Leg Syndrome

Answer 4

Aeromonas hydrophilia -> invades skin 2º to poor water quality or trauma

Question 5

What is the main lesion of Mycobacteriosis?

Answer 5

skin ulcerations

Question 6

Describe the lesions of Saprolegniasis

Answer 6

white, cottony growths on skin

Question 7

Describe lesions of Chromomycosis

Answer 7

Disseminated, black granulomas on skin + internal organs

Question 8

What disease has up to 100% mortality rate with sudden death in amphibians worldwide?

Answer 8

Chytridiomycosis

“Chytrid Fungus”

Question 9

Pathogenesis of chytridiomycosis

Answer 9

opportunistic zoospore of keratin within epidermis (adults) that fatally disrupts osmoregulation & gas exchange of skin

hyperkeratosis, epidermal hyperplasia, ulceration, edema

Question 10

How to dx Chytridiomycosis (3)

Answer 10

ID fungal sporangia in wet mount, histology, or DNA on PCR

Question 11

Cutaneous infection of frogs that involves migration of nematode agent, causing skin sloughing, irritation and excessive mucus.

Answer 11

Capillariasis

Question 12

What disease is associated with seasonal change and causes renal adenocarcinoma?

Answer 12

Lucke’s tumor: Ranin Herpesvirus 1

eggs & young most susceptible

Question 13

Emerging virus of amphibians in both wild & captivity causing mass mortalities

Answer 13

Iridoviruses
- erythema & hemorrhage of mouth & legs
- skin lesions

Question 14

Describe 4 main clinical signs of illness in amphibians.

Answer 14

• skin ulcerations
• lethargy
• sloughing of skin
• erythema

Question 15

List the most important zoonotic diseases of amphibians (3)

Answer 15

1. Aeromonas spp.
2. Mycobacterium spp.
3. Chromomycotic sp.