Exotics Top Topics - Reportable Aquatic Diseases

Question 1

what government entity is the main regulator of aquaculture in the united states? what is responsible for global monitoring of reportable diseases?

Answer 1

USA - USDA-APHIS

globally - world organization for animal health (OIE)

Question 2

how many aquatic questions should you count on for the NAVLE?

Answer 2

3 that matter

Question 3

T/F: most of the reportable aquatic diseases have a temperature range & susceptible species that can be used to rule in or rule out any differentials

Answer 3

true

Question 4

what 6 fish diseases are of regulatory concern in both the USA & canada?

Answer 4

1. viral hemorrhagic septicemia
2. infectious hematopoietic necrosis
3. spring viremia of carp
4. epizootic hematopoietic necrosis
5. infectious salmon anemia
6. koi herpes virus

Question 5

what is the classic case presentation of viral hemorrhagic septicemia? what species is it endemic in?

Answer 5

acute hemorrhaging, exophthalmia, ascites, & neuro form with spinning

endemic in salmonids, haddock, & cod in PNW & emerging in great lakes region

Question 6

what is the classic case presentation of infectious hematopoietic necrosis? what species is it endemic in?

Answer 6

lethargy with sporadic bouts of rapid swimming, ascites, protruding vent, fecal casts, & high mortality in fish under 1 year of age

endemic - salmonids in the PNW & alaska & also seen in europe, asia, & western us

Question 7

what is the classic case presentation of spring viremia of carp? what species is it endemic in?

Answer 7

also occurs in aquarium fish, koi, & goldfish - nonspecific signs but may appear similar to a motile aeromonad infection

not in the US since 2007 - seen in china, middle east, eastern europe, & russia

Question 8

what is the classic case presentation of epizootic hematopoietic necrosis? what species is it endemic in?

Answer 8

acutely high death rates, hemorrhage around nares, ataxia in redfin perch > rainbow trout

Question 9

what is the classic case presentation of infectious salmon anemia? what species is it endemic in?

Answer 9

severe anemia, petechiae, ascites

endemic - northeastern US, atlantic canada, norway, & scotland

Question 10

what is the classic case presentation of koi herpes virus? what species is it endemic in?

Answer 10

aquarium fish & koi, goldfish can also be infected but don’t get sick (asymptomatic carriers) - severe patchy gill necrosis, rapid mortalities

sporadic throughout the US in carp & hybrids

Question 11

what 6 fish diseases are reportable in the US only?

Answer 11

1. red sea bream iridoviral disease
2. salmonid alphavirus
3. epizootic ulcerative syndrome
4. gyrodactylus salaris infection
5. tilapia lake virus
6. strains of virulent aeromonas hydrophilia of farmed channel catfish

Question 12

what is the classic case presentation of red sea bream iridoviral disease? where is it seen/endemic in?

Answer 12

severe lethargy, anemia in red sea bream

Question 13

what is the classic case presentation of salmonid alphavirus? where is it seen/endemic in?

Answer 13

pancreas disease or sleeping disease - at necropsy, see necrosis of the heart, skeletal muscles, & exocrine pancreas

not seen in the US - seen in europe

Question 14

what is the classic case presentation of epizootic ulcerative syndrome? where is it seen/endemic in?

Answer 14

mycotic granulomatosis - also seen in aquarium fish - caused by the oomycete aphanomyces invadens (water mold) - deep ulcers with granulomatous reactions

sporadic thoughout US & worldwide

Question 15

what is the classic case presentation of gyrodactylus salaris infection? where is it seen/endemic in?

Answer 15

external parasite that causes huge losses in naive trout & salmon

not seen in US - seen in finland, russia, & a big problem in UK & ireland

Question 16

what is the classic case presentation of tilapia lake virus? where is it seen/endemic in?

Answer 16

non-specific signs of lethargy, loss of appetite, decreased schooling behavior, popeye (exophthalmia), darkening ulcers, & hemorrhages

seen in US, asia, africa, central america, & south america

Question 17

what is the classic case presentation of strains of virulent aeromonas hydrophilia of farmed channel catfish? where is it seen/endemic in?

Answer 17

strain ST251 - phylogenetic differences in between ST251 strains of vAh (hypervirulent Ah) & non-virulent a. hydrophila (non-Ah)

disease caused by vAh is similar to that caused by non-vAh - but differences in disease epidemiology, pathogenesis, & presentation

currently identified in 3 states (arkansas, alabama, & mississippi) & 6 chinese provinces

Question 18

what is the classic case presentation of infectious pancreatic necrosis? where is it seen/endemic in?

Answer 18

skin darkening, swimming in a corkscrew pattern, ataxia, anorexia, & exophthalmia

seen worldwide except for australia & iceland

Question 19

what is the classic case presentation of ceratomyxosis? where is it seen/endemic in?

Answer 19

slow swimming, anorexia, darkening, ascites, erythematous, protruding vent, & exophthalmia

seen in british columbia

Question 20

what is the classic case presentation of whirling disease? where is it seen/endemic in?

Answer 20

fish chase their tails/whirl when startled, skeletal deformities, & darkening of tails/peduncle

seen in US, canada, europe, & south america

Question 21

what is the classic case presentation of white sturgeon iridoviral disease? where is it seen/endemic in?

Answer 21

anorexia, weight loss, erratic swimming, erythema of the belly, swollen pale gills, & death

Question 22

what is the only USDA APHIS reportable monogenean in the US? what is the classic case presentation?

Answer 22

monogenean infections in fish from gyrodactylis salaris salmonid specific monogenean

Question 23

what is the etiology of monogenean infections in fish? how is it diagnosed?

Answer 23

gyrodactylis salaris salmonid specific monogenean

skin scrape or fin & gill biopsy with ID of parasite based on morphology/movement

Question 24

how are monogenean infections in fish treated?

Answer 24

commonly managed by bath/immersion treatment & attention to environmental cleaning, species tolerance, & legal/environmental considerations

formalin, fda approved products, praziquantel, organophosphates, & hydrogen peroxide

freshwater dips for marine species or long-term immersion for euryhaline species

saltwater dips for freshwater species

Question 25

how does treatment differ for gyrodactylids causing monogenean infections in fish?

Answer 25

live-bearing, so killing adults kills juveniles & one treatment should work but may need additional treatment for microenvironments

Question 26

how does treatment differ for dactylogyrids, ancyrocephalids, & capsilids causing monogenean infections in fish?

Answer 26

they are egg layers - focus on environmental management (eggs) so multiple treatments are required to kill emergent, susceptible juvenile stages

Question 27

what is important for reducing the impact/introduction of monogenean infections in fish?

Answer 27

good screening/quarantine/biosecurity practices

Question 28

what 4 fish diseases are reportable in the US only?

Answer 28

1. infectious pancreatic necrosis
2. ceratomyxosis (ceratomyxa shasta)
3. whirling disease - myxobolus cerebralis
4. white sturgeon iridoviral disease

Question 29

what is the lifecycle of monogeneans that cause infections in fish?

Answer 29

direct life cycle (unlike related digenea which requires at least 2 live hosts)