Toni Christopher

Before We Begin…Some Key Terms Aquaculture: human cultivation of

aquatic plants or animals in controlled environments

Fry: fish children Fingerling: young or small fish Hatchling: newly hatched fish Brood stock: fish used for breeding only Hatchery: pond set aside for hatching

eggs Fry Pond: pond in which fry are raised

and cared for

What is CCVD?

Viral disease specific to Ictalurus Punctatus

Causes hemorrhaging and destroys blood forming tissue in the kidneys

Leads to kidney failure and death Temperature sensitive disease More of a problem in aquaculture

than in wild Why?

External Symptoms

Slowing of feeding activities

Erratic swimming, often spiral

Hyperactivity followed by lethargy

Gathering along sides of ponds hanging vertical and motionless

Swollen abdomen Extension of anus

Bulging Eyes Hemorrhages

Base of fins Abdomen Muscle Tissues Gills occasionally Liver and kidney

Pale gills

Internal Symptoms Clear yellow to blood tinged fluid in

body cavities Digestive tract: yellow fluid and

mucus, no food Pale liver and kidneys Dark spleen Inflammatory cells overrun infected

areas

Susceptibility Varies among strains of catfish Inbred strains: more so Outbred strains: more vigor and

increased resistance Ictalurus furcatus: naturally resistant Channel x blue hybrids: same as

parent channel cat Bullheads, Euro., Afric., and Asian:

resistant Pangasius sp.: unknown

An Important Note About CCVD Temperature Reactive

At 4°C, virus life: ≤ 28 days, mostly dormant At 20°C, symptoms dormant up to 10 days At >25°C, outbreaks typically occur,; virus life: 2

days At 25 - 30°C, symptoms seen 2-3 days after

infection Mortalities near 100% after a week

At >30°C, greatest mortalities in smalls Fish size and the amount of virus the fish are

exposed to play a lesser role

Transmission

Fish to Fish Direct contact with dying/infected fish Virus crosses lining of gills and then

intestines Brood stock to young

Survivors may have dormant virus Passed to young at or around spawning

via semen and eggs

Treatment

No true effective treatments Transmission can be limited by less

feeding Improving water quality and

reducing temp. to < 19°C reduce stress on fish and stops deaths

Control and prevention Avoidance, containment, and stress reduction

Control and prevention Avoidance

No feral fish Quarantine new fish and survivors Do not use survivors as brood stock

Containment Sanitize and disinfect with bleach,

dechlorinated water, and thorough air drying

No cross-contamination Stress reduction

Optimal H2O quality; high dis. O2 lvls.; avoid crowding, low circulation and flow; good nutrition

Resources and Images

http://aquanic.org/publicat/usda_rac/efs/srac/4702fs.pdf