Exam II

Fish 424 (Fish Health)

April 16th, 2003

Please read each question carefully and provide complete answers. Good luck! (100 pts total)

  1. (10 pts) Scott Williams discussed the use of family selection in commercial aquaculture. What two diseases has Clear Springs Foods been attempting to select resistant rainbow trout strains for. Explain what the key feature is that eliminates the risk of selecting fish that could be potential carriers of an infection?
  1. Match the items in the following list to the appropriate fish disease. Place the letter associated with the pathogen or symptom in the blank corresponding to the disease in which it causes. (2 pts each)

a. Aeromonas salmonicida___ Coldwater disease (CWD)

b. Yersinia ruckeri___ Columnaris

c. Renibacterium salmoninarum___ Bacterial gill disease

d. Rhabdovirus___ Furunculosis

e. Necrosis of pancreatic acinar cells___ Bacterial kidney disease (BKD)

f. Flavobacterium branchiophilum___ Motile Aeromonas septicemia

g. virus targets epithelial tissues___ WSIV

h. Flavobacterium psychrophilum___ (IPN)

i. “haystack” formation___ Mycobacteriosis

j. A. hydrophila___ Enteric redmouth (ERM)

k. Zoonotic___ Infectious hematopoietic necrosis (IHN)

  1. (2 pts) Which clinical symptom is caused by a deficiency in the vitamin niacin?
  2. cataracts
  3. broken back syndrome
  4. brown blood disease
  5. sunburn
  6. None of the above
  1. (2 pts) Which fish disease was the first commercial aquaculture vaccine/bacterin developed against?
  2. Enteric Redmouth
  3. Furunculosis
  4. Coldwater disease
  5. Infectious hematopoietic necrosis
  6. Bacterial Kidney disease
  1. (2 pts) ______poisoning is caused by feeding moldy feed and results in acute mortalities and large tumors forming in the livers of affected fish.
  1. (2 pts) (True or False) An attenuated virus can often be produced by multiple passages in tissue culture.
  1. (2 pts) Name 2 concerns over developing attenuated viral vaccines.
  1. (2 pts) The number one disease problem in Catfish aquaculture is causes by what pathogen?
  1. (2 pts) Some fish pathogens are considered zoonotic. Name one, and describe how a person may become infected with it.
  1. (2 pts) What do many bacteria produce that can cause direct damage to host cells and tissues?
  1. (2 pts) What parasite products are considered toxic and can cause host cell and tissue damage?
  1. (5 pts) Ben LaFrentz discussed the immune response of fish to Flavobacterium psychrophilum. Explain how passive immunization was used to determine the importance of antibodies in protection of fish from coldwater disease.
  1. (8 pts) What occurs during the replication process of IHNV that helps it partially evade the host’s immune system? During this process, what component (antigen) is capable of being recognized by the host and is important for stimulating a protective immune response?
  1. (2 pts) If a diet were deficient in vitamin C, what clinical symptoms would you expect to see in fish.
  1. (4 pts) Lymphocytes are made up of 2 major cell types. 1) Name these 2 cell types, and 2) name the organs that each cell type is derived from.
  1. (2 pts) During the immune response, cells work together to produce an immune response to a pathogen/antigen. What important molecules are produced and found in the serum as a result?
  2. Cytokines/lymphokines
  3. Antibodies/Immunoglobulins
  4. Complement proteins
  5. All of the above
  6. None of the above
  1. (3 pts) Define “CPE” and explain why is it important for disease diagnostics?
  1. (5 pts) Draw the life cycle for Myxobolus cerebralis.
  1. (3 pts) Why are brown trout less susceptible to whirling disease than many other salmonids?
  1. (3 pts) Myxobolus cerebralis spores can survive outside the host for up to 30 years. What can anglers do to help limit the spread of these spores between water sources?
  1. (15 pts) Fish hatcheries rearing chinook salmon in the Pacific Northwest have implemented 3 major steps to reduce the incidence and impact of Bacterial Kidney disease. List these 3 things and explain what the significance of each is.

Extra credit

(2 pt) What is a virion?

(2 pts) Describe how a granuloma is formed and name a disease where this symptom is common.