Circoviridae - Gyrovirus Flashcards
What is the common name of the disease caused by Gyrovirus?
Chicken infectious anemia
Who is affected by CAV?
Chickens 2-4 weeks of age.
Older chickens are more resistant to the disease
How is CAV transmitted?
Virus is shed in feces and feather dander.
Horizontal transmission through inhalation or oral exposure
Vertical transmission through egg
Virus can persist on fomites for long periods of time
Where are the principal sites of CAV?
Hemocytoblasts in the bone marrow
Precursor T cells in the cortex of the thymus
CD4 and CD8 cells in the spleen
What causes anemia?
Replication in the hemocytoblasts
What causes immunosuppression?
Replication in T-cells
What causes destruction of infected lymphocytes?
Apoptin protein of CAV induces apoptosis
What is the result of thrombocytopenia?
Watery blood that clots slowly
What are birds infected with CAV susceptible to?
Secondary bacterial and fungal infections
What allows more efficient vertical transmission of the virus?
Replication in the oviduct of the chicken regulated by estrogen
What are the clinical signs of CAV?
Anorexia Lethargy Depression Reduced body weight gain Pale Subcutaneous hemorrhages Skelletal hemorrhages Male muscles
How is anemia defined in chicks?
PCV </= 27
How is CAV diagnosed?
Clinical signs Examine blood for low PCV, thrombocytopenia, appearance of watery blood that clots slowly Necropsy Histopathology PCR
What is the aim of vaccination of CAV?
Protect the progeny from vaccinated breeders from early infections by means of maternally derived antibodies
Who are live vaccines available for?
Antibody-negative breeder flocks before the start of egg production.
