Family: Circoviridae

Question 1

What type of DNA genomes do the genus Circovirus and genus Gyrovius have?

Answer 1

Circovirus: circular, single stranded ambisese (+ and -) DNA
Gyrovirus: circular, single stranded negative sense DNA

Question 2

Where does virus replication occur?

Where does DNA replication occur?

Answer 2

Virus replication occurs in actively dividing cells.

DNA replication occurs in the nucleus.

Question 3

What is a common name of Porcine circovirus 2?

Answer 3

Post-weaning multisystemic wasting syndrome (PMWS)

Question 4

Transmission of Porcine Circovirus 2

Answer 4

Fecal oral is the most common method of spread
Virus is found in all secretions (feces, urine, nasal)
Vertical transmission 9transplacental)

Question 5

Pathogenesis of Porcine Circovirus 2

Answer 5

Characterized by individual to coalescing foci of granulomatous inflammation in lymphoid tissue, lungs, liver, kidney, heart, and intestines

Question 6

What type of inclusion bodies are found due to Porcine Circovirus 2?

Answer 6

Botryoid (grape-like) intra-cytoplasmic inclusion bodies in virus infected macrophages

Question 7

Effects of transplacental infection of Porcine Circovirus 2

Answer 7

Infection during 1st and 2nd trimesters = fetal death and resorption, or aborted fetuses with severe cardiac congestion

Infection during last trimester = minimal effect on fetuses

Question 8

Co-infections that occur with Porcine Circovirus 2

Answer 8

1. Porcine Parvovirus - aborted, mummified, and stillborn fetuses
2. Porcine Arterivirus (PRRs) - interstitial pneumonia, aborted fetuses
3. Mycoplasma Hyopneumoniae - enzootic pneumonia of swine->chronic bronchopneumonia

Question 9

Vaccination for Porcine Circovirus 2

Answer 9

Chimeric vaccines - use non-pathogenic Porcine Circovirus 1 as a genetic backbone for expression of the immunogenic capsid protein for PCV-2
Piglets - vaccination with either 1 or 2 doses with the 1st does at 3 weeks of age and the 2nd dose 3 weeks later
Sows - vaccination at 2 and 5 weeks antepartum

Question 10

Porcine Dermatitis and Nephropathy Syndrome (PDNs)

Answer 10

Associated with PCV 2

Necrotizing skin lesions, necrotizing vasculitis, necrotizing and fibrinous glomerulonephritis

Question 11

Hosts of Chicken Infectious Anemia

Answer 11

Highly contagious disease of young chickens

Older chickens are more resistant to clinical disease

Question 12

Transmission of Chicken Infectious Anemia

Answer 12

Virus is shed in feces and feather dander
Horizontal transmission - inhalation or oral exposure
Vertical transmission - egg

Question 13

Pathogenesis of Chicken Infectious Anemia

Answer 13

Principal sites of CAV replication are hemocytoblasts in the bone marrow, precursor T cells in the cortex of the thymus, and dividing CD4 and CD8 cells in the spleen
Replication in hemocytoblasts leads to anemia
Replication in T cells causes immunosuppression

Question 14

Diagnosis of Chicken Infectious Anemia

Answer 14

Examination of blood - low PCV; total erythrocyte count will reveal anemia, thrombocytopenia, water blood, and clots slowly

Question 15

Vaccination for Chicken Infectious Anemia

Answer 15

Presence of antibodies in breeders reduces vertical as well as horizontal transmission
Synergism of CAV with other immunosuppressive viruses, so both must be controled