Circoviridae - Circovirus Flashcards
Describe the physiological characteristics of circoviridae.
17-22nm in diameter (small)
Single-stranded DNA genome (circovirus- ambisense DNA, gyrovirus- negative sense DNA)
Virions are 20-25nm, non-enveloped, spherical, with icosahedral symmetry (T=1)
What does Chicken infectious anemia virus have that are less obvious in the other circoviruses?
12 trumpet like structures
Where does replication occur?
Actively dividing cell nucleus
Are virions of circovirus stable?
Yes.
Reisting 60C for 30 minutes and pH of 3-9
What is Post-Weaning multi systemic wasting syndrome?
Caused by porcine circovirus 2
What is the host and age affected by PMWS?
Pigs
4-6 weeks or 2-3 weeks post weaning
Where does PMWS occur?
Worldwide
How is PMWS transmitted?
Fecal-oral (most common)
Found in all secretion
Transplacental (vertical transmission)
Fomites
What do the inclusion bodies of PMWS look like?
“Botryoid” (grape-like) intra-cytoplasmic inclusion bodies in virus infected macrophages.
What cells does PMWS target?
Cardiomyocytes, hepatocytes, and macrophages during fetal life.
Mainly monocytes in early post-natal life.
What is the pathogenesis of PMWS?
Lymphoid depletion and lymphopenial in peripheral blood.
Loss of B-cells and T-cells.
Inhibits IFN-alpha
What happens to pregnant sows infected with PMWS?
During the 1st and 2nd trimesters- fetal death and resorption or aborted fetuses with severe cardiac congestion.
3rd trimester - minimal effects on fetuses
What are the common clinical signs of PMWS?
lethargy, progressive weight loss, cough, dyspnoea, slow growth, lymphadenopathy, diarrhea, skin discoloration, congenital tremors, icterus
How does severe disease and more pronounced lesions with PMWS occur?
Confections with Porcine parvovirus, Porcine reproductive virus, Porcine respiratory virus, SIV, Mycoplasma hyopneumoniae, or a variety of bacteria.
How does enzootic pneumonia of swine occur?
Co-infection of PMWS with Mycoplasma hyopneumoniae