Arteriviridae Flashcards
What is the only genus of the family Arterivirdae?
Arterivirus
Where do arteriviruses have a tropism for?
Vascular endothelium
T/F: Arteriviruses are not host restricted
FALSE
Highly host restricted
Where in the body do arteriviruses replicate?
MACROPHAGES –> then move to vascular endothelium
How do arteriviruses evade the immune system?
Inhibiting interferons (IFN)
Where in the cell do arteriviruses replicate?
Cytoplasm
Arteriviruses are _________ stranded, _______ sense RNA
Single stranded
positive sense
What envelope proteins are receptor binding proteins for arterivirues?
GP2, GP3, GP4
What is the function of GP5 (glycoprotein) in arteriviruses, why is that important?
GP5 induces neutralizing antibodies
**this is what you look for diagnostically
What receptor does PRRSV bind to?
CD163
heparin sulfate and sialoadhesions
What does Equine Arteritis virus cause?
Equine viral arteritis
Who is the main culprit for spreading EAV? By which mode of transmission?
Non-symptomatic stallions - venereal
*also transmitted via aerosol
What are the clinical signs of EAV
*many infections are asymptomatic
Fever at onset
Depression, excessive lacrimation and conjunctivitis, nasal discharge, *urticarial of the neck, edema of the eyes –> progressing back to chest, abdomen, and limbs
Where do persistent EAV infections reside?
Reproductive system
**abortion in females (between 3-10 months gestation)
T/F: EAV will affect the smooth muscle of arteries and the uterine wall - causing abortions.
TRUE
What dx method(s) are used to dx EAV?
RT-PCR and ELISA
T/F: There is no vaccine available for EAV
FLASE
There are attenuated and inactivated vax, although not many horses are vaccinated for EAV. **Mares should be vaccinated prior to pregnancy
What is PRRSV?
Porcine reproductive and respiratory syndrome virus
Where is this virus active?
Present worldwide in swine breeding countries
How long do infected pigs shed PRRSV?
at least 60 days
Who are the most susceptible to PRRSV?
Gilts - young sows
What clinical signs are seen in gilts with PRRSV?
Anorexia, fever, lethargy, depression
**Respiratory distress **Cyanosis starting at the ears and working backwards along the body,
then repro issues: still births, mummification, abortions, if piglets are born they die within days
What is the progression of PRRSV?
Primary infection begins in the upper respiratory system –> moves to lymphoid tissue –> crosses placenta and replicated within the umbilical cord
What diagnostics are performed when you suspect PRRSV?
virus isolation FAT - flurescent AB test Immunohistochemistry PCR ELISA
When and what samples should be collected for PRRSV testing?
Collect blood samples at peak viremia - when pigs are febrile.
Can also take samples at necropsy from adults and fetus (any tissue/organs that appear to be affected or abnormal)
What are the four main methods to control PRRSV?
- Vaccines - killed and live available (must be done before breeding)
- Intentional whole herd infection - controversial/risky. Must use a LOW virulence strain of infection. Pigs that will be left with a good immunity to all strains of PRRSV
- Aggressive acclimation of replacement breeding stock: quarantine (60-90d) all new animals and have multiple negative dx tests before introduction to the herd
- Cut your losses and repopulate with a new healthy stock
T/F: it is easier to control PRRSV in a small herd population
TRUE
