Genitourinary Disease Flashcards
what does porcine reproductive and respiratory syndrome (PRRS) cause?
blue ear: viremia, intravascular macrophages
early farrowing
small litter size, weak piglets
stillbirth, mummification, abortion
what is currently the most economically devastating swine disease in the USA?
porcine reproductive and respiratory syndrome
describe the porcine respiratory and reproductive syndrome virus
arteriviridae
enveloped
highly diverse
+ssRNA
how does porcine respiratory and reproductive syndrome virus enter the body?
enters macrophages and disseminates
replicates in lymphoid tissue
what cells does porcine respiratory and reproductive syndrome virus target?
alveolar macrophages
intravascular macrophages
how does porcine respiratory and reproductive syndrome virus evade the immune system?
inhibits macrophage apoptosis, suppresses interferon
inhibits antibody via decoy epitopes
how is porcine respiratory and reproductive syndrome virus diagnosed?
clinical signs
necropsy
serology
PCR
virus isolation
what are some secondary infections that can infect swine with porcine respiratory and reproductive syndrome?
Actinobacillus pleuropneumonia
Haemophilus parasuis
Streptococcus suis
Mycoplasma hyopneumoniae
how is porcine respiratory and reproductive syndrome transmitted?
direct contact with mucosal surfaces
AI/breeding through infected boar semen
contact with fresh feces/urine
transplacental
why is porcine respiratory and reproductive syndrome hard to get rid of?
endemic within most swine herds
reservoir is carrier swine (persists many months)
shed in nasal secretions, saliva, urine, feces, semen, milk
what is the hallmark of porcine parvovirus (PPV)?
litter with dead fetuses of various sizes
what does porcine parvovirus cause with reproduction?
stillbirths
mummification
early embryonic death
infertility
describe the porcine parvovirus virus
parvoviridae
non-enveloped
ssDNA
very stable
why is porcine parvovirus hard to get rid of?
endemic within most swine herds
reservoirs are carrier swine and contaminated environment
how is porcine parvovirus transmitted?
contact/ingestion via interaction with carriers and environment
who does porcine parvovirus primarily affect?
gilts
naive sows
what cells does porcine parvovirus target?
replicating cells
intestinal progenitor cells
haematopoietic precursor cells
lymphocytes
which viral genome has the highest mutation rate?
ssRNA
when does porcine parvovirus infect the fetus?
15 days after gilt/naive sow is infected
what happens if a fetus <30 days is infected with porcine parvovirus?
fetal resorption
gilt/sow returns to estrus
what is the range of size that covers most viruses?
20-300 nm
some much larger
what happens if a fetus >70 days is infected with porcine parvovirus?
fetus mounts immune response
persistently infected and shed chronically, may be unthrifty
how is an enveloped virus most commonly released from the host cell?
budding
how is porcine parvovirus diagnosed?
clinical signs
PCR
virus isolation
