Swine: Viruses of Reproductive System
PRRS (persistent revenue reduction syndrome virus)
porcine parvovirus
Aujeszky's Disease/pseudorabies herpesvirus
swine reproduction
114d gestation
epitheliochorial placenta
Ig transfer is 100% colostrum
no Ig cross placenta
viruses can cross it though
clinical signs
conception failure
late return to service
decreased farrowing rate
abortion
mummification
stillbirth
weak neonate
neonatal death
causes "SMEDI"
Stillbirth
Mummification
Embryonic Death
Infertility
signs
neonatal death
decreased male fertility
most important indictor for transplacental infection
death b/w 35-110d gestation
qualities
hemorrhagic
edematous
dehydrated
dried green dark body
sunken eyes
CR length
type I
placentitis
fetal infection
PRRS
pseudorabies
type II
systemic illnes with high fever
no placental or fetal infection
normal appearance
lungs don't float
no milk in stomach
mummies
greater than 1.0/litter needs to be investigated
if present, infectious cause
if not present, non-infectious cause
necropsy kidney, liver, blood
(during birth) intrapartum deaths
non-infectious
management problems
attended farrowing
nutritional
faciities
farrowing crate
temperature
CO
individual sow
parity
sow size
piglet size
birth order
gestation length
farrowing duration interval b/w piglets
prepartum deaths
infectious
sytemic pathogens
Erysipelas
reproductive pathogens
PRV
PPV
lepto
diagnosis
frustrating
agent usually no longer present at time of repro failure
condition of fetuses may be poor
divided into 2 major classes
primary infection
secondary repro effects
main cause 60-70% of the time
30-40% problems
characteristics
nonenveloped
stable in environment
need S-phase rapidly dividing cells
agglutinate blood
tolerate wide pH range
tolerate temp range
characteristics
enveloped
surface glycoproteins essential for infection
latent
"Herpes is forever"
characteristics
enveloped
alveolar macrophage tropism
spreads to lymphoid tissues
prolonged infection (~250d)
virus modulates host innate resposne
persistent viremia
neutralizing Abs appear after* viremia decline
worldwide
mutation common
pregnant sows are indicators of virus introduction
easily transmitted
herd immunity influence
sows are clinically normal
fetuses dad at different stage of development
small litter size
abortion
clinical signs
disease is age dependent
growing pigs
respiratory disease
CNS disease
reproductive
abortions
mummies
stillborns
clinical signs
respiratory disease at all ages
most severe in growing pigs
reproductive disease in pregnant sows
worst at third trimester
abortion
stillbirth
mummies
weak piglets
high preweaning mortality
premature farrowing
transmission
oral
intranasal
percutaneous
sexual
transmission
fecal-oral
semen
fomites
transmission
shedding starts 2-5d after infection
secretions
nasal
vaginal
oral
direct contact
fomites
semen
consumption of infected tissue
transplacental
arthropod (?)
aerosol
unstable in environment
pathogenesis
sheeding 2-5d after infection
latency
dexamethosone induces recrudescence
pathogenesis
fetus
susceptible in first half of gestation
10-14d required to infect
fetuses usually survive transplacental infectious after mid-gestation
infection can spread between fetuses
reproductive failures
first trimester
reabsorb fetuses
return to estrus
second and third trimester
abortion
stillborn pigs
liveborn and infected
abortion without fetal infection
"flu-like"
sudden death in other farm animas 🐶🐱
off-feed
adults
reduced appetite
fever
premature farrowing and abortion
10% deaths in sows
ataxia
circling
falling to one side
serology
fetuses
necropsy
placenta
single samples
may be convalescent serum in fetuses
diagnosis
uterus examination for fetuses
submit <17cm fetuses for necropsy
lung FA
virus isolation
PCR
serology
in fetuses, thoracic fluid
HI test (?)
most sows and gilts are immune
colostral Abs decline after 3-6mo
diagnosis
detecting virus
serology
ELISA
DIVA
virus isolation from bodily secretions or lymphoid issue
IFA
PCR
SN (?)
colostral Abs if under 4mo
diagnosis
samples
serum
bodily fluids
lymphoid tissues
virus detection
qrt-pcr
virus isolation
Ag detection
IFA
control and prevention
vaccine
random serology of breeding age gilts
problem if >20% seronegative
check HI (?) rise after vaccination
newly introduced breeding stock
seronegative herd goal
new farm
young gilts with passive Abs only
no natural infection source
biosecurity
young gilts and boars only
longer interval of breeding group
types
autogenous
modified live
killed
risk of persistence and transmission
disinfection
nursery depopulation
control
vaccination
MLV
DIVA needed
intranasal
sow
neonate
quarterly