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

Screen Shot 2020-10-10 at 4.53.13 PM

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