28, 29, 30: infectious pregnancy loss Flashcards
3 mechanisms of infectious pregnancy loss:
- severe maternal illness -> luteolysis -> abortion in species in which CL solely responsible for preg maintenance at time of insult
- placentitis fetal infection -> fetal death
- placentitis -> inadequate nutritional support, hypoxia -> fetal death
t/f
many abortigenic organisms in domestic animals are zoonotic
true
what is the key to submission of tissues for histopath evaluation?
- include comprehensive history with the submission
- weights of fetus(es) and afterbirths if all are NOT submitted
- all abortuses should be submitted
- if outbreak: submit samples from several animals
why are fetal membranes important for diagnostics?
what parts of the fetal membranes should be submitted?
- route of infection of fetus in most cases
- include aspirate of fetal fluids if any remain
- slab sections from different portions of the afterbirth [fresh and formalin fixed]
- include areas of gross abnormalities
what samples from dam are important to submit?
- blood samples
- swab from vagina or uterus
[bitch vagina and mare uterus] - feed and water samples as indicated
what types of infections post most significant risk to commercial operations?
VIRAL INFECTIONS
what effects do viruses have on swine pregnancy?
- preg loss d/t direct effects upon embryo/fetus (MC)
- repro consequence dictated by immune status of the dam to the offending virus
t/f
many viruses are endemic to swine herds
true
t/f
management of swine dzz is based on eradicating the presence of all virus on the farms
false
live with low virus levels - manage the herd / dzz to decrease to likelihood of mass losses
in the mare, bacT cause what types of infection?
- placentitis: ascending or focal non-ascending
- leptospirosis: descending
what does viral infection cause in pregnancy of the mare?
placentitis is extension of fetal viremia
t/f
in the mare, most organisms do not cause systemic dz
true
what signs of abortion do organisms cause in the mare typically?
premature mammary development
vulvar discharge
what predisposes a mare to ascending infections?
- anatomic abnormalities: poor perineal conformation or cervical incompetency
- bacT, including commensal flora that contaminate the chorion overlying the cervical os
what is the origin and progression of fungal infections in the mare?
ascending - progresses to diffuse -> placental insufficienty -> fetal growth retardation -> abortion
what fungi are MC to cause placnetitis in the mare?
- Aspergillus fumigatus ***
- Mucor spp
what are premonitory c/s in the mare with a fungal infection?
- thick, tenacious brown vulvar discharge
- premature mammary development in several days
- sporadic, MC in stabled mares
what does placentitis in the mare caused by fungus cause?
at what time?
abortion at 8-11 mos
t/f
fungal dermatitis is common in equine fetuses affected by fungus
false
fungal dermatitis is NOT common
what % of pregnancy loss in mare is due to fungus?
less than 10%
what is MC bacT etiology that causes placentitis in mare?
where is the bacT from?
ascending or descending?
Streptococcus equi subspecies zooepidemicus
commensal organism in mare vagina
ascending infection
in the mare, what is common bacT that causes non ascending, focal mucoid discharge during placentitis?
nocardioform actinomycete group of organimsms
what does an ascending bacT infection in mare look like on the placenta?
- infection of chorion is focal at the area overlying the internal cervical os (cervical star)
t/f
ascending bacT infection in the mare is likely to cause abortion d/t placental insufficiency
false
abortion likely d/t fetal septicemia or endotoxemia OR placental malfunction -> endo abnormalities mimicking changes occurring at the time or normal parturition
typically where do focal non ascending bacT affect the uterus of the mare?
at the base of the uterine horn
NOT in the cervical star
how is Dx of ascending bacT placentitis in the mare made?
- transrectal u/s
- transabdominal u/s
what is seen on transrectal u/s in mare with ascending bacT placentitis?
separation of chorioallantois from endometrium
thickening of the utero placental unit: 8 mos preg, no later than 8 mm
exudate in the vagina
what is seen on transabdominal u/s on mare with ascending bacT placentitis?
thickening and separation as above
confirmation of live/dead fetus
fetal heart rate
in case of placentitis in mare, what occurs to prod of 5a pregnanes?
p4, prod by fetal adrenal and converted to 5a pregnanes in placenta, so 5a pregnanes inc with placentitis d/t fetal stress
in case of placentitis in mare, what occurs to prod of e2?
e2 prod, from the fetal gonads, is converted to estrone sulfate in placenta, decreases faster than normal
normally, what triggers prepartum mammary development?
fetal stress => adrenal glucocorticoids, inc p4 and dec e2
mares w premature mammary dev have what hormone profile
why?
high p4
low e2
induced by fetal distress d/t placental dz
what triggers milk let down when a mare “waxes” and “runs milk”?
sudden decreased p4
in abnormal preg, what is the hormone profile?
- fetal septicemia - inc p4 and dec e2 - fetus dies - dec p4 to 0 and ABORTION
when mammary development begins occurring, what is the hormone profile?
e2 dec and p4 inc
what causes the abortion in a mare to occur, after premature udder enlargement?
precipitous dec in p4
t/f
abortion can be averted by replacement hormone therapy in the mare
true
what is the Tx of ascending bacT placentitis in the mare?
abx - TMS, pen, gentamicin anti inflammatory - banamine, but pentoxifylline vit E eoxgenous p4 - altrenogest monitor - confirm that fetus remains alive
t/f
leptospirosis is zoonotic?
true
what causes leptospirosis, which is assoc w abortion in mares?
Leptospira interrogans, serovar Pomona type Kennewicki
abortion caused by leptospirosis is ascending or descending infection?
descending - hematogenous spread from mare to placenta
where do lepto organisms localize to in mare?
where does vasculitis occur?
- to repro tract and damages placental vasculature
- organism precipitates vasculitis on allantoic side of the chorion
what repro manifestations occur in the horse?
- resorption of embryo once implantation has occurred
- abortion at 6-9 mos
- still birth
- birth of weak neonates
what lesions are seen in mare with lepto?
- fetal mem lesions are diffuse
- chorion necrotic: thickened, brown, mucoid
what lesions are seen in fetus with lepto?
- enlarged liver, less often kidneys
- yellow discoloration
- hemorrhage
what is epidemiology of mares with lepto?
- sporadic with outbreaks
how is lepto diagnosed?
- based on lesions in abortus
- pos culture, PCR, fetal serology, visualization of bacT
px lepto in horses?
dec stocking density
do NOT feed on ground
where does Equine viral arteritis virus replicate?
endothelium
macros
epithelium
myometrium
t/f
equine viral arteritis virus can survive in frozen semen
true
t/f
morbidity and mortality are both high for EVA?
true
what breeds of horses have highest rates of exposure / infection of EVA?
standardbreds (80%)
and warm bloods
what % of unvaccinated horses in USA are seropositive for EVA?
2%
EVA transmission?
efficient transmission?
- respiratory
- venereal or contaminated semen
- fomites
- contact w abortus
- transplacental
yes - 85%
c/s of EVA?
MC subclin or mild
resp signs, nasal discharge
fever
malaise
how long is EVA shed in resp secretions?
14 days
severe EVA manifests how reproductively?
- transient subfertility in acutely infected stallions d/t fever
- fertility NOT dec in chronic carriers
- preg loss/abortion
t/f
EVA causes dec semen quality
false
rate of abortion in mares with EVA?
70%
when does abortion occur in mares w EVA?
3-10 mos gestation
what are gross lesions on fetus and membranes with EVA infection?
none - fetus and membranes are autolyzed w no pathognonomic gross lesions
t/f
in a horse with EVA, she will make a premature udder to signal the abortion
false
NO premature dev - she drops the fetus w/o signs
what is the carrier % of EVA in stallions?
30-35%
where is the EAV virus loc in the male repro truct?
how is it maintained there?
testosterone dependent maintenance of virus
in ampullae
t/f
carrier stallions for EAV will shed virus continually
true
how might a stallion be cured of EAV?
geld him - then no T so virus does not survive
how to detect carrier status in a stallion?
seropositivity by serum neutralization in absence of vaccination
virus isolation from sperm rich fraction of ejaculate
3 wks for test result
how is EVA Tx and managed in acute cases?
- isolation
- symptomatic, supportive care - nasids and diuretics
- neonates suffering from fulminating pneumonia usually succumb quickly
- vacc of exposed and at risk animals
what animals cannot be vacc for EAV?
pregnant mares
foals less than 6 wks
in carrier stallions, how is EVA Tx and managed?
- castrate to cure
- down regulating T => NOT a good idea
- double sperm processing technique
- pre breeding vacc and isolation of mares bred to EAV shedder
t/f
a single sample of serum is sufficient to determine a mare’s EAV status
false
if pos, she may have been vaccinated
what is best test to see if mare is pos for EAV?
virus isolation from nasopharyngeal or conjunctival swabs
IHC to viral proteins in aborted fetus
what vacc is available for EAV?
how should it be administered?
MLV
induces strong long lasting immunity similar to nat’l infection
confirm sero negative before giving vaccine
confirm subsequent seroconversion
in MO, need state vet permission to give the vaccine
colts: 6-12 mos than annually
breeding stallions: annually 4 wks prior to beginning of season
stallion management to px / monitor EAV status in unvaccinated sero negative animal?
serology annually
if pos: virus isolation on semen
how to manage stallion with sero positive EAV and unknown vacc hx?
virus isolation on semen
how to manage stallions for breeding related to EAV?
TEST
vacc or survey each year
how is EHV-1 transmitted?
respiratory secretions
fomites
where does EHV-1 replicate?
in resp epi
endo of uterus and CNS
c/s of EHV-1?
inapparent infection
resp dz
abortion
neurologic dz
t/f
abortive and neuro forms of EHV-1 usually occur concurrently
false - typically they are mutually exclusive and NOT seen together
what is mech of EHV-1 abortion?
when in gestation?
viral trans location into placental vasculature -> fetal viremia -> infection of fetal endo cells -> fetal vasculitis -> fetal death
final 1/3 of gestation
t/f
during EHV-1 abortion, mare is often ostensibly ill and develops a premature udder
false
mare often NOT ostensibly ill and does NOT drop a premature udder
what is status of abortus in EHV-1 abortion of the mare?
very fresh
often contained w/in membranes
dx of EHV-1?
submit abortus - virus isolation for intranuclear inclusion bodies in fetal lung, liver and thymus
paired serology: rapid titer increase
EHV-1 vaccine?
yes - killed product for pregnant mares
manage mares to dec EHV-1?
separate preg mares from other stock
vaccinate
maintain preg mares in small groups to dec impact if outbreak
t/f
the doe has a high incidence of abortion relative to other farm animals
true
in doe, what etiology is 1* cause of abortions?
bacT and protozoa
over virus
in doe, abortion occurs d/t what processes?
placentitis -> fetal infection
severe maternal dz -> luteolysis
t/f
most etiologies of abortion in doe are not zoonotic
false
most are zoonotic
in the ewe, are most etiologies of abortions zoonotic?
yes
what is an acceptable background rate of abortions in ewe?
2%
what rate of abortions in ewes causes concern?
over 5%
about what % of abortions in cattle are d/t bacT?
about 55%
what are 2 factors in cattle pregnancy that make fetus and placenta susceptible to bacT infection?
- immature fetal immune sys
- immuno-suppression at fetal-maternal jxn of placenta
in cattle, how are mycotic etiologies of abortion spread?
inhalation and ingestion
what is etiology of mycotic abortion in cattle?
sporadic occurrences
what is the offending organism MC in mycotic abortion in cattle?
aspergillus fumigatus
moreriella wolfi
c/s of mycotic abortion in cattle?
severe placentitis
fungal dermatitis in fetus
post abortion pneumonia and death in the dam in morteriella wolfi
dx of mycotic abortion?
isolate organism
demonstrate fungal hyphae
what organism causes leptospirosis in south american camelids?
L. interrogans serotype grippotyphosa
source of lepto infection in camelids?
livestock
contaminated environment
urine of chronic shedders in camelid herd
repro consequences of lepto in camelids?
infertility/subfertility
abortion
stillbirth
maybe retained fetal membranes
dx lepto in camelids?
organism in urine or tissues via FA, PCR, silver stain
serology: acute and convalescent titers 14 days aprat
px lepto in camelids?
limit contact w rodents and wildlife
vacc in contact dogs
vacc in endemic areas and where risk factors exist
tx lepto in camelids?
abx (pen) to chronic shedders
repro consequences of BVDV in camelids?
early fetal loss
abortion
stillbirth
birth of persistently infected (PI) crias
herd testing for BVDV in camelids?
blood samples for PCR and serology
if pos test results, retest those individuals in 3-4 wks
t/f
vacc against BVDV using cattle products is an effective preventative measure to take in BVDV?
false
MC cause of canine abortion?
mechanisms?
infectious agents
- direct infection of fetus via viremia or bacteremia
- placentitis -> impaired feto-maternal exchange of nutrients, wastes, etc
signs in preg bitch that suggest infectious agent that might affect the fetuses and placentas?
inappetance
depression
fever
vomit, diarrhea
t/f
relatively severe systemic illness that does not directly involve repro tract/illness/placentae in a preg bitch often do result in preg loss
false
systemic dz that makes her sick is unlikely to cause abortion
trans of brucella canis in dog?
shed in urine, vaginal discharge, aborted tissue, semen
ingestion, inhalation, venereal routes
c/s of brucella in bitch?
stud dog: epididymitis, scrotal dermatitis
bitch: late term abortion, embryonic mortality, resorption
general: lymphadenitis, discospondylitis, uveitis
no symptoms
findings of brucella in aborted fetus?
partial autolysis
lesions consistent w generalized bacT infections -> sub Q edema, degenerative lesion of liver/spleen/kidney/SI
serosaanguinous to brown vulvar discharge up to 6 wks post partum
definitive dx of brucella in a bitch?
isolate organism from blood, lnn, infected tissues or discharges [gold standard]
most accurate during first 8 wks post infection
what type of serology test is used as a screening tool for brucella in bitches?
- rapid slide/card agglutination test - but cross reactivity w cell wall Ags of other spp
enhance test w addition of 2-ME
if pos: add another test method to conform
if neg: repeat in 2-6 wks to r/o early infection
what test detects cytoplasmic Ag of brucella canis?
what does a pos test indicate?
ADIG - agar gell immunodiffusion test
positive is condidered confirmatory
suggested Tx and management?
castrate / ovariohysterectomy
abx
BEST OPTION: euthanasia
why is euthanisa the best option in brucella positive dog?
high zoonotic risk
management of brucella outbreak in dog breeding kennel?
- confirm dz pos
- quarantine kennel
- ID and cull sources of infection: repeat monthly testing
- implement biosecurity and testing measures to px additional outbreaks
state vet runs the show!
what virus in the bitch is endemic to many colonies but can lead to preg loss?
canine herpes virus 1a
trans of canine herpes virus 1a?
via direct contact w respiratory or genital secretions
mech of offspring infection in canine herpes virus 1a?
- transplacental: fetal viremia -> early fetal death w resorption, abortion, stillburth
- latent virus re activated in preg bitch: shedding in genital secretions -> pups infected at birth
what are possible outcomes of puppies from bitches with canine herpes virus 1a?
- weak neonates - fading puppies
- inc neonatal mortality in 1st wk
- survive to become carriers
tx of canine herpes virus 1a?
supportive care
anti virals are expensive and not effective
px canine herpes virus 1 a infection in puppies?
- keep puppies warm - low body temp favors viral rep in puppies
- isolate aborting bitches
- dispose of abortuses appropriately
- no vacc available in US
dx canine herpes virus 1a?
IFA demonstration of viral Ag or intra nuclear inclusion bodies in fetal and/or placental tissues
MC etiology classification of abortion in queen?
viral
