Diseases of the pregnant uterus Flashcards
When does an embryo become a foetus?
When major structures have begun to develop, incomplete organogenesis (about 35-45 days in mare/cow)
How is pregnancy maintained? 4
Immunological tolerance/suppression
Hormonal influences
CL dependency (entire pregnancy - cattle/goat/pig/dog. Early pregnancy: horse, sheep, cat)
Luteolysis: stressors/systemic cytokines
What are 5 mechanisms of emrbyonic/foetal loss?
Failure of zygote to attach to endometrium
Early embryonic loss
Late embryonic loss
Foetal loss (non-viable): placetitis and others
Stillbirth (potentially viable stage of gestation)
What level of loss of zygotes/early embryos is considered normal in most species?
15-30%
What happens in early embryo loss?
Leads to expulsion or reabsorption
Normal or delayed return to oestrous (especially cow)
Often no Dx material available
Chromosomal abnormalities important case
Infections rarer: Ureaplasma spp, Tritrichomonas foetus, Campylobacter spp
Results of foetal death?
Abortion
Stillbirth
Foetus may be retained (mummification, maceration, (emphysema)
What happens if foetus dies in a uniparous animal?
Early gestation –> mummification
Late gestation –> usually abortion
What happens if a foetus dies an a multiparous animal?
If most foetuses die –> generally abortion
If one/a few die –> retention, at parturtion, foetuses surviveing are of different sizes and different degrees of mummification (SMEDI)
What is mummification?
mostly multiparous, mostly sows NO bacterial infection foetal skin withstands autolysis Absorption of placenta/foetal fluids No odour Closed cervix expuslion point varies
CAUSES: genetic, twins (mare), viral (BVD, parvo in sows, canine herpes), protozoa (toxoplasmosis), uterine horn torsion (queen), placental insufficiencies
Dx: not usually possible
Usually no effect on subsequent breeding
What is maceration?
Commonly venereal infection
Foetus –> liquified
Bacterial infection in uterus
Reabsorption (early) or expulsion with purulent exudate
Incomplete if bones have developed
Foetid odour
Common infections: Campylobacter foetus venerealis, Tritrichomonas foetus, non-specific endometrial infections
CONSEQUENCE: often pyometra or endometritis
Perforation of uterine wall by foetal bones possible
What causes foetal emphysema?
putrefactive organisms ascending from vagina (gas-producing organisms, e.g. clostridial)
patent cervix
mostly assocaited iwht dystocia at or near term and incomplete abortion
Putrefation of foetus which distends with foul gas and crepitates
advanced uterine lesions
often fatal due to dam toxaemia
What are the broad causes of abortion?
infectious versus non-infectious
List some infectious causes of abortion
Most species - haematogenous infection (predominantly, except mare) of placenta/foetus - some pathogens have affinity for ReproT: Brucella spp, Chlamydophila spp, Coxiella spp.
Ascending - especially mare
Bacterial and fungal abortions in mares mostly ascending
Venereal infections (Tritrichomonas foetus, Campylobacter foetus venerealis, Ureaplasma spp)
When should you investigate sheep abortion?
If >1-2% ewes are aborting
When should you investigate bovine abortion?
if >3-5% cows or there is a cluster of abortions
When should you investigate sow abortion?
only in outbreaks (otherwise Dx unlikely)
What are the 3 most common causes of ovine abortion (2013)?
Chlamydophila - 30%
Toxoplasma - 23%
Campylobacter foetus foetus - 22%
What are the main causes of bovine abortion?
Others (Dystocia, I2 deficiency, Q fever) Neospora - 16% Bacillus licheniformis - 13% Salmonella dublin - 13% Trueperella pyogenes - 9%
Infectious causes of abortion in sows?
PRRS
Parvovirus
Streptococcus spp
Other
What are causes of equine abortion?
Umbilical cord anomaly - 37% (twists)
Miscellaneous (dystocia, neonatal death) - 28%
EHV - 19%
Bacterial/fungal placentitis - 16%
QUESTION IN CASES OF MARE ABORTION: is the cause EHV or something else?
What are signs of foetal distress?
meconium staining, meconium in trachea/lung or oesophagus/stomach
What does an autolysed foetus indicate?
it died too quickly to initiate its own parturition (most cases)
How should you investigate aboriton?
Detailed history
Submit - placenta, ‘fresh’ foetus AND maternal serum. hopefully entire
Interpret results in relation to premises
Seek advice if unsure
List some non-infectious causes of abortion
dystocia twinning - mare, cow umbilical cord anomalies placental insufficiencies - mare congenital/genetic aplasia/hypoplasia of adrenal, anomalies in anterior pit. husbandry seasonal infertility - sows toxins nutritional - TE deficiencies stress induced - corticosteroids spontaneous (no apparent cause)
What is an amporphous globosus?
= an acardiac monster
a shapeless mass
incomoplete twin with vascular connection to placenta of its twin
all three primary germ layers present
List some zoonotic causes of abortion - 7
Brucella Salmonella Campylobacter foetus Leptospira Listeria Chlamydophila Coxiella burnetti
How are bacterial and fungal diseases diagnosed? 5
Culture - foetal stomach contents (lung/liver). Not possible for some bacteria (Leptospira - PCR of kidney; Chlamydophila abortus - impression smears of placenta stained with mZN, PCR, IHC)
Selective bacterial culture (Campylobacter spp, Listeria monocytogenes, Brucella spp, fungi)
Macroscopical and histopathological examination - foetal tissues and placenta
Serology - maternal, foetal
Fungal wet preparations - foetal stomach contents (placenta)
What is the main mycotic cause of abortion?
Aspergillus fimigatus
Outline mycotic aboriton
CATTLE: mainly haematogenous
MARES: mainly ascending
WHEN: mostly sporadic, outbreaks associated with poor quality feed,
APPEARANCE: thickened leathery placenta covered with exudate, elevated greyish plaques on foetal skin and eyelid
DIAGNOSIS: fungal culture/fungal wet preparation of foetal stomach contents
What are notifiable viruses causing foetal loss? 4
Aujesky’s = pseudorabies
CSF (also ASF)
BTV
EVA
How are viral abortions diagnosed?
PCR (PRRS, EHV-1, BVDV, SBV, EVA, FeLV)
(Virus Isolation 0 rare)
Histopathology (herpes inclusion bodies) +/- IHC or IF
Serology: maternal, foetal (free foetal fluids)
What are the 3 main protozoal causes of foetal loss?
Neospora caninum
Tritrichomonas foetus
Toxoplasma gondii
What does this describe?
PI - cattle
Repeat abortions - rare but occur
Dog - responsible for horizontal transmission
Vertical transmission most common
Every calf of an infected dam will be positive for this
Dx = PCR of brain stem
Histopath. of heart (myocarditis), brain (encephalitis), IHC to confirm
Neospora caninum
What does the following describe?
cattle Transmitted at coitus (lives in male prepuce) foetal maceration common endometritis/pyometra time of abortion (2-4 months)
Tritrichomonas foetus
Can T. gondii affect goats?
Yes - mainly sheep
What can cause hydrancephaly? 2
BTV and SBV
What can cause cerebellar hypoplasia? 1
BVD
