Pathology Pregnant Genital Tract Flashcards
Define embreyo
- time fertilised embreyo begins to develop a long axis to the time that major structures begin to develop (incomplete orgnaogenesis)
- horse/cattle ~ <35-45d
Define foetus
developing viviparous organism after embreyonic stage and before birth
Define abortion
Premature EXPULSION of the produces of conception from the uterus (not just death)
Which species are dependent on the CL for the whole pregnancy?
- cattle, goats, pigs, dogs
Which species are only dependent on the CL for early pregnancy?
- horse, sheep, cat
WHat initiates parturition?
- foetal stress (including foetal/maternal illnes, hyperthermia)
- foetal ACTH -> foetal GCs -> ^ oestrogens from placenta -> ^ myometrial OTRs and ^ PGF2a -> myometrial contraction, luteolysis, v P4 -> relaxin secretion -> placental separation from endometrium -> fresh non-autolysed foetus
What type of pregnancy loss does salmonellosis/septacaemia cause?
- rapid foetal death
- autolysed foetus
Reasons for embreyonic/foetal loss?
- failure of zygote to attach to endometrium > early embryonc losses - chromosomal abnormalities [commonest cause] - inherited disordered - uterine environmental factors > late embreyonic loss - similar causes > foetal losses - placentitis -> ischaemia - other causes eg. septaicaemia
What % embreyonic death can be considered normal in most species?
15-30%
What happens to an embreyo lost early? What does this mean clinically?
Reabsorbed or expelled (may be small so dont see it)
- no diagnositc material available
- infections rare (ureaplsa, tritrichomonas foetus,campylocater) endometritis
WHat are the 3 forms of foetal retention?
- mummification
- maceration
- emphysema
What is SMEDI?
- Stillbirth, mummification, early death adn infertility
- Retention of some dead foetuses with others still being bron alive - especiall seen in pigs with parvo as one foetus is infected after another
What is mummification? Commonly seen with which sp? causes?
- NO bacterial infection
- mostly multiparous animals esp sow
- foetal skin developed enough to withstand autolysis so now odour
- absortion of placental and foetal fluids
- clsoed cervix
- time point of expulsion varies
- genetic, twinning mare,viral (BVD, Parvo sow, CHV) protozoan (toxoplasma) uterine torsion queen, placental insufficiencies
Is dx of a mummified foetus usually possible?
no
Does mummification usually have an effect of subsequent breeding?
NO
What is maceration?
- foetus becomes liquified
- bacterial uterine infection necessary
- reabsorption or expulsioin with purulent exudate
- foetal bones and teeth may remain
- foetid odour
- common with venereal infections (campylobacter foetus venerealis, tritrichomonas foetus, non-specific endometrial infections) -> pyo or endometritis
- uterine perforation possible
What is foetal emphysema?
- putrefactive organsims ascending from vagina (gas producing eg. clostridia)
- petnet cervix
- mostly seen with dystocia/near term incomplete abortion
- putrifactive foetus, dsitends with putrefactive gas, crepitates
- advanced uterine lesions and often fatal to dam due to toxaemia
What is the most common route of infection causing abortion?
- haematogenous
- except mare (bacterial and fungal usually ASCENDING)
Give egs. of veneral infections causing abortion
- tritrichomonas foetus
- camyplobacter foetus venerealis
How many abortions are caused by non-infectious causes in cattle, sheep, pigs and horses?
- cattle: 50%
- sheep: 40%
- pigs: 60-70%
- horses: 60-70%
How may non-infectious causes be detected?
Difficult to detect (mostly chromosomal or environmental abnormalities)
WHat does the pathology report tell you about aboriton causes?
Rules out some diseases but rarely gives definitive diagnosis
Which species have highest diagnostic success of abortions? How does this affect which abortions are recommended for path investigation?
Sheep (cattle and pigs less successful)
- only recommend investigation when abortion >3-5% cows or cluster of abortions
- pigs only investigate outbreaks otherwise dx unlikely
WHat are the top 3 infectious casues of ovine abortion?
- chlamydophila
- campylobacter foetus foetus
- toxoplasma
What are the most comon infectious casues of porcine foetopathy?
PRRS, parvo, strep spp .
What are the most common infectious causes of bovine foetopathy?
- neospora
- bacillus licheniformis (poor quality feed)
- salmonellosis
WHat is the main infectious cause of equine abortions that investigations aim to rule out?
EHV1
can mummified foetuses be tested?
NO
Give non-infectious casues of foetopahty
- dystoia, twinning in mares
- umbilical cord abnormlaities or plaacental sufficiencies
- aplasia/hypoplasi adrenal gland, anterior pituitary anomalies
- husbandry
- seasonal infertility esp sows
- toxins (not common in UK)
- nutiritional (sel/vit E and E)
- stress
- induced (corticosteroids/PGF2a)
- spontaneous - stress?
What is the most common route and pathogen casuing infectious abortion?
Haematogenous bacterial
How does bacteria/fungus cause abortion?
Initiates placentitis
How are bacterial/fungal casues of foetopathy diagnosed?
- culture of foetal stomach contents (ulng/liver)
- selective culturefor campylobacter, listeria, bruccella, fungi
- culture for some bacteria not possible
> leptospira (PCR kidney tissue insted)
> chalmydophila abortus (impression smears of placenta stained with mZN - PCR, IHC)
-maternl and foetal serology - fungal wet preparations of foetal stomach contents
WHat is the most common mycotic cause of abortion?
aspergillus fumigatus
- cattle: haematogenous
- horse: ascending
What may outbreaks of mycotic aboritons be associated with?
Poor quality feeed or sporadic
How do mycotic abortions appear grossly?
- thickened leathery placneta covered with exudate (should be clear and seethrough between cotyledons)
- elevated grey plaques on foetal skin and eyelids
How can mycotic abortions be dx?
- fungal culture/fungal wet preparation of foetal stomach contents
How may viral aboritons be diagnosed?
- PCR (eg. PRRS, EHV1, BVD, SHmallenburg, EV, FeLV)
- virus isolation $$
- histopath +- IHC IF
- serology )maternal/foetal free fluids)
WHat gross changes does EHV1 cause on the aborted foetus?
- multiple focu necrosis on thel iver
WHat gross changes does BVD cause on the aborted foetus?
cerebellar hypoplasia
do protozoal causes usually cause abrtion?
No
what are the 3 main protozoal causes of foetal loss?
> neospora caninum
tritrichomonas foetus
toxoplasma gondii
which species are involved in the lifecycle of neospora caninum?
- dog responsible for horizontal transmission
- persistnet infeciton in cattle (every calf of neospora infected dam will be neospora +)
- vertical transmision most common
how can neospora caninum be diagnosed?
- PCR brain stem
- Histopath of myocardium and brain
How is tritrichomonas foetus transmitted ? WHat does it cause/
- venereal
- lives in prepuce of bulll
- causes foetal maceration and endometritis/pyometra
- aboritons @2-4months
Which species are involed in toxoplasma gondii lifecyce?
- sheep/goats and cats
What does toxoplasma gondii cause?
- timing of infection important
- ZOONOTIC
What diseases should be suspected with hydrancephaly?
- bluetongue
- shmallenburg
