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E - F repro > Farm animal abortion > Flashcards

Farm animal abortion Flashcards

1
Q

what is the difference between abortion and still birth?
What is a bovine abortion?

A

Abortion = birth before full term, of a dead or non-viable foetus
Stillbirth = birth at full term, of a dead or non-viable foetus
Bovine abortion = Expulsion of a foetus between the completion of differentiation (day 42) and the limit of foetal independent viability (day 265).

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2
Q

why do we investigate abortion?

A
  • Economic impacts – calf, milk, AI, feed etc.
  • Wider significance or an easily solved problem?
    • Public Health – zoonoses e.g. Salmonellosis
    • Neospora – nearby footpaths
    • Poor nutrition
  • Statutory Requirement – Brucellosis Order
  • The legislation requires anyone in charge of bovine animals to report any abortion or premature calving (< 271 days after service or < 265 after implantation whether calf is dead or alive) within 24 hours.
  • Suspicion of Brucella abortus must be reported to APHA in the same way as other notifiable diseases.
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3
Q

what are the general themes of approaching an abortion case?

A
  • history - individual and herd, clinicla signs in dam
  • foetus quality
  • decide adn intervention figure
  • sampling - serology, PM of foetus
  • list differentials
  • biosecurity and zoonosis
  • control/treatment plan
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4
Q

why are diagnositc rates for abortion low?

A
  • Non-infectious causes
  • Cost
  • Limited farm history & data
  • Sample quality & quantity
    • No placenta
    • Bacterial contaminant overgrowth
    • Autolysis
    • Cattle – time to abort
  • Laboratory test limitations – only so many things can be tested for!
  • Sampling bias – some farmers sample every abortion, some only with a disaster!
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5
Q

what are the non-infectious causes of abortion in cattle?

A

common in cattle, but difficult to prove:
* Hereditary disorders/congenital defects
* Toxins e.g. ergot, nitrates, brassicae, mycotoxins, hemlock, heavy metals
* Trauma/physical factors
* Prostaglandins – endogenous (stress), inflammation, pyrexia; exogenous
* Nutritional deficiencies/toxicities – severe starvation, pregnancy toxaemia, vit. A, iodine, selenium, manganese
* Concurrent disease – liver fluke, pneumonia, Johne’s, lungworm etc.

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6
Q

what are the viral causes of abortion in cattle? which are notifiable?

A

BVD
IBR – BoHV-1
Schmallenberg virus
Bluetongue virus - notifiable

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7
Q

what are the bacterial/Rickettsia causes of abortion in cattle? Which are notifiable and zoonotic?

A

Brucellosis - notifiable and zoonotic
Leptospirosis - zoonotic
Salmonellosis - zoonotic
Bacillus licheniformis
Listeria spp. - zoonotic
Coxiella burnetti (Q Fever) - zoonotic

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8
Q

what are the fungal, protozoa and sporadic infectious cuases of abortion in cattle? which are notifiable and zoonotic?

A

Fungal – Aspergillus, Absidia, Rhizopus etc.
Protozoal
* Neospora caninum
* Trichomoniasis

*Sporadic causes *
* Trueperella pyogenes
* E. coli - zoonotic
* Histophilus somni
* TB - notifiable

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9
Q

what are the viral causes of abortion in sheep? which are notifiable?

A

Border disease
Bluetongue virus - notifiable
Schmallenberg virus

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10
Q

what are the bacterial/rickettsia causes of abortion in sheep? which are notifiable and zoonotic?

A

Campylobacter fetus fetus, Campylobacter jejuni - zoonotic
Listeria spp. - zoonotic
Salmonellosis - zoonotic
Leptospirosis - zoonotic
Brucellosis - notifiable
Coxiella burnetti (Q Fever) – Rickettsia - zoonotic
Tick Borne Fever - Anaplasma phagocytophilum

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11
Q

what are the protozoal causes of abortion in sheep? is this zoonotic or notifiable ?

A

toxoplasma gondii - zoonotic

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12
Q

How is neospora canium transmited to cattle and within cattle?

A

protozoal parasite:
* Canines are the definitive host but vertical transmission much more common
* Exogenous transmission = Canine ingestion of tissue cysts e.g. in placenta –>oocysts passed in faeces –> contaminate feed/water –> cow injests infectious dog faeces –> cysts primarily in neural tissue –> Vertical transmission withing cow from tachyzoites, via the placenta –> foetus
* Endogenous transmission = Previously/persistently infected cow has reactivation of tissue cysts

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13
Q

what are the clinical signs of neospora caninum in cattle?
what problems does this cause in a herd?

A
  • Abortion typically at 4-7 months but can cause resorptions, mummification, stillbirth, or may be born alive and persistently infected +/- congenital CNS disease
  • Persistently infected calves grow to become persistently infected cows –> 40-50% abort in their first year, or results in vertical transmission
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14
Q

how is neospora caninum diagnosed and prevented?

A

Diagnosis
* Serology in cows
* Negative – rules out Neospora
* Positive – not diagnostic as not definitely the cause
* Antibody levels tend to be highest 10 to 4 weeks before calving
* PCR on foetal brain
* Histopathology +/- IHC on fixed brain

Prevention
* Infected dog faeces
* Remove access to placental material
* Test purchased cattle
* Avoid retaining breeding heifers born from seropositive cows
* Test and cull cows

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15
Q

what occurs if a cow is infected with BVD in pregnancy?

A

Abortion can occur at any point in gestation (usually 1st/2nd trimester)
* 0 - 30 days – infertility or early embryonic death
* 18-125 days – PI calves
* 80-150 days – congenital defects e.g. cerebellar hypoplasia, cataracts, hydrocephalus etc.
* > 150 days – the calf can launch an immune response and often survives

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16
Q

how is BVD diagnosed? what is the control?

A

PCR, antigen and antibody testing available
* PI calf – antigen positive, antibody negative
* PCR on aborted calf tissue (spleen often used)
* Antigen or antibody testing on blood (avoid antibody testing on post-colostral neonatal calves)
* Antigen/PCR testing on tissue in live animals e.g. ear tag
Control – routine herd testing, culling PIs, vaccination

17
Q

what are the risk factors for leptospirosis in cattle?
what are the clinical signs?
how is it diagnosed?
how is it controlled?

A
  • Higher risk if grazing with sheep
  • Clinical signs – infertility, abortion usually >6 months, premature calves, milk drop
  • Diagnosis
  • PCR on foetal kidney, lung, or placenta
  • Histopathology – foetal interstitial nephritis is pathognomonic
  • Control and treatment
    • Vaccination
    • Avoid grazing with sheep
18
Q

what is the main species of almonella in cattle?
what does salmonella cause in cattle?
how does it get on farm?
how is it diagnosed?
what is the the prevention?

A
  • Primarily S. Dublin- ~80%
  • Sporadic cause of abortion +/- dysentery and pyrexia in cows
  • Introduction of carrier animals or contamination of feed/water
  • Diagnosis – culture from foetal stomach contents
    • Serology may be useful, but titres fall rapidly after abortions
    • Faecal culture from the dam has low sensitivity
    • Cows that abort shed for a very short period of time compared to enteric cases where there is intermittent or continuous shedding
  • Prevention – vaccination, destroy contaminated bedding, isolate cows until vaginal discharge stops
19
Q

what are the clinical signs of these species of salmonella in sheep?
S. abortusovis
S. montevideo
S. typhimurium
S. Dublin

A
  • S. abortusovis – few clinical signs other than abortion in the last 6 weeks of gestation
    • Lambs may be born alive but die within the first week of life
  • S. montevideo – few clinical signs other than abortion, no diarrhoea in lambs
  • S. typhimurium – pyrexia, anorexia, and profuse scour in ewes with foul smelling vaginal discharge
    • May be fatal
    • Lambs not aborted may be born stillbirth, or born alive and die soon after with evidence of scour
    • Outbreaks often follow times of stress
  • S. Dublin – clinical signs similar to S. typhimurium but usually not as severe
20
Q

what is the diagnosis, treatment and prevention of salmonella in sheep?

A

Diagnosis – culture of foetal stomach contents
Treatment – treat ewes with a sensitive antibiotic if necessary
Prevention – vaccination, isolate aborted ewes, avoid stress etc.

21
Q

what are the clinical signs of Campylobacter fetus subsp. venerealis in cattle?
how is it transmitted?
how is it diagnosed?

A
  • Cause of infertility and embryonic death primarily, associated with a mucopurulent endometritis
  • Occasionally abortion at 4-8 months
  • Venereal transmission
    • Cows – fertility returns after 4-8 months once the uterus recovers
    • Bulls – may recover or be infected for life. The older the bull, the more likely to be persistently infected
  • Diagnosis
    • Culture from vaginal washes or preputial scrapings/washes – difficult to culture successfully
    • Vaginal Mucous Agglutination Test – picks up ~50% of positive cows
    • Serology – very poor humoral response to venereal infection so of little value
22
Q

how is Campylobacter fetus subsp. fetus
transmitted in cattle?
what are the clinical signs?
how is it diagnosed?

A
  • Found in the intestinal tract  faeco-oral transmission
  • Placental lesions – necrosis, intercotyledonary thickening and oedema, yellow-brown cotyledons
  • Placental culture is difficult due to other contaminants overgrowing
  • Foetal stomach contents – Campylobacter enrichment cultures
23
Q

how is Campylobacter fetus fetus and C. jejuni transmited to sheep?
what are the clinical signs?

A

Campylobacter fetus fetus – from carrier sheep;
C. jejuni from wildlife vectors
Faeco-oral transmission –> ewe to ewe transmission

Clinical signs – infection –> abortion 7-25 days later, followed by strong immunity
* Abortion in the last 6 weeks of gestation and weak lambs born alive.
* May see diarrhoea as well as abortions.
* Up to 25% of ewes may abort in naïve flocks.
* Very few clinical signs in ewes other than abortion initially, though metritis may develop
* Aborted material is infectious
* Venereal spread not a feature (as in cattle – Campylobacter fetus venerealis)

24
Q

how is campylobacter diagnosed in sheep?
how is it prevented?

A

Placenta may have intercotyledonary oedema and cotyledonary necrosis
Foetal livers may have multifocal areas of grey necrotic foci – pathognomonic
Culture – foetal stomach contents (or placenta, or liver)

prevention:
Some people will mix aborted ewes with lambed ewes to generate immunity

25
Q

how is toxoplasma gondii transmited to sheep?
what does it cause in sheep?

A

infection is through ingestion of oocysts shed in cat faeces. - Cats are definitive host – sheep (and other mammals) are intermediate hosts.
Oocysts may survive for up to 2 years on pasture, feed, or bedding.

Causes infertility, mummification, stillbirth and abortion depending on stage of gestation and infective dose.
< 60 days –> foetal resorption –> high barren rate if ram has been removed
Mid-gestation –> abortion or mummification
> 120 days –> stillbirth, weak lambs, or normal lambs

26
Q

how is toxoplasma gondii diagnosed and controlled?

A

Diagnosis – ‘frosted strawberry’ cotyledons
* Intercotyledonary areas unaffected (c.f. C. abortus)
* PCR – placenta
* Foetal serology – foetal fluid
* Maternal serology – antibodies can remain elevated for years (paired?)
Control – retain aborted ewes, keep old neutered cats on farm, and vaccinate!

27
Q

what does chlamydia abortus (EAE) cause in sheep?
how is it diagnosed and controlled?

A

> 80% of outbreaks are from the purchase of infected ewes
* Ewes infected early in pregnancy may abort this year. If non-pregnant or in late gestation (~>100d), they lie dormant until the next pregnancy (will then abort).
* Results in late-term placentitis and abortion typically in the last 3 weeks of gestation.
* Some ewes become carriers and may excrete organism in their faeces.

Diagnosis
* Ewes are not ill
* Intercotyledonary areas are thickened, leathery, and oedematous
* Necrosis of foetal cotyledons
* May get birth of weak lambs
* Smears from intercotyledonary areas are stained with a modified ZN stain –> intracellular cocci seen
* Serology – maternal or foetal fluids

Control – retain ewes, biosecurity, vaccinate, antibiosis (prophylactic use of Oxytetracycline, to maintain the placenta until the end of pregnancy)

28
Q

what infectious causes of abortion in sheep can be vaccinated against?

A

Chlamydia abortus (EAE), Toxoplasmosis, Campylobacter (import), Salmonella abortusovis

29
Q

what virus is spread to foetuses by culicoides midges?
what are the clinical signs?
if you see these clinical signs what do you need to do and why|?

A

Schmallenberg virus

May see pyrexia, diarrhoea, anorexia, milk drop
Abortion and stillbirth, with congenital defects
* Arthrogryposis most common defect
* Neurological defects – hydrancephaly, hydrocephalus, cerebellar hypoplasia, porencephaly

if you see fluid filled cavities in foetuses then could be BVD or bluetounge virus and therefore need to report to APHA

E - F repro (13 decks)

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