7: Bovine Abortions Flashcards

1
Q

What are diseases that cause late term abortions?

A

BHV-1, Mycoses, Brucellosis, Lepto, Opportunistics, Neospora, Epizootic Bovine Abortion

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2
Q

What are diseases that can cause abortions at any time?

A

Ureaplasma, mycoplasma
BVD, bluetongue, Listeria

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3
Q

Three mechanisms of hematogenous abortion:

A

Infect fetus directly through umbilical veins
Infect fetus indirectly through contamination of amnionic fluid from primary placental infection
Hypoxia via placentitis (no fetal infection)

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4
Q

Two main routes of abortifacient infection:

A

Hematogenous dam-> placenta
Ascending infections from vagina through cervix

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5
Q

When do losses due to campylobacter occur?

A

Majority 30-70d
Occasionally at 4-8 mo

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6
Q

Campylobacter mechanism:

A

Heat-stable endotoxin-> placentitis-> fetal hypoxia

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7
Q

Mollicute infection abortion presentation:

A

EED/Abortion/Stillbirth/Weak calves/Neonatal pneumonia
Retained fetal membranes common
White-brown exudate and thickened, fibrotic, necrotic, amnion & chorioallantois

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8
Q

Mollicute infection tx:

A

Macrolide abx

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9
Q

Mollicute transmission:

A

Venereal or respiratory
Likes mucosal/serosal surfaces

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10
Q

When do opportunistic infections cause abortion:

A

2nd half of gestation
variable presentation
Dx of exclusion

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11
Q

Where is epizootic bovine abortion more common?

A

California, Oregon, Nevada
“Foothill Abortion”

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12
Q

What is the mechanism of Epizootic bovine abortion?

A

Tick borne
Replication in histiocytes-> fetal stress-> parturition induction
SLOW infection

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13
Q

When are cattle susceptible to EBA and when does it cause abortions?

A

Susceptible mid-gestation (60-140d)
Abortions in 3rd trimester

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14
Q

Mechanism of brucellosis abortions:

A

Penetrates resp. mucosa-> localizes in lymph nodes-> bacteremia-> uterus-> trophoblast necrosis and chorioallantoic ulcertation (placentitis)-> fetal bacteremia

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15
Q

Gross pathology associated with brucellosis abortions:

A

Moroccan leather placenta (dry, thickened, cracked) may be covered in yellowish exudate

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16
Q

What does brucellosis cause in cows?

A

Spontaneous late term abortions, premature calving, infertility

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17
Q

Compare Lepto serovars hardjo and pomona on terms of timing and abortion rates:

A

Pomona: higher abortion rate (50%); 3rd trimester abortions; 1-6 wk post infection
Hardjo: <10% abortion rates; 2-3rd trimester abortions; 4-12 wk post infection

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18
Q

Mechanism of leptospirosis abortions:

A

Infection-> 4-10d incubation-> bacteremia-> localizes/persists in repro & kidneys-> persistent shedding in urine & repro fluids-> May deliver weak infected calves or autolyzed/icteric fetus

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19
Q

Presentation of Lepto abortions:

A

Weak infected calves
Autolyzed & icteric
Diffuse cotyledonary necrosis
RFM common

20
Q

Mechanism of listeria abortions:

A

Spoiled silage consumption-> hematogenous spread to placenta (5-12 days)-> fetal septicemia

21
Q

Timing of listeria abortions:

A

Early third trimester- retained for a few days
Or near full term; less autolysis

22
Q

Presentation(s) of listeria abortions:

A

Early 3rd trimester- severe autolysis
Near term- dam metritis, septicemia, dystocia, RFM; less autolysis, multifocal cotyledonary necrosis, intercotyledonary placentitis, fibrinous polyserositis & white necrosis of liver/spleen

23
Q

Mechanism of BVDV abortion:

A

Oronasal inoculation-> replicates in tonsils & resp tract-> disseminated to other epithelial/lymphoid tissues-> transplacental infection

24
Q

Infection of BVDV at <40d:

A

Decreased conception rate/EED
Oophoritis, salpingitis, hormone alteration

25
Q

Infection of BVDV at 40-125 days:

A

Pregnancy loss or PI animal (non-cytopathic)

26
Q

Infection of BVDV at 100-150 days:

A

Congenital malformations
Cerebellar hypoplasia, hydranencephaly, hydrocephalus, porencephaly, microcephaly, ocular changes

27
Q

Infection of BVDV >125 days:

A

Abortions rare
Clinically normal calf with high antibodies

28
Q

Bluetongue vector:

A

Biting midge
Cullicoides variipennis

29
Q

Bluetongue mechanism:

A

inoculation-> LN replication-> hematogenous spread-> cell damage/thrombosis

30
Q

Bluetongue infection at <70d:

A

fetal death/absorption

31
Q

Bluetongue infection at 70-130d:

A

Stillbirth, weak calves, hydrancephaly, abortion

32
Q

Bluetongue infection at >150 days:

A

premature birth +/- encephalitis

33
Q

Sources of IBR:

A

Nasal exudates, cough droplets, preputial secretions, semen, fetal tissues/fluids

34
Q

IBR abortion mechanism:

A

Infection of non-immune pregnant females-> viremia-> rapid fetal infection-> abortion

35
Q

Timing of IBR abortions:

A

most common between 4 and 8 months

36
Q

Presentation of IBR abortions:

A

Variable autolysis
White-tan foci on liver/lungs
Edematous placenta

37
Q

Horizontal transmission of neospora:

A

cattle ingest oocysts

38
Q

Exogenous transplacental transmission of neospora:

A

naive animal ingests oocysts while pregnant; passes to fetus

39
Q

Endogenous transplacental transmission of neospora

A

latent infection reactivates during pregnancy and is passed to the fetus

40
Q

When do neospora abortions occur?

A

2nd trimester 5-6 mo

41
Q

Mechanism of neospora abortions:

A

disorder of fetoplacental unit following maternal parasitemia
Parasite invades & damages placental villi

42
Q

Most common cause of mycotic abortions:

A

Aspergillus fumigatus

43
Q

timing of abortions from mycoses:

A

sporadic, late term

44
Q

Mechanism of mycotic abortions:

A

Resp/GI introductions-> bloodstream-> placental necrotizing vasculitis with thrombosis-> placental insufficiency-> abortion
Placenta frequently retained

45
Q

What infectious abortifacients do we not have a vaccine in the US for?

A

Bluetongue
Neospora
Mycotics
Listeriosis

46
Q

What is in a commercial 5-way vaccine

A

BVD (x2), BHV-1, BRSV, PI3

47
Q

What is in a commercial 10-way vaccine?

A

BVD, BHV-1, BRSV, PI3, Campy, Lepto