Bovine Abortions Flashcards

1
Q

What cows should you assess first in abortion storm work-ups?

A

Those who have aborted most recently

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2
Q

What should you always submit to the lab when working up abortion cases when available? What should you always collect from moms?

A

Fetus and placenta
Blood

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3
Q

What does campylobacteriosis usually result in?

A

Infertility

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4
Q

What strains of campylobacter are more likely to cause sporadic late term abortions in cattle and small ruminants?

A

Campylobacter fetus ssp fetus and C jejuni

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5
Q

How is campylobacter spread from cow to cow?

A

Feco-oral

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6
Q

When does the majority of pregnancy loss occur with campylobacteriosis infections?

A

30-70 days gestation

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7
Q

What is the pathogenesis of how campylobacteriosis leads to abortion?

A

A heat stable endotoxin is produced with leads to placentitis. Swelling of placenta then leads to fetal hypoxia

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8
Q

How long does it take for infected cows to develop immunity against campylobacteriosis?

A

4-8 months

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9
Q

How do you diagnose campylobacteriosis?

A

rtPCR or IHC

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10
Q

What can mollicute (mycoplasma/ureaplasa) cause in pregnant animals?

A

Embryonic death, abortion, stillbirth, weak calves, neonatal pneumonia- AKA abortion can occur anytime!

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11
Q

How do you diagnose mollicute infections?

A

PCR of vaginal/preputial swabs, abortion-culture/PCR from fetal tissues

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12
Q

What type of antimicrobial is most effective against mollicutes?

A

Macrolides

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13
Q

What type of virus is BVD?

A

RNA, pestivirus, flaviviridae

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14
Q

Where is the site of inoculation of BVD infections?

A

Tonsils and Respiratory tract- then disseminates to other epithelial/lymphoid tissue. Can result in transplacental infections

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15
Q

What occurs when cows are affected at breeding with BVD?

A

Decreased conception rate due to embryonic loss
-etiology: oophoritis, salpingitis, hormone alteration

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16
Q

During what time frame during pregnancy can infection with BVD lead to persistent infection in fetus?

A

40-125 days!

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17
Q

What occurs if cows are affected between 100-150 days in pregnancy with BVD?

A

Congenital malformations-organogenesis, cerebellar hypoplasia, hydrancephaly, hydrocephalus, porencephaly, ocular changes

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18
Q

What occurs if infection with BVD occurs >125 days into pregnancy?

A

Abortions rarely, usually clinically normal calf with high levels of precolostral antibodies

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19
Q

How can you control BVD infections?

A

ID and remove PI animals, enhance immunity through vaccination (MLV before pregnancy ideal), biosecurity to prevent exposure

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20
Q

What type of virus is bluetongue and how is it transmitted?

A

orbivirus transmitted by culicoides varripennis

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21
Q

Describe the pathogenesis of bluetongue virus

A

After inoculation it replicates in the lymph nodes. Through hematogenous spread it then can lead to cell damage and thrombosis
- it can cause prolonged viremia (several weeks) but not persistent infections

21
Q

What occurs if cow infected <70 days gestation with bluetonge? 70-130 days? >150 days?

A

<70: fetal death/absorption
70-130: stillbirth, weak calves, hydrancephaly, abortion
>150 days: premature birth +/- encephalitis

22
Q

Which is detectable to diagnose bluetonge: virus or antibody?

A

Antibody

22
Q

Is there a bluetongue vaccine?

A

Yes, but not labelled for cattle in US

23
Q

What causes infectious bovine rhinotracheitis?

A

Bovine herpesvirus type 1 (double stranded DNA virus)

24
Q

What are the different clinical manifestations of IBR?

A
  1. Mild to severe respiratory disease
  2. Ocular, neonatal, GI or neuro disease
  3. Genital symptoms
  4. Abortions
25
Q

What are the sources of infections for IBR?

A

Nasal exudate, cough droplets, preputial secretions, semen, fetal fluids/tissue

26
Q

Describe the pathogenesis of abortion due to IBR in non-immune cows?

A

Infection in pregnant cows leads to viremia and rapid fetal infection, leading to abortion
-there is variable autolysis

27
Q

When are abortions most common with IBR infections?

A

Between 4-8 months
- dams may or may not have clinical signs

28
Q

What are some post-mortem findings on necropsy of a fetus that died of IBR?

A

Varying degrees of autolysis, white tan foci on liver and lung, edematous placenta

29
Q

When do opportunistic pathogens tend to cause abortion?

A

In the second half of gestation

30
Q

Describe how cows get infected with neospora caninum

A

Dogs ingest tissue cysts in intermediate hosts and release unsporulated oocyts in feces. These can then be consumed by the cow if fecal contamination of food and water occurs. Once tachyzoites are transmitted through placenta, fetus can be infected

31
Q

Compare/contrast endogenous and exogenous transmission of neospora?

A

Exogenous is when the cow gets infected during pregnancy and passes to babe. Endogenous is when cow gets infected in utero and then passes on infection to her calf after infection reactivates during pregnancy

32
Q

When does abortion occur with neospora infections?

A

Early second trimester (5-6 months)

33
Q

Describe how neospora affects the developing fetus?

A

It invades and damages the fetal placental villi

34
Q

T/F: there is a vaccine for neospora

A

F- no vaccine and no treatment!

35
Q

Which leptospirosis serovar leads to the highest abortion rate? during what trimester?

A

Serovar pomona leads to a 50% abortion rate during the third trimester (1-6 weeks after initial infection)

Serovar hardjo leads to a 3-10% abortion rate during the 2nd-3rd trimester (4-12 weeks after acute infection)

36
Q

How is lepto transmitted?

A

Direct contact with infected urine, placental fluids, milk, or transplacental or venereal transmission

37
Q

Describe the pathogenesis of lepto

A

After infection (takes 4-10 d to incubate) bacteremia allows bacteria to localize and persist in kidney and genital tract
-leads to persistent shedding of bacteria in urine and repro fluids

38
Q

What are the findings on the fetus during necropsy in lepto case?

A

Fetuses autolyzed, icteric, diffuse cotyledonary necrosis

39
Q

T/F: Listeria is zoonotic

A

True!

40
Q

When does listeria cause abortions? How?

A

Last trimester- sporadic and rarely exceeds 15%
-causes meningoencephalitits and neonatal septicemia

41
Q

In what weather are listeria infections most common?

A

cold temps

42
Q

What are some fetal post mortem findings in listeria cases?

A

Multifocal cotyledonary necrosis, placentitis, fibrin polyserositis, and white necrotic foci in liver and spleen

43
Q

When does brucellosis lead to abortions?

A

In the last trimester

-also causes premature calving, infertility in cows, orchitis in bulls

44
Q

Describe the pathophysiology of brucellosis?

A

The mucosa of oral or nasal cavities are invaded, then localizes in lymph nodes.
-bacteremia allows spread to uterus leading to trophoblastic necrosis and chorioallantoic ulceration

45
Q

What are some gross findings due to brucella infection?

A

Placenta may be dry, thickened, cracked (moroccan leather looking)
-intercotyledonary placenta may be covered by thick yellowish exudate

46
Q

Why is the brucella vaccine restricted?

A

Human health concerns- can find virus in raw milk

47
Q

When can aspergillus fumigatus lead to abortion in cows?

A

Late pregnancy (6-8 months)

48
Q

Where is epizootic bovine abortion common?

A

California, Oregon, Nevada
-caused by the tick ornithodoros
-most abortions occur in 3rd trimester

49
Q

What are some gross signs of infection with epizootic bovine abortion?

A

Petechial hemorrhage in mucosa of conjunctiva and oral cavity, enlarged lymph nodes, ascites, enlarged liver

50
Q

When are cows most susceptible to infection with foothill abortion?

A

60-140 days (mid-gestation)
-slow infection