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Y3 SPRING > AG MED - GI - Bovine Viral Diarrhea Virus & Mucosal Disease > Flashcards

AG MED - GI - Bovine Viral Diarrhea Virus & Mucosal Disease Flashcards

1
Q

What are the biotypes of bovine viral diarrhea (BVD)?

Which cause clinical infection and disease?

Which can cause persistently infected animals?

A

Non-cytopathic (NCP)
Cytopathic (CP)

BOTH

Non-cytopathic

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2
Q

Name three pestiviruses

A

BVDV
Border Disease
Hog Cholera

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3
Q

Which BVD biotype is more predominant and persists in cattle populations?

A

Non-cytopathic

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4
Q

How does cytopathic BVD come about?

A

Via mutation of non-cytopathic biotype

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5
Q

What causes mucosal disease (MD)?

A

Co-infection of homologous noncytopathic and cytopathic BVD

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6
Q

What are the two genotypes of BVD?

How many subspecies does each have?

What biotypes does each have?

Are they antigenetically and genetically dissimilar?

Do they cause similar disease syndromes?

A

Type I
* 21 subspecies
* Noncytopathic and cytopathic

Type II
* 4 subspecies
* Noncytopathic and cytopathic
* Thrombocytopenia

YES
YES

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7
Q

What percentage of the general cattle population is persistently infected with BVD?

What percentage of herds have at least one persistently infected animal?

A

2% of general cattle population

10 - 50% of herds have at least one persistently infected animal

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8
Q

How long does the bovine viral diarrhea virus last in the environment?

How is bovine diarrhea virus transmitted?

A

Less than two weeks

Virus is in most body secretions
- direct contact (ingestion, inhalation)
- transplacental (virtually 100%)
- vectors (insects, inanimate)
- semen

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9
Q

What is the range of clinical signs with BVD?

A

Subclinical ——> death

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10
Q

What factors do the clinical signs of bovine viral diarrhea depend upon? (6)

A

Immunotolerant vs immunonaive
Immune status
Pregnancy
Gestational age
Environmental stress
Genetic diversity of virus

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11
Q

When does persistent infection for BVD occur?

Which biotype are persistently infected cows infected with?

A

30 - 150 (or less than 125) days gestation

Noncytopathic

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12
Q

What happens when a pregnant cow becomes infected with bovine viral diarrhea virus?

A
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13
Q

What are two outcomes for persistently infected calves?

A
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14
Q

When do 85% of acute cases of BVD occur?

What is the morbidity/mortality for acute BVD?

How long does the acute infection last?

A

In the first year of life

High morbidity, low mortality

Infected for several weeks; short-lived viremia (2-3 weeks)

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15
Q

Acute BVD damages the epithelium of what three systems?

A

GIT
Integumentary
Respiratory

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16
Q

Are acute cases of BVD persistently infected or transiently infected?

What clinical signs would you expect to see?

What clinical signs would you expect to see in adult dairy cattle?

A

Transiently infected

Varying levels of:
- fever, lethargy
- nasal/ocular discharge
- diarrhea/enteritis
- mucosal erosions
- neutropenia
- respiratory disease

Profuse diarrhea and agalactia

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17
Q

What does a typical manifestation of acute BVD look like?

A
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18
Q

What is thrombocytopenia/hemorrhage syndrome?

What is its mechanism?

What are the clinical signs?

A

Acute type II noncytopathic bovine viral diarrhea virus
Higher mortality and more severe signs

Virus associated with platelets, megakaryocytes and platelet function is altered

CS: severe GIT bleeding, epistaxis, hyphema, bleeding from injection sites, etc.

19
Q

What does this photo show?

A
20
Q

What condition can be clinically indistinguishable from severe acute bovine viral diarrhea?

A

Mucosal disease

21
Q

Clinical signs of mucosal disease

A

Fever
Lethargy
Dehydration
Diarrhea
Mucosal erosions
Neutropenia
Lymphopenia
Respiratory disease
Acute death

22
Q

How does a persistent infection of mucosal disease occur?

???

A

Following fetal infection at less than 125 days with the noncytopathic BVD virus

???

23
Q

Chronic Mucosal Disease

How long can they survive?

Clinical signs?

A
24
Q

What is the most common origin of mucosal disease infection?

What is a rare but possible origin?

A

Combined infection of antigenically homologous noncytopathic and cytopathic virus caused by:

Spontaneous mutation of NCP —-> CP (common)

Natural or iatrogenic (MLV vaccine) infection (rare)

25
Q

How does BVD lead to immunosuppression?

A
26
Q

CNS and congenital defects such as those below can be seen with fetuses infected when?

Cerebellar hypoplasia
Hydranencephaly / hydrocephalus
Eye problems: micropthalmia, retinal atrophy, cataracts, optic neuritis
Pulmonary hypoplasia
Skeletal defects
Thymic hypoplasia

A

100 - 170 days

27
Q

What condition is shown here?

A

Cerebellar hypoplasia

28
Q

Outcomes of in utero and congenital infections of BVD during each trimester:

1st (0 - 110 days)

2nd (111 - 180 days)

3rd

A
29
Q

Reproductively, what other syndromes might be seen with BVD/MD?

A
30
Q

BVD/MD Leukogram:

A
31
Q

BVDV / MD - Differentials for diarrhea without oral erosions (8)

A

Some winters John cuts out couscous, grain, & rice

32
Q

BVD / MD - Differentials with oral/vesicular lesions (6)

Vehicles may enter for pod racing

A

Vesicular stomatitis
Malignant Catarrhal Fever
BT/EHDV - Epizootic Hemorrhagic Disease Virus
Foot and Mouth Disease
Papular Stomatitis
Rinderpest

33
Q

What herd record details might raise your suspicion for BVD? (3)

A

Decreased production
Poor repro performance
Signs of immunosuppression (high incidence of disease)

34
Q

What condition is shown here?

A
35
Q

What condition is shown here?

A
36
Q

Definitive diagnosis of BVD/MD

A
37
Q

Treatment for BVD/MD

A

None for mucosal disease
Supportive care for acute BVD
Hemorrhagic syndrome may need transfusion

38
Q

Control and management of BVD/MD

Most important goal?
Which animals to test and how?
Any quarantine?
Is vaccination effective?

A
39
Q

BVD/MD Control and Management - WADDL recommendations

A
40
Q

What test is used to determine type I and II BVD if not vaccinated?

Which test is so sensitive it cannot differentiate PI vs TI?

Which test is a good screening test and may be better for detecting PIs than ELISA?

Which test is used for export testing, takes 5-9 days for results, and is not used for screening?

A

Serology - antibody

PCR - DNA

IHC - Ag (ear notch)

VI - Ag (EDTA, tissues)

41
Q

What is the goal of vaccinating cows from BVD?

When should cows be vaccinated?

A

To prevent fetal infection

2 weeks - 2 months before breeding
Revaccinated annually

42
Q

What is the goal of vaccinating calves against BVD?

When should calves be vaccinated?

A

Protect against systemic infection

3-4 weeks before weaning
3 times during the first year
+/- branding

43
Q

What does BVD control gain you?

A

Y3 SPRING (40 decks)

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