Lecture 13 (Viral Diseases of Cattle II)

Question 1

Bovine Viral diarrhea (BVD/Mucosal Disease)

Answer 1

-recognized in North America in 1945
-spreads by contact and most secretions/excretions contain virus
-inapparent, acute sporadic with death (mucosal disease), chronic
-abortion and congenital deformities
-no corneal opacities
-gut lesions involve depletion of Peyer’s patch & ulcerations

Question 2

what are the clinical signs of an acute infection of BVD?

Answer 2

-usually subclinical
-diarrhea
-depression
-oculonasal discharge
-anorexia
-decreased milk production
-oral ulceration
-pyrexia
-leukopenia

Question 3

what are the properties/characteristics of Flaviviruses?

Answer 3

-virus is unstable in the environment
-wide range of systemic clinical presentations most importantly encephalitis
-many serotypes with type specific immunity
-diagnosis by clinical presentation confirmed by ELISA, PCR, or virus isolation
-biological transmission by arthropods (flaviviruses)

Question 3

t/f: if a persistently infected (PI) calve with BVD grows up to become a breeding animal, they will always give birth to a PI calf

Answer 3

true

Question 3

____-____% of non-vaccinated or immunocompromised cattle become infected when exposed to a persistently infected cow with BVD

Answer 3

70-100%

Question 3

what was the first animal disease to be recognized as caused by a virus, and is the most important disease of ruminants when considering world-wide?

Answer 3

Foot and Mouth Disease

Question 4

-cerebellar hypoplasia
-persistently infected calves may develop mucosal disease and die
-spastic or dummy calf
-infections that occur later in gestation result in abortion, stillbirths, or the birth of normal, seropositive healthy calves

Answer 4

congenital BVD

Question 5

what is the incubation period for Foot-and-Mouth disease?

Answer 5

2-14 days

Question 6

is Foot and Mouth Disease found in the U.S.

Answer 6

no - it is a foreign animal disease and was an epidemic in 2001 in the UK

Question 7

this is a disease of cattle caused by Flaviviruses or specifically the Genus Pestivirus:

a) BRD
b) BVD
c) Border Disease
d) Hog Cholera

Answer 7

b) BVD

Question 8

the acute form of Bovine Viral Diarreha can seem clinically siimilar to Infectious Bovine Rhinotracheitis and Malignant Catarrhal Fever with erosion of the alimentary tract. One key difference in signs that separates acute BVD from IBR/MCF is…

a) BVD is associated with corneal opacities and IBR/MCF are not
b) BVD is not associated with corneal opacities but IBR/MCF are

Answer 8

b) BVD is not associated with corneal opacities but IBR/MCF are

Question 9

this disease, caused by a Flavivirus, is associated with “Mucosal Disease”

a) Bovine Viral Diarrhea
b) Bovine Syncytial Virus
c) Bovine Vesicular Stomatitis
d) Bovine Papular Stomatitis

Answer 9

a) Bovine Viral Diarrhea

Question 9

this disease affects all age groups and is associated with a wide range of signs: acute diarrhea with sporadic death, mucosal disease, chronic disease, abortion, congenital deformities

a) Bovine Viral Diarrhea
b) Bovine Syncytial Virus
c) Bovine Vesicular Stomatitis
d) Bovine Papular Stomatitis

Answer 9

a) Bovine Viral Diarrhea

Question 10

“Mucosal Disease” includes gut lesions that involve depletion of Peyer’s patches and ulcerations and is an occasional presentation of:

a) BVD
b) IBR
c) RSV
d) BVS

Answer 10

a) BVD

Question 11

in this disease, transmission across the placenta can lead to a Persistently Infected calf (PI Calf) that then spreads the disease and is quite costly

a) IBR - a herepesvirus
b) BVD - a flavivirus
c) RSV - a paramyxovirus

Answer 11

b) BVD - a flavivirus

Question 12

which of the following is not true regarding the life cycle of BVD:
a) calves become infected while in the uterus
b) 50% of of PI calves will be “poor doers” and die within 1 year
c) a portion of PI calves will have inapparent infection, but a suppressed immune system
d) surviving PI calves shed the virus daily exposing other cattle
e) all of the above are true

Answer 12

e) all of the above are true

Question 13

-cerebellar hypoplasia
-spastic/dummy calfs
-low weight gain
-potential development of lethal Mucosal disease are signs of:

a) Congenital RSV
b) Congenital IBR
c) Congenital Herpesvirus infections
d) Congenital BVD

Answer 13

d) Congenital BVD

Question 13

which of the following is true regarding BVD virus infections in a pregnant cow:

a) they can cause abortion
b) they result in still births
c) they result in the birth of seropositive healthy calves
d) all of the above

Answer 13

d) all of the above

Question 14

which of the following is most important regarding the vaccination against BVD?

a) there are two types of BVD virus and there is no antigenic overlap
b) vaccines need to be used before pregnancy to be effective
c) BVD is often addressed in a combo vaccine with IBR, RSV, and PI3

Answer 14

b) vaccines need to be used before pregnancy to be effective

Question 15

-zoonotic disease causing variant Creutzfeldt-Jakob disease (vCJD) in young people
-vCJD is a type of brain disease within the transmissible spongiform encephalopathy family
-symptoms: psychiatric problems, behavioral changes, painful sensations

Answer 15

Bovine Spongiform Encephalopathy (BSE)

“Mad Cow Disease”

Question 15

-very infectious
-incubation 2-14 days
-caused by a virus (picornavirus)
-transmitted between countries in meat products
-possibly could occur in the USA
-humans are rarely infected
-BCS & milk production decreases

Answer 15

Foot-and-Mouth Disease

Question 16

-in its severest form it can kill ~95% of a herd
-virus is related to those of measles and canine distemper
-remained endemic in Africa until 2001
-the concept of vaccination was introduced as the basis of this viral control
-eradication achieved through mass vaccination of cattle

Answer 16

Rinderpest

Question 17

-brain degeneration with vacuolation
-long incubation period (2.5 years and >)
-infectivity is very hard to inactivate (cooking is ineffective)
-no host immune response is detectable
-invariably fatal
-transmitted by a common vehicle (meat products)

Answer 17

Transmissible Spongiform Encephalopathies (TSE’s)

Question 18

all TSEs, in the late stages of the disease, show an accumulation of infectious ________ proteins and vacuoles in the CNS

Answer 18

prion

*proteinacious infectious particles (PrP)

Question 19

normal PrP is routinely synthesized and metabolized by proteinase _____ enzymes

Answer 19

K

Question 20

-slaughter of affected animals and incineration
-non recycling of animal proteins to ruminants

a) BSE
b) vCJD

Answer 20

a) BSE

Question 21

-in UK, age restriction on cattle going to slaughter for human consumption
-removal of brain and CNS tissue from human food chain

a) BSE
b) vCJD

Answer 21

b) vCJD