Flaviviridae Flashcards
T/F:
The family Flaviviridae consists of positive-sense single-stranded RNA viruses, with most important veterinary viruses falling under the genera Flavivirus and Pestivirus.
True
Which of the following is is true of Bovine Viral Diarrhea Virus 2 biotypes, the noncytopathogenic (ncp) and cytopathogenic (cp)?
A. The ncp is the more common, having the uncleaved form of NS2-3 protein
B. The ncp crosses the placenta and causes persistent infection in calves.
C. The ncp form causes congenital, reproductive and enteric disorders.
D. The cp form arises from mutation of the ncp form in persistently infected calves, forming a nonstructural protein NS2 from cleavage of NS2-3 protein which induces apoptosis of cells and mucosal disease in those calves.
E. All of the above are correct.
E. All of the above
T/F:
Conversion of the ncp biotype of BVDV to the cp biotype is accomplished by insertion of cellular sequences into certain positions of the NS3 gene, leading to an additional protease cleavage site in the viral polyprotein, resulting in cleavage of NS3 and release of NS2-3
False
NS2-3 cleaved to form NS3
Correct, just switch the 2 around
T/F:
In addition to having 2 biotypes (ncp and cp), BVDV has 2 genotypes: BVDV type1 and type 2, both exhibiting both ncp and cp viruses.
True
Ugh who cares??!!
If a cow is infected with Pestivirus in month 5-6 (middle) gestation, what will be the result of her pregnancy?
A. Embryonic death B. Persistently infected calf C. Abortion D. Deformities in calf E. Normal calf
C.
Most likely abortion. As you get into month 7-8, it is more likely to have deformities. Late infection at month 8-9, you will have a normal calf.
If a cow is infected with Pestivirus in month 2-4 of pregnancy, what is the likely result of the pregnancy?
A. Embryonic death B. Persistently infected calf C. Abortion D. Deformities in calf E. Normal calf
B. Persistently infected calf
Which of the following are TRUE about Immunotolerant calves born of mothers infected with BVDV?
A. ncp virus inhibits formation of type I interferon in fetus during gestation, resulting in no antibody response
B. They are also known as Immunotolerant calves
C. PI calves shed virus continuously and are a common source of infection for the rest of the herd
D. These calves may develop mucosal disease, where they have no protection against the cytopathogenic virus
E. All true
E.
T/F:
Hydranencephaly, porencephaly, cerebellar hypoplasia, “star gazing”, and arthrogryposis are common defects seen in calves who are infected with BVDV during month 2-4 of gestation.
False
These are the congenital defects seen when infection occurs in the middle to late stages of pregnancy. Early- embryo death month 2-4= PI calves months 5-6ish=abortion months 6-8isn= defects 8-9= normal calves
T/F:
The acute form of mucosal disease of BVDV is characterized by Peyer’s Patch necrosis or hemorrhage, as well as ulcerations on gums, tongue and dental pad, ulcerations on the coronary bands, abomasal and rumenal ulceration or erosion, as well as a runny nose and dull coat. The Chronic form of mucosal disease is characterized by chronic bloat, emaciation, diarrhea and a rough coat.
True
Which of the following is NOT true of Classical Swine Fever (Hog Cholera)?
A. It is indistinguishable clinically from African Swine Fever, but they are two totally different viruses.
B. It is a Pestivirus with only one antigenic type.
C. It is listed as OIE List A for its extreme economic impact
D. It is eradicated in the U.S., but exists in most countries of South America, as well as countries of Far East Asia such as Japan and Korea
E. All of the above are true
D.
Far East Asia EXCEPT Japan and Korea
Pathogenesis of Classical Swine Fever includes the following, EXCEPT:
A. Early depletion of CD1+, CD4+ and CD8+ cells
B. Macrophage activation, release of inflammatory cytokines
C. Vasculitis, thrombosis, hemorrhages
D. Release of TNF-alpha in lymph nodes and apoptosis of lymphocytes
E. Widespread leukopenia due to destruction of germinal centers of lymphoid tissue
E. It is a B cell deficiency due to destruction of
GERMINAL CENTERS of lymphoid tissue
Characteristic clinical features of Classical Swine Fever include: A. Purplish blotches on skin B. Diarrhea C. Urinary bladder hemorrhage D. Button ulcers in colon E. "Turkey egg" kidneys F. Abortion, stillbirth, mummified fetuses G. "Goose-stepping" gait H. All of the above
H all of the above
P DUBTAG
T/F:
West Nile Virus is a Flavivirus that is endemic in the U.S., with birds as reservoir hosts, mosquitoes as vectors, and horses and humans as incidental hosts.
True
Which of the following is TRUE regarding West Nile Virus?
A. There are at least 7 lineages, with 1 and 2 being important in humans
B. It has a high virulence in horses and causes encephalitis in most cases of transmission
C. Lineage 1A is most widespread in humans
D. Mosquito control is a main control method for the disease
B. It is mostly asymptomatic in horses, with only 8% of infections developing neuro signs
T/F:
Louping Ill is a mosquito borne Flavvivirus of sheep and red grouse in which at least 4 subtypes have been identified, and it is zoonotic.
False! It is TICK borne!!!!
Yes, it’s zoonotic
