Exam 3: Retrovirus Flashcards
What are the genomic characteristics of a retrovirus?
Enveloped
Positive sense
ssRNA diploid
Reverse transcriptase is RNA dependent RNA polymerase
What viruses are related to neoplastic disease in poultry?
Avian leukosis/sarcoma virus
Reticuloendotheliosis virus
What is juror’s prudence of equine infectious anemia?
EIA is a regulated disease by state and federal agency
Equines, except for nursing foals, entering MS: an official copy of EIA test negative within 12 months
All equids, except nursing foals, that are participating in training, breeding, exhibition, moving, etc, require the original copy of a current negative EIA test
What kind of lymphomas are produced be FELV?
It goes everywhere in the body
Alimentary (gut-associated), multicentric (multiple LNs), thymic (mediastinal), or unclassified (skin, eyes, CNS)
What was the first retrovirus discovered?
Eqine infectious anemia
What was used to test for EIA?
Coggins test
What are the clinical signs seen with EIA?
Acute: fever, weight loss, anemia, edema, weakness, die 2-3 weeks
—EIA may test negative
Chronic: intermediated fever, lethargic, anorexia
Inapparent: most EIA tests are positive at this point, but no overt clinical signs
What is a provirus?
The genetic material of a virus is incorporated into, and able to replicate with, the genome of a host cell
Describe retrovirus replication
Virus enters host using receptor, reverse transcriptase copies the viral RNA genome into DNA. DNA integrates into host genome
Provirus becomes transcribed and translated for assembly of new viral progeny
What is bovine leukemia?
A persistent lifelong infection of deltaretrovirus which progresses to mutlicentric lymphosarcoma
What are strategies to control bovine leukemia?
Rigorous test and cull strategies
Remove positive cattle immediately
Isolated calves from infected dams are tested and then allowed to enter seronegative herd only if they remain seronegative at 6 months of age
Describe replication of defective retroviruses
Transmitted via infectious particles and can be expressed
It has a defective genome, so it requires a helper to replicate because they cannot synthesize their own envelope
Can lead to sarcoma, leukemia, or carcinoma after short incubation
What are the lentiviruses?
Equine infectious anemia
Ovine progressive pneumonia
