2. Olds (2nd exam) Flashcards
Characteristic lesions or clinical signs of infection with the following viruses:
(a) Poxviridae
(b) Circoviridae
(c) Herpesviridae
(d) Retroviridae
(e) Rhabdoviridae
(f) Paramyxoviridae
a) Skin lesions
b.)Nasal discharge
c) Respiratory
d) Immune-mediated, nasal discharge
e) Neurological
f) Respiratory
(a) What 3 cells do Parvoviruses target and
(b) what is their common characteristic?
(a)
1. Crypts of Lieberkuhn
2. hematopoietic precursor cells
3. lymphopoietic precursor cells
4. lymphocytes
(b)
They are continuously dividing.
Are the following viruses stable or unstable in the environment?
(a) PRRSV
(b) CDV (c-f)
(a) PRRSV➡️arteri (env)➡️unstable
(b) CDV➡️paramyxo (env)➡️unstable
(a) Draw how Paramyxoviruses form multinucleated giant cells.
(b) How to multinucleated giant cells help in immune evasion?
(a) Cells infected with paramyxoviruses express F-proteins on their plasma membrane. These F-proteins facilitate fusion of the infected cell with adjacent healthy cells, leading to the formation of a multinucleated giant cell or syncytium.
(b) Multinucleated giant cells help paramyxoviruses evade the immune system because they allow the virus to infect other cells without exiting already infected cells.
Draw and describe the replication process of Paramyxovirus
Viral ligand (3)
Cell receptors (2)
Entry?
DRAW?
Viral ligand (3)
1. HG
2. H
3. G
Cell receptors (2)
1. CD150
2. Epithelial cell receptor nectin-4
Entry: fusion of envelope & cell PM; F protein
- P & L initiates mRNA synthesis
- Cytoplasmic replication
- Budding from plasma membrane (PM)
What are the 3 functions of reverse transcriptase in Retrovirus infections?
● RNase
● RdDp
● DdDp
What is the outcome of PPV infection on gestation at:
a. 25 days
b. 50 days
c. 105 days
Differ at
● 0-6 days
● 6-35 days
● 35-70 days
● 70-114 days
(a) 25 days - death and reabsorption
(b) 50 days - death and mummification
- Already developed bones, so cannot be reabsorbed by the body.
(c) 105 days - immune response usually leads to survival/stillbirth
What are 3 characteristic lesions of Feline Herpesvirus 1?
- Upper respiratory
- Ocular/conjunctivitis
- Erosion and ulceration of mucosal surfaces
How does CPV2 reach its target cells (up to organs)?
1) RME entry into cell
2) Virus enters nucleus, and DNA replication & assembly occurs
3) Virus uses polymerases if the cell in order to replicate its DNA, which are abundant in rapidly dividing cells on S-phase of cell cycle
4) Formation of ds DNA intermediates
5) Complex rolling circle DNA replicaion in cell nucleus
Draw the replication of typical herpesvirus genes.
● IE proteins
● E proteins
● L proteins
General steps:
1) gp spikes (ligand) binding to 1 or more cell receptors
2) Envelope fuses with cell membrane
3) Entry and uncoating in cytoplasm
4) Entry viral genome into nucleus
5) Shut-down of host cell marcomolecular synthesis
6) Protein (IE, E, L) and na synthesis
7) Maturation (primary & secondary envelopment)
8) Release by exocytosis
Give & explain 3 classes of mRNA proteins.
α (immediate early) proteins – initiates transcriction of beta genes
β (early) mRNAs,
β (early) proteins – suppresses transcription of further α mRNAs
γ (late) proteins – structural proteins
Draw and describe how TGEV (Transmissible gastroenteritis virus) causes secretory diarrhea
CORONA
- Oral ingestion results in viral replication in the epithelial cells of the small intestinal and colonic villi…
- Resulting in degeneration of enterocytes –> leading to shortening of the villi.
- This causes clinical manifestations of the disease including watery diarrhea.
Differentiate antigenic shift and antigenic drift.
● Antigenic shift - virus undergoes a sudden change in genetic makeup➡️new strain
● Antigenic drift - virus undergoes a gradual change in genetic makeup
Genetic shift vs. Genetic drift
Shift: Genetic reassortment occurs between viruses within each genus or serogroup (genetic shift),
Drift: along with mutation of individual genes (genetic drift).
