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Questions and Answers
What are the outcomes of viral replication?
What are the outcomes of viral replication?
What are the 3 important steps in viral pathogenesis?
What are the 3 important steps in viral pathogenesis?
Virus entry into the host, primary virus replication, virus spread within the host
Vasculitis leads to __________ necrosis in dermal endothelium.
Vasculitis leads to __________ necrosis in dermal endothelium.
ischemic
Match the following animals with the respective pox virus:
Match the following animals with the respective pox virus:
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Can pox viruses affect dogs and cats?
Can pox viruses affect dogs and cats?
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Study Notes
Viral Diseases
- Viruses are programmed to replicate endlessly if all growth factors, metabolic needs, and microenvironments are met.
- Viral pathogenesis involves several steps: virus entry, primary replication, spread within the host, cell tropism, cellular injury, immune response, clearance or persistence, and shedding and transmission.
Viral Replication Outcomes
- Cell death
- Persistence/latency
- Cell proliferation
- Neoplastic transformation
Poxviruses
- Poxviruses cause a group of diseases affecting domestic, wild, and laboratory animals, as well as humans.
- There are 8 genera of poxviruses:
- Orthopoxvirus
- Avipox
- Suipoxvirus
- Capripoxvirus
- Leporipoxvirus
- Molluscipoxvirus
- Yatapoxvirus
- Parapoxvirus
Parapoxvirus
- Causes pox diseases in animals, including:
- Orf virus (ORFV)
- Bovine papular stomatitis virus (BPSV)
- Pseudocowpox virus (PCPV)
- Squirrel parapoxvirus (SPPV)
Capripoxvirus
- Causes:
- Sheeppox virus (SPPV)
- Goatpox virus (GTPV)
- Lumpy skin disease virus (LSDV)
Pathogenesis of Poxviruses
- Infection by direct virus contact or inhalation/ingestion
- Virus entry into the host, followed by systemic leukocyte trafficking
- Infection and multiplication in:
- Dermal endothelium, leading to vasculitis and ischemic necrosis
- Epidermal epithelial cells, leading to hyperplastic and necrotizing lesions (pox-lesions)
Lesions
- Macule (erythematous macule): a change in surface color, without elevation or depression
- Papule: a circumscribed, well-defined, solid elevation of skin
- Vesicle (small blister): a circumscribed, epidermal elevation containing fluid
- Pustule: a small, circumscribed elevation of the skin containing pus
- Scabs and scars: result from healing of the pustules by granulation tissue
Gross Lesions
- Cutaneous pox lesions, most easily observed on wool-free or hair-free areas
- In sheeppox and goatpox: systemic disease with lesions in the lungs, liver, and other organs
Microscopic Lesions
- Acanthosis and ballooning degeneration of the stratum spinosum
- Dermal necrosis
- Severe vasculitis (thrombosis) with ischemic necrosis
- Dermal perivascular lymphocytic aggregations
- Presence of Guarnieri bodies (B-type inclusions) and sheeppox cells (cellules claveleuses' of Borrel)
Lumpy Skin Disease
- Caused by Capripoxvirus
- Affects primarily cattle and buffaloes
- Pathogenesis pathway: infection by insect vector, direct contact, aerosols, and fomites
- Clinical signs: fever, multiple well-circumscribed skin nodules, generalized lymphadenopathy, marked weight loss, profuse drooling, and oculonasal discharge
- Lesions: skin nodules, lymphadenopathy, and systemic lesions
Fate of the Nodules
- Some nodules resolve completely, leaving a deep ulcer
- Some nodules fail to separate but become indurated and persist as hard intradermal lumps
- Secondary bacterial infections may develop in the necrotic nodules
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Description
This quiz covers the fundamentals of viral diseases, including the replication process and pathogenesis, in the context of veterinary medicine.