Final - Lecture 17 Flashcards
What is the single greatest determinant of economic costs of a FMD outbreak?
- immediate closure of all export mkts for Canada’s livestock and meat products
What is the virus that causes FMD?
Picornaviridae, Aphthovirus
What are 4 characteristics of Apthovirus?
- positive sense RNA virus
- 7 distinct serotypes
- 60 subtypes and periodic de novo generation of new subtypes
- not cross protective
What animals are primarily affected by FMD?
- cloven-hoofed domestic and wildlife animals
- swine, sheep, goats, cattle, water buffalo
Does FMD have a high mortality rate in young animals?
- yes
FMD is usually considers a disease that reflects…
‘economic development’
- absent: Australia, North America, Europe
- sporadic: South America
- endemic: Africa and Asia
Where does aphthovirus bind to?
- binds to integrin proteins on cell surfaces (docks onto the cell)
What are the 2 special requirements for a picornavirus?
- 100 nucleotide of the virus has a ‘cloverleaf’ structure that binds viral polypeptide 3C and host proteins to form a nucleoprotein complex: absolute requirement for viral replication
- Has an internal ribosome entry site; needed host ribosome’s to bind and translation of proteins
What are the ‘clever cell manipulations’ of Picornavirus?
- rapid shut-down of host cell protein translation
- leaves more materials (aa and ribosomes) to build more virus
- switching off pro- and anti-apoptotic signals to keep the cell living as long as possible
- reduces interferon and tumor necrosis factor response
When is Picornavirus inactivated?
- pH below 6.5 and above 11
- ultra-high pasteurization
- dry surfaces and UV light (sunlight)
Where can Picornavirus survive?
- milk, milk products, bone marrow, lymph glands, some meat products
Where will Picornavirus survive for weeks?
- organic rich material
How is FMD transmitted?
- respiratory aerosols - direct (animal) and indirect (man)
- fomites (contact) - boots, clothing, hands
- feeding: infected animal products
- others: AI, biological
What is the main source of FMD transmission?
- infected vesicle (blister)
What is the incubation period of FMD?
- develop clinical signs in 1-21 days