EHV-1

Question 1

How long is the virus shed for

Answer 1

3 weeks or more

Question 2

What is the incubation period

Answer 2

2-10 days

Question 3

What is the pathogenesis of the spread of EHV-1?

Answer 3

Virus attaches to and replicates in cells of nasopharyngeal epithelium and lymphoreticular tissues - infiltrate phagocytic cells which migrate into the circulation, resulting in viraemia (associated with mononuclear cells - primarily T lymphocytes - of the buffy coat)
Intracellular location protects it from inactivation by antibody and allows dissemination to other tissues - including the CNS
Vascular endothelium is the initial site of infection - transferred from circulating leukocytes without extra cellular phase

Question 4

What is the pathogenesis of EHV-1 myeloencephalitis?

Answer 4

Certain isolates have an endotheliotropism - vasculitis and thrombosis if arterioles and veins in brain and spinal cord cause impairment of blood flow and metabolic exchange leading to hypoxia and degeneration and necrosis, haemorrhage into predominantly white matter

Question 5

What are the key mucosal innate immune responses to EHV-1?

Answer 5

Induction of interferons (IFN-a)
Induction of IL-10
Induction of chemokines - CCL, CCL5 CCL1

Question 6

What are the key components of mucosal humoral immunity to EHV-1?

Answer 6

IgA and IgG 4/7