Varicella Zoster Virus Flashcards
Define the eclipse phase of infection.
Period from virus entry until new virions released.
Define the incubation period.
Interval between exposure and appearance of rash and sign.
Define the prodrome phase.
Non-specific symptoms appearing before specific features.
What is meant by the reproductive no.?
The number of new cases arising from single index case in population.
Give 2 features of the human herpes virus.
Large double-stranded DNA genome. Icosahedral capsid. Lipid envelope derived from host cell bearing virus-encoded glycoproteins.
How many types of herpes viruses are there?
8.
What are the two cycles of viral reproduction?
Lytic. Lysogenic cycle.
What is the lytic cycle?
The lytic cycle results in the destruction of the infected cell and its membrane.
What is the lysogenic cycle?
Lysogeny is characterized by integration of the bacteriophage nucleic acid into the host bacterium’s genome or formations of a circular replicon in the bacterial cytoplasm.
Primary infection.
Chickenpox (varicella).
The reactivation of chickenpox can result in what?
Shingles (painful skin rash).
Give 2 features of chicken pox.
Fever. Pharyngitis (sore throat). Malaise. Itchy/painful lesions.
Give 3 complications of varicella.
Haemorrhagic varicella (bleed into lesions). Pneumonia. Acute cerebellar ataxia (inability to coordinate balance). Encephalitis (brain becomes swollen). Secondary bacterial infection.
What is meant by horizontal hepatitis transmission?
Varicella spread by respiratory route.
What is meant by vertical hepatitis transmission?
Congenital infection of foetus in utero.
