Emerging Viruses & Arboviruses Flashcards
What is Canine parvovirus? How did it evolve?
It is closely related to feline panleukopenia virus. It mutated to be able to infect dogs (mutation in capsid protein).
What disease does CPV cause? Pathogensis?
Acute enteric virus. It targets rapidly dividing cells (e.g. crypt cells and cardiac myocytes in pups), virus ingested via oral route, replicates in lymphoid tissues, then generalised viraemia.
What are Influenza viruses? What are their 2 important type specific antigens? What diseases do they cause?
Influenza viruses are segmented RNA viruses. Haemagluttinin (HA) and Neuroaminidase (NA) antigens. Enteric in birds, Resp in everything else.
How many HA and NA type antigens are there?
16 HA, 9 NA.
How does HA aid Influenza pathogenesis?
HA aids attachment to cell. It is also cleaved using proteases into HA-1 and HA-2. Promotes fusion of virus and vesicle membrane (uncoating)
How does NA aid Influenza pathogenesis?
NA cleaves Sialic acid to aid virus release. (Stops virus binding to infected cell).
What are the 6 stages in Virus replication within a cell?
Attachment, penetration, uncoating, replication, assembly, release.
With relation to Influenza viruses, what is antigenic shift? Why are pigs usually ‘mixing vessels’?
Complete change in H or N subtype. This results in pandemics. Pigs can be infected with both avian and human virus, so they can reassort viral genomes. (One cell has to be infected with both)
What is a pandemic?
A disease prevalent over whole country or world.
With relation to Influenza viruses, what is antigenic drift?
Variation within H or N subtypes. Usually result in epidemics. This can be a change in host, or change in tropism.
What are Arboviruses?
Arthropod-borne viruses.
Give examples of arboviruses in the UK.
Louping Ill, Schmallenberg, AHSV, Bluetongue.
What is an ‘urban cycle’?
From athropod vector to humans and domestic animals.
What is a ‘sylvatic cycle’?
From athropod vector to wild, non-domestic cycle.
What is Louping Ill? What is it spread by? Clinical signs?
Aka Ovine Encephalomyelitis. Spread by Ixodes ricinus. CS = Biphasic fever, ataxia, paralysis.
