Viral pathogenesis 2

===Lecture Details===
Hans Netter; Week 6 MED1022; Microbiology
===Lecture Content===
Picornaviridae are ssRNA, non enveloped capsid that is polyprotein encoded. It contains Enteroviruses (polio, coxsackie, enterovirus), Rhinovirus, Hepatovirus (hep A). 90% of polio is asymptomatic (infection limited to oropharynx and gut), spread to CNS causes motor neuron destruction. Oral poliovaccine prevents spread to nervous system. Produces a response in mucus lining of intestine preventing infection/multiplication inside the gut. Passive immunisation can occur from shedding. Can cause paralysis. Inactivated vaccine cannot cause paralysis.
Retrovirus is linear, ssRNA, has monomers held together by hydrogen bonds. Are RNA polyadenylated, covered with a cap. HIV infects CD4 cells, in initial, acute phase CD4 conc decreases, virion increases; when immune system mobilises virus concentration decreases and CD4 count recovers. Chronic/asymptomatic phase has slow CD4 fall. Symptomatic phase is at 200-500 CD4 cells/ml. Kaposi's sarcoma is herpesvirus type 8 in immunocompromised.
===Readings===