VIRUSES

VIRUSES

1. OBLIGATE INTRACELLULAR PARASITES

   • STRUCTURE
     • VIRAL ENVELOPE
       • helps in infection and infiltration of host cells
       • budded from host cell membrane
       • contains glycoprotein spikes
     • CAPSID
       • protects genome of virus and may be involved in infection
       • icosahedral
       • complex
       • helical
     • GENOME
       • DNA
       • RNA
         • positive or negative strand. negative acts as mRNA
   • CLASSIFICATION
     • infected organism
     • genome
       • RETROVIRIDAE
         • contain dsRNA and reverse transcriptase
           • RNA - cDNA
     • shape
     • envelope presence
     • disease caused

2. HUMAN IMMUNODEFICIENCY VIRUS

   • STRUCTURE OF RETROVIRUS
     • two positive RNA strands
     • enveloped virus
       • gp120 and gp41
     • viral enzymes present
       • protease
       • integrase
       • reverse transcriptase
   • LIFE CYCLE
     • ATTACHMENT
       • targets CD4 T cells
         • gp120/gp41 mediate attachment
     • PENETRATION
       • reverse transcriptase forms cDNA
         • integrase inserts cDNA into host DNA
     • REPLICATION
       • occurs when T cell is activated
     • ASSEMBLY
       • mediated by various genes and protease
     • PHASES OF INFECTION
       • ACUTE PHASE
         • flu-like symptoms
       • CHRONIC PHASE
         • progressive decrease in CD4 cells
       • AIDS
         • less than 200 CD4 cells/mm3
         • COMPLICATIONS OF AIDS
           • opportunistic infections
             • candidiasis
           • neurological diseases
             • AIDS dementia complex
           • malignant tumors
             • Kaposi's sarcoma
           • STIGMA
             • social
             • verbal
             • physical
             • institutional
   • HIV1 more virulent and infectious than HIV2
     • TRNASMISSION
       • vertical transmission
         • placenta
         • during bith
         • breastfeeding
       • horizontal
         • blood infusions or needles
         • unprotected sex
         • tissue transplants
   • DIAGNOSIS
     • screening test
       • ELISA
     • confirmatory test
       • western blot and PCR
   • TREATMENT
     • PMTCT
     • PrEP
     • PEP
     • Antiretroviral durgs
       • NNRTIs
       • NRTIs
       • PIs
       • fusion inhibitors
       • integrase inhibitors