What are the clinical features of rotavirus?
- Reovirus, dsRNA, segmented, naked icosahedron
- Causes severe gastroenteritis: profuse watery diarrhea, dehydration, maladsorption
- Infants and children (adults usu. asymptomatic)
- >600,000 deaths/yr, mostly in developing world
- Peak incidence during winter
What is the life cycle of rotavirus?
- Genome is segmented, one gene each
- RDRP in the virion first transcribes mRNA
- Viral proteins are translated
- New virions and genome segments are synthesized in cytoplasm
- Virions assemble, bud into the rough ER
- Egress via exocytosis/cell lysis
- Virions mature in gut lumen, then infect more enterocytes or are shed in profuse diarrhea
What are the clinical features of influenza virus?
- Orthomyxovirus, (-) ssRNA, segmented, enveloped
- Acute respiratory illness; mainly wintertime
- “Uncomplicated”: upper and/or lower respiratory tract involvement, fever, headache, myalgia, weakness
- “Complicated”: 1° pneumonia caused by influenza, 2° bacterial pneumonia, mixed viral and bacterial pneumonia, muscle pain (myositis) and breakdown (rhabdomyelitis)
What is the life cycle of influenza virus?
- Genome is segmented, (-) ssRNA
- Genome segments traffic to nucleus for transcription and replication by RDRP
- Viral proteins and genome segments accumulate at the plasma membrane
- Virions assemble and egress by budding
- Neuraminidase (N antigen) releases virions from sialic acid on cell surface
- Virions are shed in respiratory droplets (coughs and sneezes)
What are the clinical features of HIV?
- Retrovirus, (+) ssRNA, 2 copies, enveloped
- Only humans infected
- Virus binds to CD4 and chemokine receptors on T cells and macrophages
- Depletion of these cells + chronic immune activation → immunodeficiency
- Symptoms include: fever, weight loss, headache, oral sores and thrust, lymphadenopathy, myalgia, rash, hepatosplenomegaly, nausea/vomiting
What are the stages of HIV disease?
- Exposure to virus (transmission)
- Primary HIV infection (acute phase)
- Latent period
- Early symptomatic HIV infection
- AIDS (CD4 cell count below 200/mm3)
- Advanced HIV infection (CD4 cell count below 50/mm3)
What is the life cycle of HIV?
- Virion fuses with the plasma membrane
Reverse Transcriptase enzyme (RT, included in the virion): (+) ssRNA genomes → dsDNA
- dsDNA genomes integrate into the host chromosome for life
- Host RNA Pol II transcribes mRNA from the integrated genome, which also serves as the genome that is packaged into new virions
- Viral proteins + 2 genomes bud from the plasma membrane
- Viral protease cleaves the capsid proteins, forming the final trapezoidal shape
- Virion maturation occurs outside the cell
What are the main symptoms of AIDS?
What types of HIV drugs are there?
- Nucleoside reverse transcriptase inhibitors (NRTIs)
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
- Protease inhibitors (PIs)
- Integrase strand transfer inhibitors (INSTIs)
- CCR5 antagonists
What are the goals of HIV treatment?