RNA Viruses & Retroviruses

By completing this question set, you will classify any RNA virus from genome type, segmentation, and envelope status, and predict its replication strategy. For picornaviruses, you will apply non-enveloped stability to explain fecal-oral transmission and predict which cell types each genus infects. You will explain why polio selectively destroys anterior horn motor neurons producing lower motor neuron signs. For influenza, you will explain HA and NA functions, apply the drift vs. shift framework to predict annual epidemic vs. pandemic scenarios, and explain why influenza B cannot cause pandemics. For measles, you will explain Koplik spots as a pathognomonic mucosal finding and trace the caudal progression of the morbilliform rash. For dengue, you will apply the antibody-dependent enhancement (ADE) mechanism to explain why secondary infection with a different serotype causes hemorrhagic fever. For HIV, you will map all seven replication steps to their corresponding drug class and explain why CCR5 M-tropic strains dominate early infection while CXCR4 T-tropic strains emerge late. You will explain why rabies incubation is longer with distal bite wounds and why death is invariable once symptoms begin. For HTLV-1, you will contrast the Tax oncoprotein with HIV pathogenesis to explain why HTLV-1 causes T-cell proliferation (ATLL) while HIV destroys T cells.