This comprehensive course explores the fascinating world of viruses, the enigmatic infectious agents that blur the line between living and non-living entities. We'll examine their classification, structure, replication, and interaction with host cells, equipping you to understand these pervasive pathogens.

• Classification Systems: We begin by examining the various systems used to classify viruses, based on factors like genome type (DNA/RNA, single/double stranded), structure (enveloped/non-enveloped), and replication strategy (lytic/lysogenic). Explore the International Committee on Taxonomy of Viruses (ICTV) and its role in standardizing viral classification.
• Particle Structure and Stability: Unravel the intricate architecture of viral particles, including capsids (protein shells), envelopes (lipid bilayers), and nucleocapsids (complexes of viral nucleic acid and proteins). Learn about factors that influence viral stability in the environment and within host organisms, such as capsid composition, pH, and temperature.
• Genome Diversity: Discover the remarkable diversity of viral genomes, encompassing single-stranded (ss) and double-stranded (ds) DNA or RNA molecules. Explore the unique features of each type and their implications for replication and evolution (e.g., ssRNA viruses with high mutation rates).
• Viral Replication: Demystify the fascinating process of viral replication, from attachment and entry into host cells to viral gene expression, protein synthesis, assembly of new viral particles, and their release. Explore the differences in replication strategies between various virus types, such as the lytic cycle (immediate cell lysis) and the lysogenic cycle (viral genome integration into host DNA).
• Cell-to-Cell Movement: Learn about the mechanisms viruses employ to move from one infected cell to another, ensuring their continued propagation. Explore different modes of cell-to-cell movement like budding (protrusion and pinching off) and cell-to-cell fusion (creation of multinucleated cells).
• Viral Transmission: Uncover the diverse routes by which viruses are transmitted between hosts, including direct contact, airborne droplets, bodily fluids (blood, saliva), and vectors like insects (mosquitoes) and animals (ticks).
• Viral Genetics: Explore the unique features of viral genomes and their susceptibility to mutation. Learn how mutations can contribute to viral evolution, emergence of new strains, and potential drug resistance.
• Virus-Host Interactions: Delve into the intricate dance between viruses and their hosts. Explore how viruses manipulate host cell machinery for their own replication (e.g., hijacking ribosomes for protein synthesis) and how host immune systems attempt to defend against viral invasion (e.g., antibody production and immune cell activation).
• Electron Microscopy: Discover the power of electron microscopy in visualizing the morphology and structure of viral particles at high magnification.
• Serology and Immunochemistry: Learn how serological techniques like enzyme-linked immunosorbent assay (ELISA) can be used to diagnose viral infections by detecting antibodies produced in response to the virus.
• Molecular Methods: Explore the power of molecular methods like hybridization (identifying specific viral sequences), PCR (amplifying viral DNA), and RT-PCR (reverse transcription PCR for RNA viruses) for detecting and characterizing viral nucleic acids.
• Viral Epidemiology: Unravel the patterns of viral outbreaks and how factors like population density, human behavior, and vaccination coverage influence their spread. Explore strategies for disease surveillance (tracking outbreaks) and outbreak control (containment measures).
• Plant, Animal, and Bacterial Viruses: Focus on specific examples of viruses that impact different kingdoms of life, including the cocoa swollen shoot virus (plant), HIV and bird flu virus (animals), and bacteriophages (bacteria). Explore their unique characteristics, disease processes, and potential control measures (e.g., plant breeding for resistance, antiviral drugs, vaccines).