Microbiology – Virology (Detailed with Clinical
Correlation)
Virology is the study of viruses, which are obligate intracellular parasites. They require host cells to
replicate and cause a wide range of diseases.
Major Virus Families:
Family Virus Disease Incubation Transmission Treatment
Herpesviridae HSV, VZV Herpes, Chickenpox 2–12 days Contact Acyclovir
Orthomyxoviridae Influenza Flu 1–4 days Droplets Oseltamivir
Paramyxoviridae Measles, Mumps Measles, Mumps 7–14 days Droplets Supportive
Picornaviridae Polio, HAV Polio, Hep A 7–21 days Fecal-oral Supportive
Retroviridae HIV AIDS Weeks–years Blood/sexual ART
Hepadnaviridae HBV Hepatitis B 1–6 months Blood Antivirals
Flaviviridae Dengue, HCV Dengue, Hep C 3–14 days Mosquito/blood Supportive/DAA
Rhabdoviridae Rabies Rabies 1–3 months Animal bite Vaccine + Ig
Coronaviridae SARS-CoV-2 COVID-19 2–14 days Droplets Supportive
Virus Structure:
Genetic material: DNA or RNA
Capsid: Protein coat
Envelope: Lipid layer (in some viruses)
Viral Replication:
Attachment → Entry → Replication → Assembly → Release
Occurs inside host cells
Clinical Correlations:
HIV destroys CD4 cells leading to immunodeficiency
Dengue causes hemorrhagic fever
Rabies leads to fatal encephalitis
COVID-19 affects respiratory system
Prevention:
Vaccination (e.g., measles, hepatitis)
