• Direct contact
  • Infectious mononucleosis
  • Lymphogranuloma venereum
  • RSV, rhinovirus, Norwalk virus
• Droplet (>5 µm) (eg, coughing, sneezing)
  • Influenza
  • Meningococcal meningitis
  • Adenovirus, pertussis
• Airborne (<5 µm) (eg, aerosols, ventilation system)
  • Tuberculosis
  • Measles, chickenpox, smallpox
• Vector-borne
  • Mosquito: malaria, dengue, chikungunya, Zika virus
  • Tick: Lyme disease, RMSF