Measles Virus Structure and Initial Infection

• Measles virus = hull of proteins + RNA + reproduction proteins
• Cannot reproduce independently, requires host cell
• Entry points: nose, mouth, eyes
• Infection starts in lungs
• Targets macrophages (body's first defense line in lungs)
• Virus reprograms cells into virus production centers

Immune System Response - First 10 Days

• Natural killer cells patrol body, check for infections
• Order infected cells to commit suicide
• Process so effective that infection unnoticed for ~10 days
• Macrophages fight and die, then alert dendritic cells (immune system's brain)

Measles' Trojan Horse Strategy

• Virus infects dendritic cells directly
• Uses infected dendritic cells as Trojan horse to penetrate deeper
• Infected cells travel to lymph nodes to "alert" other immune cells
• Virus spreads to virgin T and B cells, infecting them
• Attacks the very immune system designed to fight it

Systemic Spread and Symptoms

• Lymph system spreads virus everywhere
• Virus enters bloodstream, infects cells while traveling
• Infected organs: spleen, liver, intestines, lungs
• Symptoms: high fever, headache, sickness, bronchitis, rash
• Second lung attack kills countless cells, wipes out defense systems
• Patient coughs out millions of measles viruses

Contagion and Secondary Infections

• 90% infection chance for unvaccinated contacts
• Without lung protection, other bacteria/viruses enter easily
• Secondary infections cause pneumonia (most common death cause)
• Immune system seriously wounded, protective systems disrupted
• Virus spreads to skin (visible measles rash appears)

Brain Infection Risk

• Measles virus can reach brain, cause brain infection
• Brain infection mortality rate: 20-40%
• Potential for long-term damage

Recovery Process

• Body fights back aggressively
• Surviving dendritic cells activate anti-virus forces
• Plasma cells produce billions of antibodies
• Killer T cells flood body, kill infected cells
• Recovery takes 2-3 weeks typically
• Immune system weakened for weeks/months post-recovery
• Body vulnerable to other diseases during recovery
• Survivors gain lifelong immunity

Global Statistics and Vaccination

• 84% of humans vaccinated against measles
• 122,000 deaths from measles in 2014
• Some cannot vaccinate: too young, chemotherapy patients, HIV patients, vaccine allergic
• These vulnerable populations need herd immunity protection

Vaccination Benefits and Myths

• Measles vaccination: safe, cheap, available
• No benefits from contracting measles
• Measles doesn't strengthen immune system
• Disease isn't "more natural"
• Not vaccinating puts own child and others at risk