🦠 Rheumatic Fever Prevention Simulator

Strep Throat — Group A Streptococcus Colonizes the Pharynx

Placeholder: a common sore throat, but one bacterium can trigger lifelong heart damage.

• 600M+: GAS pharyngitis cases/yr (global) (placeholder estimate)
• 5–15: Peak age group (school-age children)
• 2–5 days: Incubation period (exposure to symptoms)
• Day 0: Symptom onset (sore throat, fever, exudate)

What is Group A Strep

Placeholder text: gram-positive cocci in chains, spreads by droplets.

The M-protein virulence factor

Placeholder text: surface M-protein resembles human cardiac myosin.

Placeholder highlight: molecular mimicry starts here, at the bacterial surface.

Why untreated strep matters

Placeholder text: most cases resolve, but a fraction trigger autoimmunity.

Antibiotic Treatment Window — Day 0 to Day 9

Placeholder: a short course of penicillin, started early enough, prevents rheumatic fever entirely.

• Day 9: Window closes (post symptom onset)
• Penicillin: First-line drug (or amoxicillin)
• ~100%: ARF prevention if treated in window (placeholder figure)
• 10 days: Typical course length (oral penicillin V)

Why day 9 matters

Placeholder text: antibody buildup against M-protein takes about this long.

Clearing the bacteria

Placeholder text: antibiotics eliminate GAS before cross-reactive antibodies form.

Placeholder highlight: treating late still helps, but risk climbs day by day.

Access and equity

Placeholder text: population coverage determines how many windows are missed.

Molecular Mimicry — Antibodies Turn Against the Heart

Placeholder: anti-strep antibodies mistake cardiac tissue proteins for bacterial M-protein.

• M-protein / myosin: Shared epitope (structural similarity)
• ~2–3 wks: Antibody buildup time (after untreated infection)
• Valve endothelium: Primary target tissue (mitral most common)
• T & B cells: Immune cells involved (cross-reactive clones)

The cross-reaction mechanism

Placeholder text: shared epitopes fool the adaptive immune system.

Why the heart valve

Placeholder text: valve tissue proteins closely resemble bacterial antigens.

Placeholder highlight: this is autoimmunity, not ongoing infection.

Timing versus treatment

Placeholder text: earlier antibiotics mean fewer antibodies ever form.

Acute Rheumatic Fever — Joints, Heart, and Brain

Placeholder: when the window is missed, inflammation can spread through the whole body.

• ~75%: Migratory arthritis (of ARF cases, placeholder)
• ~50–70%: Carditis (of ARF cases, placeholder)
• ~10–30%: Sydenham chorea (of ARF cases, placeholder)
• 2–4 wks: Onset after strep (latency period)

Jones criteria overview

Placeholder text: diagnosis combines major and minor clinical criteria.

Carditis and valvulitis

Placeholder text: inflamed valve leaflets thicken and may leak.

Placeholder highlight: carditis is the only ARF finding that can leave permanent damage.

Chorea and joint involvement

Placeholder text: involuntary movements and migrating joint pain follow.

Outcome Comparison — Prevented Disease vs Rheumatic Heart Disease

Placeholder: the same bacterium, two very different futures for the heart valve.

• ~40M: RHD prevalence (global) (placeholder estimate)
• ~300K: Deaths per year (placeholder estimate)
• <$1: Cost of penicillin course (placeholder figure)
• $10K+: Valve surgery cost (placeholder figure)

Treated-in-window pathway

Placeholder text: bacteria cleared, no antibodies, healthy valve preserved.

Missed-window pathway

Placeholder text: recurrent ARF episodes compound valve scarring over years.

Placeholder highlight: secondary prevention (monthly penicillin) still protects after a first episode.

Population-level prevention

Placeholder text: coverage rate drives cumulative cases across a population.