Infectious Diseases, Epidemiology and Immunoprophylaxis
Infectious diseases
Know the clinical picture, diagnosis, and treatment of common infections: respiratory (influenza, COVID-19, tuberculosis), gastrointestinal (salmonellosis, dysentery, hepatitis A), blood-borne (hepatitis B/C, HIV), and vector-borne (Lyme disease). Understand isolation precautions and notification requirements.
Epidemiology
Core concepts: source of infection, transmission route, susceptible host; epidemic process; incidence versus prevalence; outbreak investigation; and the principles of disinfection and sterilization. Know the national immunization schedule and cold-chain requirements.
Immunoprophylaxis
Understand vaccine types (live, inactivated, toxoid, subunit), contraindications, and adverse events. Recognize that most mild acute illness is not a contraindication to vaccination.
Traps
- Confusing incidence (new cases) with prevalence (all cases).
- Misclassifying transmission routes (airborne vs droplet vs contact).
- Applying adult isolation rules to pediatric settings.
Rule of thumb
For any outbreak question: identify the source, the transmission route, and the susceptible population, then choose the intervention that breaks the chain at the weakest link. For vaccination: check the schedule and true contraindications before deciding.
Worked example
A cluster of gastroenteritis after a shared meal: the correct approach is to identify the common source, interview cases, collect food and stool samples, and implement hygiene measures - not to start antibiotics for all contacts.