Infectious Diseases and Epidemiology
This section tests case definitions, incubation periods, isolation rules, contact tracing and the endemic infections of Kazakhstan: measles, brucellosis, tick-borne encephalitis, anthrax, viral hepatitis, tuberculosis and HIV.
Core rules
- Notifiable infections require immediate notification to the sanitary-epidemiological service: measles, diphtheria, polio, plague, anthrax, brucellosis, tick-borne encephalitis, tuberculosis, HIV and viral hepatitis.
- Measles: airborne, extremely contagious. Koplik spots precede a maculopapular rash that spreads from the face downwards, with cough, coryza and conjunctivitis. Isolation for four days after rash onset; vaccinate contacts within 72 hours.
- Brucellosis: unpasteurised dairy and livestock contact, undulant fever, arthralgia, hepatosplenomegaly; treated with doxycycline plus streptomycin or rifampicin for six weeks.
- Tick-borne encephalitis: endemic foci including the Almaty region, spring–summer season, biphasic fever and meningitis; prevention is vaccination, treatment supportive.
- Tuberculosis: sputum examination including GeneXpert, isolation of smear-positive cases, supervised treatment.
- Epidemiological investigation follows three links: source, route of transmission, susceptible host.
Worked example
A student returns from a regional visit with fever 38.5 °C, cough, coryza, conjunctivitis, and a rash starting behind the ears. Reasoning: the triad plus rash progression makes measles the working diagnosis. Actions are immediate isolation, notification, nasopharyngeal swab for polymerase chain reaction, and vaccination or immunoglobulin for susceptible contacts.
Traps
- Dismissing a febrile rash as allergy and delaying isolation.
- Waiting for laboratory confirmation before notifying.
- Forgetting to check the vaccination status of contacts.
- Missing brucellosis because the patient did not mention unpasteurised milk.