1. A 30-year-old man travelling to an endemic area asks how to prevent cholera. What is the most effective preventive measure?

• Vaccination with oral cholera vaccine
• Prophylactic antibiotics
• Boiling drinking water and improving sanitation
• Avoiding raw fruits and vegetables

Answer: Boiling drinking water and improving sanitation

Ensuring clean water supplies and proper sanitation is crucial to preventing cholera. Vaccination supports these efforts but is secondary.

2. A 25-year-old man presents with fever, abdominal cramps, and diarrhoea. Stool culture reveals Campylobacter jejuni. What is the most appropriate first-line treatment?

• Oral azithromycin
• Oral ciprofloxacin
• Oral metronidazole
• Rehydration therapy alone

Answer: Rehydration therapy alone

Uncomplicated Campylobacter enteritis typically resolves with supportive care (fluid/electrolyte replacement). Antibiotics are for severe or prolonged cases.

3. A 50-year-old man presents with trismus and muscle spasms after stepping on a rusty nail. He has not received a tetanus booster in over 20 years. What is the most appropriate immediate management?

• Administer human tetanus immunoglobulin (TIG)
• Start oral metronidazole
• Administer tetanus toxoid vaccine
• Perform wound debridement and monitor

Answer: Administer human tetanus immunoglobulin (TIG)

TIG provides passive immunity by binding circulating tetanus toxin. Antibiotics, wound care, and vaccination are also used, but TIG is urgent first.

4. A 35-year-old woman presents with fever, fatigue, and an expanding erythematous rash with central clearing after a tick bite. What is the most appropriate next step?

• Start oral doxycycline empirically
• Perform serological testing for Borrelia burgdorferi
• Administer a single dose of ceftriaxone
• Observe and monitor for progression

Answer: Start oral doxycycline empirically

Early localized Lyme (erythema migrans) is treated with doxycycline without waiting for serologic confirmation.

5. A 10-year-old unvaccinated boy presents with fever, sore throat, and a thick grey membrane over the pharynx. What is the most appropriate next step?

• Administer diphtheria antitoxin
• Prescribe oral penicillin
• Perform urgent tracheostomy
• Isolate the patient and monitor respiratory status

Answer: Administer diphtheria antitoxin

Diphtheria antitoxin rapidly binds circulating exotoxin. Antibiotics and supportive care follow.

6. What is the most common complication of untreated MRSA bacteraemia?

• Endocarditis
• Osteomyelitis
• Septic arthritis
• Pulmonary abscesses

Answer: Endocarditis

MRSA bloodstream infections frequently seed heart valves, leading to endocarditis if not promptly treated.

7. A 30-year-old man develops diarrhoea, fever, and abdominal cramps after eating undercooked chicken. Stool culture confirms Salmonella. What advice should be given about preventing transmission?

• Wash hands thoroughly after using the toilet
• Avoid close contact with others until symptoms resolve
• Start a course of ciprofloxacin to prevent transmission
• Use alcohol-based hand sanitiser instead of soap and water

Answer: Wash hands thoroughly after using the toilet

Hand hygiene is the single most effective measure to curb faeco-oral transmission of Salmonella.

8. A 40-year-old man presents with fever, headache, and a maculopapular rash after travelling to Southeast Asia. He recalls being bitten by fleas. What is the most likely diagnosis?

• Typhoid fever
• Murine typhus
• Scrub typhus
• Leptospirosis

Answer: Murine typhus

Murine typhus is transmitted via fleas (often from rodents), typically presenting with fever, headache, and rash.

9. What is the primary predisposing factor for oral candidiasis?

• Immune suppression
• High carbohydrate diet
• Smoking tobacco
• Use of antihistamines

Answer: Immune suppression

Oral thrush typically arises in immunocompromised individuals or those on inhaled steroids without mouth rinsing.

10. A 12-year-old boy presents with fever, pain, and swelling in the left leg. Blood tests show elevated CRP and ESR. X-ray is normal, but MRI shows bone marrow oedema. What is the most likely diagnosis?

• Osteomyelitis
• Cellulitis
• Septic arthritis
• Bone tumour

Answer: Osteomyelitis

MRI is sensitive for early osteomyelitis, detecting marrow oedema before X-ray changes appear.