Three crew members present with vomiting and diarrhoea within 12 hours of each other. As master, what are your suspicions, your management responsibilities, and your notification obligations?

A. OUTBREAK OF GASTROINTESTINAL ILLNESS — MANAGEMENT AND NOTIFICATION: SUSPICION: Three concurrent cases of vomiting and diarrhoea within 12 hours strongly suggests a common-source food or water outbreak — possible norovirus, Salmonella, or other food-borne illness. IMMEDIATE MANAGEMENT: (1) ISOLATE symptomatic crew from food preparation duties immediately; (2) STOP the suspected food or water source if identifiable; (3) Assess each case — rehydration is primary treatment (IMGS); hospitalisation criteria: dehydration, bloody diarrhoea, high fever, inability to maintain oral fluids; (4) IDENTIFY SOURCE: interview crew on recent meals, drinking water source, whether shore food was consumed; (5) Inform cook/galley to inspect food storage and preparation hygiene; (6) Enhance hand-washing protocols throughout ship — soap and water (not gel) is more effective for norovirus. NOTIFICATION OBLIGATIONS: (a) Flag state — under IHR 2005 (International Health Regulations), outbreaks of food-borne illness on board must be reported; (b) Next port health authority — advance notification so that quarantine assessment can be conducted on arrival; (c) Company DPA — for crew welfare and P&I purposes; (d) Maritime Declaration of Health (MDH): this is submitted on arrival at every port and must accurately reflect any illness on board. FALSIFYING MDH is a criminal offence under IHR 2005.

B. Treat the sick crew members with anti-diarrhoeal medication from the medical chest and do not report the outbreak. Port health notification is only required for cholera and other notifiable diseases — gastroenteritis does not require reporting.

C. Gastroenteritis cases at sea are a normal occurrence and require no special management beyond rest and fluids. There are no notification obligations for non-serious illness.

D. Report the outbreak immediately to the nearest MRCC and request evacuation of all three crew members. Any infectious disease on board is a health emergency requiring SAR assistance.

A. INTERNATIONAL MEDICAL GUIDE FOR SHIPS (IMGS) — MANAGEMENT USE: THE IMGS (3rd Edition, WHO/IMO publication): the authoritative reference for managing medical cases at sea. It is required under MLC 2006 Standard A4.1 and SOLAS Chapter III. STRUCTURE OF IMGS: (1) SYMPTOM-BASED approach — start from the patient's presenting complaint (chest pain, abdominal pain, breathing difficulty, altered consciousness), not from a diagnosis; (2) Assessment tools — vital signs guidance, AVPU scale, pain scoring; (3) Treatment protocols — appropriate to medications available in the ship's medical chest; (4) Evacuation criteria — specific signs that indicate when MEDEVAC must be requested; (5) Medication information — dosing, contraindications, side effects; (6) Specialist chapters — dental, eye, mental health. PROCESS: (1) Start with the patient's MAIN SYMPTOM — locate the corresponding chapter; (2) Follow the clinical assessment guide to narrow the differential; (3) Apply the treatment protocol; (4) Check the EVACUATION CRITERION — is this patient in the evacuate category? (5) Contact radio medical advice — provide: patient demographics, symptoms duration and onset, vital signs, current treatment. RADIO MEDICAL ADVICE: available 24/7 — in UK SAR area contact MRCC Falmouth, who connect to NHS Pathfinder or the relevant service. Document all medical consultations in the Medical Log.

B. The IMGS is only for use by ships' doctors. Officers without a medical qualification should not attempt diagnosis or treatment — radio for immediate evacuation instead.

C. The IMGS provides fixed protocols with no decision points. Follow the protocol for the suspected condition from beginning to end regardless of patient response.

D. The IMGS is an outdated publication replaced by the Ship Captain's Medical Guide (SCMG). Modern vessels are required to carry the SCMG, not the IMGS.

A. RADIO MEDICAL ADVICE — PROCESS AND INFORMATION REQUIREMENTS: CONTACT POINT: Telemedical Assistance Service (TMAS) — in UK SAR area, contact MRCC Falmouth (VHF Ch 16 / DSC Ch 70, or MF DSC). MRCC connects to the NHS emergency medical consultation service. Internationally — CIRM (Italy), Euro-TMAS (Germany), Falck (Denmark) also cover international waters. HOW TO CONTACT: transmit "PAN PAN MEDICO" on Ch 16 or via MF DSC. Provide: (1) Vessel name, position, course, speed; (2) Flag state; (3) Distance from nearest coast or port; (4) ETA nearest port; (5) PATIENT MIST REPORT: Mechanism/onset (chest pain started 20 minutes ago at rest), Injury/Illness (crushing chest pain, radiating left arm, sweating, pallor, score 8/10), Signs (BP 160/95, HR 105, RR 18, O2 Sats if monitor available), Treatment (aspirin 300mg given); (6) Available medications on board; (7) Crew medical training level. WHAT THE MEDICAL ADVISER WILL PRESCRIBE: likely: aspirin (if not already given), GTN spray if available, oxygen, ECG if available, rest and monitoring. EVACUATION DECISION: if symptoms are consistent with MI, TMAS will likely recommend MEDEVAC to nearest hospital with cardiac catheterisation capability. DOCUMENT: time contacted, medical adviser name, instructions given, patient observations throughout.

B. Transmit a Mayday on Ch 16 requesting immediate evacuation. A suspected heart attack is a life-threatening emergency requiring Mayday, not PAN PAN.

C. Treat the patient from the IMGS protocol for chest pain and do not contact radio medical advice unless the patient deteriorates. Medical advisers should only be contacted as a last resort.

D. Radio medical advice is only available in coastal waters within 200 miles. On the open ocean, radio medical advice is not available and the master must rely entirely on the IMGS.