SummaryViral gastroenteritis is usually a mild, self-limiting illness. We report a case of a previously well 74-year-old woman who suffered a grave complication of this common condition, and caused a significant outbreak of illness amongst staff involved in her care. This case highlights the risks of Hospital Acquired Infection and raises important infection control issues. It illustrates the hazards associated with exposure to potentially infectious secretions and presents a clear message to medical and nursing staff involved in the care of the acute surgical emergency.Keywords Gastroenteritis. Infection control. A 74-year-old woman was admitted to the Emergency Department of our hospital in the early hours of the morning with a suspected ruptured abdominal aortic aneurysm. She had clear risk factors for an aneurysm: she was hypertensive, had ischaemic heart disease and had a strong family history (both siblings had died suddenly following ruptured aneurysms). She had a short history of severe epigastric pain radiating through to her back associated with dizziness, near syncope and vomiting. Although there was a suggestion of some gastrointestinal upset during the preceding 24 h, the surgical diagnosis was one of abdominal aortic aneurysm. On arrival, she was unwell and clearly shocked. Her blood pressure was 100 ⁄ 60 mmHg, her pulse rate 126 beats.min )1 and her SpO 2 91% on maximal facemask oxygen. Her presenting hypotension responded initially to a 1000-ml fluid bolus, but the pain persisted and she remained tachycardic and in respiratory distress. Her abdomen was rigid and distended, and it was thought that her respiratory distress was partly due to this. She was transferred to the operating theatre for an emergency laparotomy whilst being resuscitated. Assessment by the consultant vascular surgeon in the operating theatre following initial fluid resuscitation raised some doubts about the initial diagnosis of ruptured aortic aneurysm; however, it was clear that there was some serious intra-abdominal pathology that required definitive diagnosis and treatment. Results of initial blood tests were not available at this time. After placement of a wide bore central line and an arterial line, anaesthesia was induced with 250 lg fentanyl, 2 mg midazolam and 75 mg thiopental, followed by 100 mg succinylcholine. Her trachea was intubated with some difficulty with a 7-mm cuffed tracheal tube, and thereafter anaesthesia was maintained with isoflurane in oxygen ⁄ air. At laparotomy, the team was surprised to find no intra-abdominal pathology at all. Her clinical condition remained unstable and she required extensive intravenous fluids and vasopressor support, initially in the form of boluses of 1 mg metaraminol but later an epinephrine infusion. Her ventilation was satisfactory, with normal airway pressures and acceptable gas exchange.In view of the negative operative findings but her poor and deteriorating clinical condition, the available history and investigation results were re-examined. The patient had been taken t...