A 64 year old woman presented to hospital with fevers, chills, lethargy, and poor appetite. The symptoms had begun six days previously, when returning to the United Kingdom after a three week holiday visiting friends and family in Gujarat, India. She also felt nauseous, had a moderately severe bilateral frontal headache, and was constipated. Her only medical history was a thyroidectomy in 1982. Before travelling she received all relevant vaccinations, including hepatitis A and B and typhoid fever. She had not taken malarial prophylaxis. Her only regular medication was thyroxine 150 μg once a day.

On examination the patient seemed well. Her temperature was 37.3°C, pulse 80 beats/min regular, blood pressure 101/67 mm Hg, and respiratory rate 15 breaths/min. Her abdomen was soft but tender in the right upper quadrant, with no demonstrable organomegally; bowel sounds were normal.

Routine investigations showed a haemoglobin of 113 g/l, mean corpuscular volume 85 fl (78-100), white cell count 3.4×10⁹/l (4.5-11.0), neutrophils 2.1×10⁹/l (1.80-7.70), lymphocytes 0.99×10⁹/l (1.10-4.80), platelets 194×10⁹/l (140-450), C reactive protein 126 mg/l (<5), erythrocyte sedimentation rate 40 mm/h, sodium 136 mmol/l (135-145), potassium 3.6 mmol/l (3.5-5.1), creatinine 61 μmol/l (53-97), urea 3.1 mmol/l (2.5-6.7), alanine aminotransferase 68 U/l (0-55), alkaline phosphatase 242 U/l (40-150), total bilirubin 11 μmol/l (3-21), albumin 35 g/l (35-50), and corrected calcium 2.45 mmol/l (2.15-2.58).

Malaria parasites were not seen on three thick and thin blood films over three days. Chest radiography showed no abnormalities.