Omar, aged 10 months, with no previous illness and formula fed, was progressing well until 12 hours ago when he developed diarrhoea and vomiting.

He has had eight watery stools without blood or mucous and it shows no signs of improving. He has vomited four times and has shown disinterest in taking his bottle. He was last weighed a week ago at 10kg and has passed urine in the last 2 hours.

Omar usually attends a day-care centre while his parents are at work. On examination Jack looks miserable but is well nourished and shows no signs of dehydration.

His vital signs are:

Temperature 38 C (oral)
Pulse 110/min
Respiration 40/min
BP 90/60