Complex sentence: Since this date, there have been a total of 54 more cases in North America and Europe, nine of which were successfully treated., quotes 49 cases, but does not include the May 2009 deaths of two calves at Whipsnade Zoo in this calculation.
Split into simpler sentences: Since this date, there have been a total of 54 more cases in North America and Europe, nine of which were successfully treated. The May 2009 deaths of two calves at Whipsnade Zoo were not included in this calculation.