THE NUMBER of tuberculosis cases at a Midlands school has now reached 50 with the confirmation of another 18 on Wednesday. Some 44 students at Crown Hills community college in Leicester are now being treated with antibiotics after they showed early signs of the disease. Four famil members and two teachers are also infected. The outbreak - thought to originate with a single pupil - is the worst in Britain for 20 years, but health officials believe that it is now under control. None of the 18 new cases was bad enough to require hospital treatment.