Three students at Palmerston North Boys High School will be tested for tuberculosis following the diagnosis of a schoolmate with the disease.
The boy, a Year 13 pupil, contracted TB during an outbreak of the disease at the school in 2006 and now he has developed it.
The school's rector, Tim O'Connor, says the case bears a resemblance to the start of the 2006 outbreak, in which 235 people were infected and 15 developed the disease.
Dr Jill McKenzie of the MidCentral District Health Board says the boy was diagnosed at an early stage and is no longer considered to be infectious.
She says those at highest risk of having contracted the disease have been tested and so far there is no evidence of contagion.
Mr O'Connor says the boy's family have already tested negative but three other students from the school will be tested for TB.