Nellie Phillips contracted TB during the Second World War, when she lived in an internment camp in China. She has carried the disease bacillus since then but it lay dormant until last month.
Mrs Phillips complained of feeling unwell and was taken to Addenbrooke's Hospital in Cambridge. Doctors discovered a shadow on her lungs which was first thought to have been caused by bronchitis, but further tests showed she was suffering from TB.
Mrs Phillips has been cured by a course of medication and will soon return to Moorlands residential home near Royston.
A further 15 residents and 30 staff from the home who have been in close contact with Mrs Phillips are to be screened for TB. Tests will be carried out at Addenbrooke's from tomorrow. So far no one at Moorlands has shown any symptoms of the disease, which is transmitted through airborne water droplets.
Mrs Phillips was born and brought up in China, where her father designed railways and her mother was a missionary.
Following the Japanese invasion and the start of the Second World War, the family was held in an internment camp for six years. TB killed hundreds of thousands of people in China in that period, and disease was rife in the camps.
Roger Buttery, the district public health consultant, said: 'This is a very uncommon occurrence. East Anglia has the lowest incidence of TB in the country.
'However, it is normal for a person who has had TB as a child or teenager to see the infection re-activate itself when the immune system is less strong in old age.'
David Rushton, Cambridgeshire County Council social services area manager, said: 'We are taking all sensible medical precautions to reassure residents, their relatives and staff that the disease has not spread.'