AT least 25 children at a primary school have been infected with tuberculosis.
As screening at Ballintemple National School in Cork continues, it has been revealed the number of pupils with the infection has risen dramatically.
Public health officials began screening over 220 children and their teachers last week after three pupils at the school were diagnosed with the disease.
The figure of 25 includes five children with active TB, while 20 have a latent form.
The Health Service Executive (HSE) said the disease can be cured with antibiotic treatment for at least six months.
Officials have yet to identify the source of the disease and the strain has not been identified.
The first case came to light a month after primary school holidays began, while notification of two further cases came in the past three weeks.
About 100 children at Ballintemple have yet to be screened. No case of full-blown TB has been detected in any staff member.
Parents have also been told the school is to re-open without any further delays.
The new term was due to start this week but was deferred until September 6 for screening at St Finbarr's Hospital in Cork, involving a simple skin test and a chest X-ray if required.
In 2007, 18 child cases and three adult cases were diagnosed at two Cork creches.
The incubation period from infection to a positive skin test for TB can be up to 12 weeks.
Up to August 7 this year, a total of 48 cases were notified in Cork. HSE Head of Health Protection Dr Kevin Kelleher indicated recently that the national screening programme for TB needed to be expanded.
A universal neonatal BCG vaccination programme was only re-introduced in Cork in October 2008. The vaccination had been withdrawn in 1972 over funding difficulties.
The vaccine has been shown to be most consistently effective against TB meningitis and blood-borne TB.
In 2006, 465 cases of TB (11 per 100,000 population) were notified to the Health Protection Surveillance Centre, a slight increase on the 2000-2005 rates.
TB is spread by droplets in the air. A person with infectious TB can expel TB germs into the air when they cough or sneeze.