A five-year-old girl has died from Strep A - taking the total number of fatalities to nine.
The child became severely ill last week and was being treated at the Royal Belfast Hospital for Sick Children.
Parents of P1 to P3 pupils at Black Mountain Primary School were sent a letter by the Public Health Agency.
The confirmed a child had been diagnosed with a severe form of the bacterial infection.
Pupils were told the attend a clinic or see their GP to receive antibiotics.
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The BBC reports the girl had been moved to intensive care before she died.
Schools Minister Nick Gibb told Sky News "it's tragic for the parents" of those children who have died.
"What the UKHSA are doing is they are working closely with the schools involved and giving very specific advice to those schools which may involve use of penicillin and so on," he said.
"They will have more advice about that and they are providing more general advice to parents which is to look out for symptoms, so sore throat, fever, high temperature and also a red or raised rash on the skin."
It comes after a child from Morelands Primary School in Waterlooville, Hampshire, was reported to have died yesterday.
The outbreak has also seen the deaths of Muhammad Ibrahim Ali, 4, in High Wycombe, Buckinghamshire, and Hanna Roap, 7, in Penarth, Wales.
A 12-year-old student from Lewisham, London has also died, their school confirmed yesterday, as has a primary-school aged child from north Ealing, London.
A six-year-old died in Ashford, Surrey in late November.
The UK Health Security Agency (UKHSA) confirmed last week that five children under the age of five have died in England after contracting Strep A in recent weeks, bringing the total number of confirmed deaths of children to eight.
The number could rise today as the UKHSA is expected to release more official data about the outbreak.
Two other English children under 10 also died within seven days of being diagnosed, although the dates of their deaths are currently unknown.
Meanwhile, it has been reported that there have been eight cases of severe strep disease in Scotland, but no deaths. It is not known whether there are any ongoing severe cases in Wales and Northern Ireland.
