The Health Service Executive is investigating the deaths of six people at a private nursing home in Buncrana, Co Donegal which took place in the last eleven days.
Five of the deaths occurred in a cluster in the last five days and it has been reported that these may have been the result of a respiratory-type illness.
All of the people who died were aged over eighty.
Of the remaining 39 residents at the nursing home, 27 are reported to be showing respiratory symptoms and are being treated with anti-viral drugs.
Their condition is not said to be critical, but visitor restrictions are in place.
“It has been reported that these deaths may have been as a result of a respiratory type illness,” said a HSE spokesman.
“The HSE is fully investigating the matter and all appropriate treatment and control measures have been put in place,” the spokesman added. “All residents in the nursing home are currently receiving either active or preventative treatment.”
Dr Peter Wright, director of public health at the HSE North West, said they were “closely managing and monitoring” the situation.
“Respiratory illness is a common cause of death in older people,” he said.
“The public health team will work closely with the nursing home management to determine the nature of the illness.
“Samples have been sent to the National Viral Reference Laboratory for determination.”
Health Minister James Reilly and Older People’s Minister Kathleen Lynch issued a statement saying they had learned with regret of the deaths and are being kept fully informed.
In addition to the HSE actions Mr Reilly said he has talked with the Health Information and Quality Authority (HIQA) about the matter.
“On foot of that conversation, Hiqa will now visit the home tonight and tomorrow to ensure that all action is taken in the best interests of the care and welfare of the residents and staff,” a spokesman for the minister said.
The ministers both expressed their condolences to the families of the dead residents.