The Western Health Board is monitoring a probable case of Severe Acute Respiratory Syndrome (SARS) at Mayo General Hospital in Castlebar.
Fifteen deaths internationally have been blamed on the highly-contagious disease which is the subject of an alert from the World Health Organisation.
In Ireland, however, a dispute between the Department of Health and public health doctors could hinder the monitoring of the situation from a public health point of view over the weekend.
The National Disease Surveillance Centre (NDSC) in Dublin said it would normally liaise with public health staff in the region, rather than become directly involved.
The probable case of SARS in Mayo is a middle-aged man who returned from Hong Kong last weekend.
It is understood that the man, who was described yesterday as "not critical", has family in south-east Asia, and stayed on the 11th floor of a hotel there while visiting them earlier this month.
A man who stayed on the ninth floor of the same hotel - the Metropole in the Kowloon Peninsula - has been confirmed as having the condition.
The Mayo man flew back into Stansted Airport on March 16th, and caught a connecting flight to Knock Airport. He looked for medical assistance after feeling unwell and reading reports of the SARS outbreak, and was admitted to Mayo General Hospital on Thursday. He has been kept in isolation and is under the care of a respiratory clinician.
The strain of pneumonia named as SARS has been responsible for up to 15 deaths, and there are over 300 cases reported so far in 11 countries as of the end of this week, according to the World Health Organisation (WHO).
Public health doctors are the only medical staff qualified to deal with situations like SARS in a wider public health context if such a case is confirmed. However, they have been involved in a dispute over lack of an emergency plan for out-of-hours cover since 1994, and voted earlier this week to serve strike notice.
Given the outbreak of the war in Iraq and the identification of SARS, it was agreed to defer serving strike notice for a fortnight, but they are on a work-to-rule, according to the Irish Medical Organisation.
The IMO says public health doctors have given of their time voluntarily in many situations, including the recent anthrax scare and cases of contaminated heroin.
It is understood that the Department of Health expects senior management with public health qualifications to be on hand to monitor the case in Mayo over the weekend.