The National Disease Surveillance Centre has confirmed it is investigating three outbreaks of mumps across Ireland.
The Midlands Health Board said there had been 40 reported cases in the past week among students at the Athlone Institute of Technology.
The outbreak was considered so serious the health board considered shutting down the college last week and canceling graduations.
Free mumps, measles and rubella (MMR) vaccines are being administered to the 4,500 students and staff at the institute to prevent the further spread of the virus.
The NDSC has also received notification of a suspected outbreak in Donegal and another in the Eastern Regional Health Authority area. It is not known how many people are affected.
There were only 32 cases of mumps reported in Ireland in the whole of 2002.
Mumps is a viral infection that causes tenderness and swelling of the parotid gland in the neck. This is also often accompanied by fever and headaches. Mumps often gives the appearance of swollen cheeks or jaw. The symptoms usually last for around ten days.
It is transmitted through droplet spread, in the form of coughing, sneezing and saliva.
It is a potentially serious disease for children and young adults, particularly those in the 15-to-24 age group.
It can cause symptoms similar to meningitis in up to 15 per cent of patients. Young males are at risk of testicular inflammation and even sterility, although this is rare. One in 20 infected women may suffer ovarian inflammation.
The virus can also, in very rare cases, cause encephalitis and deafness, while the fatality rate is around one to three deaths per 10,000 cases.
The recommended protection is the MMR vaccine, which provides around 90 per cent protection. It is feared university age students are susceptible to mumps because they were too old to be vaccinated when the jab was first introduced in 1988. A stronger, two-step vaccine was introduced in 1996.
A number of British universities have begun vaccinating their students against mumps in response to a huge increase in the rate of young people catching the disease. Figures from Britain's Health Protection Agency (HPA) show the number of cases of mumps in England and Wales rose from 180 in 1996 to 1,529 in 2003.
