The HSE has issued a warning against Lyme disease.
The infection is spread by ticks - which are more numerous and more active in the summer months - and people engaged in outdoor pursuits are most at risk.
The HSE says ramblers, campers, mountain bikers, and others who work and walk in forest or grassy areas should be vigilant against tick bites by using insect repellent, wearing long trousers & sleeves and checking for ticks after a day out.
Most people infected with Lyme disease will develop a skin rash, while some people can develop flu-like symptoms. The HSE says "full recovery is generally the rule".
However, Lyme disease can, in a small number of cases, cause severe heart and nervous system disease.
Dr Paul McKeown, HPSC Specialist in Public Health Medicine, said, "Lyme disease has been notifiable in Ireland since 2012 and, since then, there have been between eight and 18 cases notified in Ireland each year.
"However, as many people will not be aware that they are/have been infected or may not seek medical help when unwell, the true incidence of Lyme disease is not accurately known. It is likely that there are at least 50-100 cases in Ireland every year," he added.
