Stricken — C.K. Kelly Martin

Naomi doesn't expect anything unusual from her annual family trip to visit her grandparents in Ireland. What she finds is a country hit by an unexpected virus that rapidly infects the majority of the Irish population over the age of twenty-one, turning its victims aggravated, blank or violent. Naomi and her friends must survive on their own, without lucid adults, cut off from the rest of the world, until a cure is found.