The phrase "sporadic outbreaks" means that incidents or occurrences of something, such as a disease or a problem, happen randomly or irregularly, rather than consistently or constantly. Full definition
So far, we know very little about the media in the numerous new democracies around the world except sporadic outbreaks of anger from NGOs specialised in media freedom. (blog.politics.ox.ac.uk)
Slowly, this disease is re-emerging in sporadic outbreaks in animal shelters, and researchers are on the hunt to discover why. (morrisanimalfoundation.org)
For the time it remained, so far as we know, without organization or leadership, but sporadic outbreaks proved that its force was far from spent. (religion-online.org)