Could cyanobacteria harm humans?
If you hadn't heard of it - don't worry - neither had we until recently.
It is a toxic algae - which is swirling in our rivers and lakes and it's one of the most lethal toxins out there in our natural environment. The algae has been particularly prevalent this summer, in part due to the drought.
Cyanobacteria is killing dogs and the experts are warning - it could kill our children too.
Watch the video for Rebecca Wright’s report.