where fresh water lake or river has created health problem.?

Question

fresh water has solved many health related problems.People say fresh water lakes can give rise to vector born illness.please give evidence if you have.what problems are there in those countries where water is being transported to other regions through open channels.,

Answer 1

I cannot give you the name, but there was a freshwater lake in Africa which was on top of a volcano vent. There was a build-up of lethal gas which finally bubbled to the surface, killing both animals and humans.