Comparing the costs and benefits of public policy

As a result of environmental writing in the 1960s and 1970s we decided to end the use of DDT.  In 1962 Rachel Carson wrote a book called the Silent Spring whose science was questionable at best but which quickly became a set of ideas in good currency.  The attached map includes areas where dengue fever has been prevalent in 1970 and now.  Before the elimination of DDT we had reduced the geography of the disease but since the elimination, the infestation (caused by mosquitos) has increased dramatically.     The disease causes high fever (104°) and can disable a person for a week or more.  The disease is rarely fatal but with significant infection can obviously cause reductions in productivity and can be even more dangerous for at risk populations (children, people with chronic diseases, and the elderly).  So was it the right decision?