DDT in the prevention of plague in Ecuador.

There was no satisfactory solution to the plague problem until the advent of DDT, which made it possible to break one of the links in the chain of spread of the disease. DDT has been used in Ecuador since 1946 with great success, particularly in the control of rural plague; it is systematically applied every four months in areas considered to be plague foci. Wherever possible, it is used in the form of 10% dusting-powder, although emulsions and solutions of DDT are also used.Since 1950, however, there have been indications, confirmed by experiments and by information from Brazil, that generations of DDT-resistant fleas are breeding. This creates a serious problem requiring close study if a solution is to be found and if one of the most effective weapons for plague-control is not to be rendered useless.