The most effective step would obviously be the extermination of the Anopheles mosquito.
In the century leading up to its extermination, smallpox killed about 500,000,000 people.
Palpalis, although in South Africa there can be no question that the extermination of big game has been followed or accompanied by the disappearance of tsetse from many localities in which they formerly abounded.
Has been brought about rather by extermination than specialization, and their distinctive facies by the development and multiplication of the surviving types.
Pigs and a hardy breed of ponies find a good living in the forest; and in spite of an act in 1851 providing for their extermination or removal, a few red deer still survive.