For example, the health sector expenditure of developing countries for the control and prevention of communicable diseases, particularly tropical and vector-borne diseases, is estimated at US$ 2,000 million annually. International financial support might be expected to contribute about one third of the health sector costs, or US$ 600 million, annually. This includes US$ 4 million annually for the support of international institutions. In addition, vector control services and insecticides require annual expenditures of the order of US$ 1,000 million annually.