Vector-borne infections in the tropics and health policy issues in the twenty-first century.

Over the past 2 decades scientific advances and evolving strategies have significantly contributed to improved tools for control of vector-borne infections. These are: diagnostics--rapid assessment methods, non-invasive or minimally so yet sensitive and specific; new chemotherapeutics; pyrethroid insecticides and biological insecticidal products; refined strategies, such as combination therapy, rotation of insecticides for resistance management, community-directed treatment, standardized monitoring and evaluation to define programme progress; better epidemiological knowledge through improved identification of parasites and vectors; GIS, remote sensing and climate models which provide tools for epidemic prediction, planning control programmes and permit effective policy analysis; greater involvement of NGDOs (non-governmental development organizations) and CSOs (civil society organizations) in control; advent of donation programmes which involve community-based or directed mass drug distribution. Future problems could be: (1) the over-emphasis on inflexible financing by the insistence of donors on SWAps (sector-wide investment), (2) the over-reliance on pyrethroid pesticides, (3) the over-expectation that basic research will provide new drugs and vaccines for resource-poor settings in the necessary time scales, and (4) the failure to recognize that biological processes have an inherent capacity for change which outstrips the capacity of health services to respond. Malaria is a paradigm of an 'emerging disease'. (5) The challenge of implementing a 'vertical' approach to disease control within national health programmes, in the face of significant donor opposition to such programmes is a challenge even when such approaches will secure a 'public good'.