Privatization of mosquito control services in urban areas.

Abstract

Clarke Environmental Mosquito Management, Inc. is the largest privately-owned mosquito control company in the United States. Since 1946, Clarke has provided professional contract mosquito control services which are developed using a community-based, integrated mosquito management philosophy stressing environmental sensitivity and economic feasibility. The company is presently monitoring and controlling mosquitoes for over 250 communities, including most of Metropolitan Chicage, Illinois. In addition, Clarke provides complete programs for a number of small mosquito abatement districts ranging in size from 18-25 square miles. In general, the community programs are funded through municipal taxes and approved by the city councils. The mosquito abatement districts have a Board of Trustees which levies taxes and is responsible for overseeing the contract services. The advantages of private contracting in a community-based program include the ability to individualize a program to meet the local needs of the community and to provide quick response to problem areas. Private contractors are subject to annual reviews. Community leaders can assist in the course of action, making adjustments in the pro- grain strategy easier to implement. In addition, privatization can often result in considerable financial savings. For example, in northeastern Illinois the average cost of a fully staffed mosquito abatement district is $2.15 per citizen or $6,622.00 per square mile. In nearby DuPage County, a 338 square mile county which is covered primarity by a community-based private contractor, the cost is approximately $1.34 per citizen or $3,366.00 per square mile. In the State of Illinois, there are 55 mosquito species, two of which are of primary concern. The primary nuisance species is Aedes vexans. Although Ae. vexans presents no major public health hazard, broods of these vicious biting mosquitoes can migrate up to 20 miles and cause from 70 to 90% of the season's annoyance. The other species, Culex pipiens, the northern house mosquito, is recognized as the primary vector of St. Louis encephalitis (SLE) virus. Similar in many ways to Aedes aegypti, this mosquito develops in artificial containers, such as clogged roof gutters, tires, tin cans, vases and other water holding containers. The community-based programs developed by Clarke involve 5 components: General Services, Surveillance and Monitoring, Larval Control, Adult Control, and an Encephalitis Contingency Plan. Theoretically, a similar integrated program patterned after the Clarke program could be developed and initiated in collaboration with Health Department officials and community leaders for the control of Ae. aegypti and the prevention of dengue/DHF. For example, Part Ⅰ-General Services includes survey and mapping, public relations programs, a toll-free citizen response system, insurance coverage, monthly reports and quality control services, Part Ⅰ of an Ae. aegypti control program might include: defining the type and distribution of containers producing this species on private property; mapping of breeding areas on public property, providing staff social scientists and health educators to assist comunities in developing a source reduction plan; issuing monthly reports to community leaders and instituting quality control to assure program satisfaction. Part Ⅱ of our program, Surveillance and Monitoring, involves mosquito-borne disease monitoring through the collection of wild bird blood for laboratory testing for antibodies to SLE virus and the monitoring of Cx. pipiens populations in order to provide an early warning of the potential occurrence of human cases of SEE in northeastern Illinois. Similarly, Part II of an Ae. aegypti program could include continuous monitoring of Ae. aegypti populations and possible collection for virus isolation. Part Ⅲ-Larval Control, is the foundation of our program in Illinois and includes computer-based organization and classification of larval development sites. Larval control strategies are based on habitat type and the most appropriate control methodology, for example, stocking of mosquito fish (Gambusia offinis), treatment with B. t. i., methoprene, 5% temefhos (Abate) pellets or 5% Abate Tire Treatment. Part Ⅲ in the hypothetical Ae. aegypti control program would make the private contractor responsible for the development of a community-based program focusing on the individual citizen's role in vector control and the control and/or elimination of breeding areas, such as discarded tires and other large objects, on public property, Part Ⅳ-Adult Mosquito Management includes treatment of harborage areas where large numbers of mosquitoes congregate and spraying of residential areas during periods of excessive annoyance or an encephalitis alert. Adult mosquito control for Ae. aegypti might include house to house treatment of residential areas where dengue cases are detected. Part Ⅴ-The Encephalitis Contingency Plan, provides a contingency program using aerial application of adulticide when an SLE alert has been issued. Part Ⅴ of a Dengue Contingency Plan would outline a sequence of events the contractor would follow in the event of an encephalitis alert, this might include intensified mosquito surveillance, concentrated, community-wide information systems and area-wide adult mosquito control. The program under private contract would be evaluated annually and adjustments in the strategy would be implemented to ensure continuous improvement.