countries of the Americas presented a consistent pattern of low rates of malaria until the late 1970s, followed by a geometric increase in malaria incidence in subsequent years. According to Roberts et al. (2000), true growth in malaria incidence corresponds temporally to changes in global strategies for malaria control. Underlying the concordance of these events is a causal link between decreased spraying of dwellings with DDT and increased malaria. Separate analyses of data from 1993 to 1995 showed that countries that have recently discontinued their spraying programs are reporting major increases in malaria incidence. The history of the struggle against malaria in Brazil is over 50 years old, and the most frequently used strategy has been spraying of domiciles with DDT (Souza, 1998). Although DDT brought undeniable benefits to public vector control campaigns, its use was banned due to its eco-toxicological risks as a consequence of its persistence in the environment, bioaccumulation in food chains, and slow elimination from living beings. Workers involved with domiciliary DDT spraying as part of vector control campaigns are particularly vulnerable to contamination by this substance due to their high exposure. Souza (1998) conducted a survey on the use of insecticides by FUNASA/MT sprayers and called attention to their lack of training and preparation for handling such compounds. The author also reported that even when personal protective equipment was available, workers resisted using it, claiming that it was uncomfortable and interfered with their work. The same situation is common among agricultural workers in developing countries, where pesticides tend to be handled carelessly, and personal protective equipment is seldom used (Jeyaratnam, 1993). Organochlorine pesticide residues have been detected in the blood serum of exposed and unexposed workers around the world. Several studies on the contamination of personnel working in vector control household spraying have been conducted in Brazil. In the State of Minas Gerais, Franklin & Peixoto (1986) studied 106 sprayers from SUCAM (the Superintendency of Public Health Campaigns) who handled HCH (hexachlorocyclohexane, 30% gamma-isomer), widely utilized to control Chagas disease vectors, to determine the serum levels of this insecticide. A control group of unexposed individuals was also analyzed. Blood samples from 10 unexposed individuals were collected and analyzed. b-HCH was detected in all samples at levels varying from 0.08 to 0.68g/dL, while a-HCH was detected in only three samples. Among the exposed workers, only b-HCH was detected in all samples, at concentrations from 0.19 to 13.44g/dL. This can be explained by the fact that this is the most stable and persistent isomer. No correlation was found between time on the job as sprayers and HCH blood levels. Carvalho & Berbet (1987) measured serum organochlorine insecticides (DDT and HCH) in occupationally exposed vector control workers in the State of Bahia. They reported high absorption levels, exceeding the limits established by occupational health legislation. This excessive absorption occurred partially due to the lack of use of personal protective equipment, workers' habits in the work environment, and lack of knowledge concerning proper handling measures and techniques for pesticide application. Mean serum concentration in a control group was 3.23 2.72g/L for