Malaria control and levels of DDT in serum of two populations in Kwazulu.

Concentrations of p,p'-DDT, p,p'-DDE, and p,p'-DDD were determined in serum of members of households of two different areas of KwaZulu. Annual intradomiciliary application of DDT is used for the interruption of malaria transmission in one area (the exposed group) while the other served as the control. Demographic differences between the two groups resulted in significantly more females in the control group. The two groups were comparable with respect to age. Serum from household members living in DDT-treated dwellings had significantly higher (p less than .005) levels of sigma DDT and metabolites (mean sigma DDT 140.9 micrograms/l) than those from the control area (mean sigma DDT 6.04 micrograms/l). Percentage DDT was also significantly higher (p less than .05) in the exposed group (28.9%) than the control group (8.3%). sigma DDT for the 3-10 yr age interval (168.6 micrograms/l) was significantly higher (p less than .05) than the 20-29 (60.5 micrograms/l) and 30-39 (84.2 micrograms/l) yr age intervals. There seemed to be two groups with regard to accumulation and elimination. The age group 3-29 appeared to be eliminating DDT, most likely accumulated from contaminated breast milk, faster than they accumulated it. From around 29 yr of age accumulation predominated as the levels increased with age. Regression analysis suggested pharmacokinetic differences for DDE and DDT between the two groups. Liver function parameters between the two groups only differed significantly for gamma-glutamyl transferase (gamma GT) (p less than .005), but the influence of difference in alcohol consumption, which was significantly higher in the exposed group (p less than .0001), offered a better explanation. Those of the exposed group that consumed alcohol had a significantly higher (p less than .05) mean gamma GT level (41.5 IU/l) than those that did not (20.2 IU/l), but were not significantly different for sigma DDT (p greater than .05). The safety of DDT used in malaria control for subjects aged 3 and older was confirmed by the levels of DDT in serum when compared with other studies, which showed lack of any negative effects associated with these levels in adults, and an apparently normal liver function in the exposed and control groups.