Increase in insecticide space spraying (fogging) activities in Selangor, Malaysia for
management of dengue outbreaks submits vector control operators towards occupational low-level
exposure towards hazardous organophosphate and pyrethroid compounds. Hence, this study was aimed to
determine insecticide poisoning among these workers occupationally exposed to insecticides. Plasma
cholinesterase level was assayed on 106 vector control operators (subject group) and 74 blood donor
samples (control group) to identify insecticide poisoning. Information regarding the workers recent
exposure, type of insecticides used and compliance to personal protective equipment was obtained
through questionnaire. Statistical analysis was then applied to determine differences in cholinesterase
mean level between the subject and control group. Comparison of mean cholinesterase level between the
subjects (7879.70 ±227.94 IU/L) and control group (7067.86 ±1609.71 IU/L) showed significantly higher
(p<0.05) mean cholinesterase level in the subject group. The study indicated absence of inhibition of
cholinesterase level among subject group compared to the control group thus reflects free from
organophosphate poisoning in the vector control operators. Majority of the vector control operators were
Malays. Strict implementation of personal protective equipment use proved to prevent pesticide poisoning
among these workers. These mean cholinesterase levels for both different cohorts is therefore
recommended to be used as reference and need to be updated from time to time. However, it is better if
each individual cholinesterase level is made available as compared to mean population valu
