Paraquat Poisoning in Japan: A Hospital-based Survey

Background: Paraquat has been a matter of grave concern around the world, including Japan, in light of high mortality rates and numerous fatalities. Method: We undertook a cross-sectional survey of pesticide poisoning by collecting data for 6 years, from 1998 to 2003, from 102 hospitals affiliated with the Japanese Association of Rural Medicine. From these cases, we analyzed those with exposure to paraquat. Results: There were 79 paraquat poisoning cases, including 71 cases of suicide. Of the suicide cases with 5% paraquat and 7% diquat products, more than 80% resulted in suicide deaths. All people who used 24% paraquat products completed suicide. The outcomes of these cases were related to age and volume of ingestion. The prognosis line proposed by Proudfoot in 1979 continues to explain the final outcome of almost all cases even though more than 25 years have passed since it was first proposed. More than 80% of fatalities died within the first three days of ingestion. Conclusion: Numerous lifesaving methods have been proposed by physicians around the world. However, almost all of these methods treat pulmonary disorders in the sub-acute and subsequent periods and seem unable to effectively decrease mortality rates. It is necessary to take administrative measures to reduce paraquat concentrations in products and, furthermore, to impose strict restrictions on its distribution.