Intentional pesticide poisoning and pesticide suicides in Nepal

Intentional pesticide poisoning is a major clinical and public health problem in agricultural communities in low and middle income countries like Nepal. Bans of highly hazardous pesticides (HHP) reduce the number of suicides. We aimed to identify these pesticides by reviewing data from major hospitals across the country and from forensic toxicology laboratories.

We retrospectively reviewed medical records of 10 hospitals for pesticide poisoned patients and two forensic laboratories of Nepal from April 2017 to February 2020. The poison was identified from the history, referral note, and clinical toxidrome in the hospitals and from gas chromatography analysis in the laboratories. Data on demographics, poison, and patient outcome were recorded on a data collection sheet. Simple descriptive analysis was performed.

Among hospital cases (n = 4148), the commonest form of poisoning was self-poisoning (95.8%) while occupation poisoning was rare (0.03%). Case fatality was 5.3% (n = 62). Aluminum phosphide (n = 38/62, 61.3%) was the most commonly identified lethal pesticide for deaths. Forensic toxicology laboratories reported 2535 deaths positive for pesticides, with the compounds most commonly identified being organophosphorus (OP) insecticides (n = 1463/2535; 57.7%), phosphine gas (n = 653/2535; 25.7%; both aluminum [11.8%] and zinc [0.4%] phosphide) and organochlorine insecticides (n = 241/2535; 9.5%). The OP insecticide most commonly identified was dichlorvos (n = 273/450, 60.6%).

The data held in the routine hospital medical records were incomplete but suggested that case fatality in hospitals was relatively low. The pesticides identified as causing most deaths were dichlorvos and aluminum phosphide. Since this study was completed, dichlorvos has been banned and the most toxic formulation of aluminum phosphide removed from sale. Improving the medical record system and working with forensic toxicology laboratories will allow problematic HHPs to be identified and the effects of the bans in reducing deaths monitored.