Death by insecticideBMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f2029 (Published 28 March 2013) Cite this as: BMJ 2013;346:f2029
- Subhankar Chatterjee, sixth semester MBBS Student, RG Kar Medical College and Hospital, Kolkata, India,
- Haris Riaz, researcher, Dow University of Health Sciences, Karachi, Pakistan
- Correspondence to: H Riaz
The Times of India recently reported the suicide of a 72 year old security guard with chronic illness and depression who had ingested an organophosphate insecticide at home.1 In another incident, a 45 year old cotton farmer with money worries ingested insecticide and died.2
Such media reports represent only a fraction of actual cases.3 Worldwide, an estimated 750 000-3 000 000 people are deliberately or unintentionally poisoned by organophosphate chemicals a year, with an estimated 300 000 deaths.4 And in India the annual number of cases of organophosphate poisoning might be as high as 76 000.5 Organophosphates are implicated in an estimated half of all admissions for poisoning to Indian emergency departments.6
“It is a major public health problem”
Reports of organophosphate poisoning are increasing in the medical literature.7 “It is a major public health problem as it [organophosphate pesticide] is the most common agent used all over India as a suicidal poison,” T K Bose, head of forensic medicine and toxicology, College of Medicine and J N M Hospital, West Bengal University Of Health Sciences, told the BMJ. “Users should be well informed about the dangers of these potentially toxic pesticides,” he said, calling for researchers to develop antidotes and invent new less toxic pesticides.
Organophosphate chemicals such as malathion and parathion are used as agricultural pesticides. Some, such as tribufos, are used as herbicides. They inhibit acetylcholine esterase through phosphorylation and can enter the body easily through inhalation, ingestion, and contact with skin. Symptoms of poisoning can include diarrhoea, hypertension, seizures, and depression. Chronic exposure in fetuses and young children can hamper neurogenesis.8 9
Unintentional poisoning accounts for many fewer deaths than intentional poisoning.10 A prospective study in a government hospital emergency department found suicidal motives in most cases, with mostly farmers and married women poisoned.11 All ages are susceptible to organophosphate poisoning, and children are often poisoned unintentionally.12 Healthcare workers who manage patients with organophosphate poisoning are also vulnerable to pesticide related illness.13
Use of organophosphates in agriculture and fumigation programmes
In India 70% of the workforce are engaged in agriculture, with widespread unregulated use of these pesticides. “There is a hypothesis that this poisoning has increased in recent times primarily due to the pressures in India’s agrarian economy. Poor farmers take loans to buy pesticides to get a good harvest. However, when the harvest doesn’t do well and they are faced with the prospect of bankruptcy, they end their lives by consuming the very same pesticides that they used in their fields,” Rakesh Biswas, professor of internal medicine at the People’s College of Medical Sciences, Bhopal, told the BMJ. Organophosphates for use indoors and in fumigation programmes to control dengue and malaria, for example, may also give rise to cases of poisoning.14
Case fatality rate remains high, at 15-30%,15 because of a lack of antidotes and poor intensive care management.16 Treatment for acute poisoning is essentially supportive, with atropine, oximes, and diazepam.17 Atropine is the mainstay of treatment but there are no clear guidelines on dose and duration. Early resuscitation with atropine, oxygen, respiratory support, and fluids improves oxygen delivery to tissues. A 2009 double blind randomised placebo controlled trial showed that pralidoxime, commonly given in acute poisoning, does not improve survival.18 New agents such as magnesium sulphate are in use, but clinical efficacy has not been shown.19 It is not known if artificial ventilation improves mortality rates, Biswas said.
Dibakar Haldar, associate professor at the department of community medicine of R G Kar Medical College, Kolkata, pointed out that published studies of organophosphate poisoning in India tend to be hospital based, including patients of diverse geographical origin and social status, making them hard to generalise to preventive and treatment guidelines. “Community based studies to estimate the incidence and determinants of this issue are needed,” he told the BMJ. “Prospective family based studies could be done in primary healthcare centres.”
Regulation of organophosphates
Legislation has reduced organophosphate poisoning in the developed world, but lawmakers are yet to tackle the problem in developing countries. For instance, the United States Environmental Protection Agency’s ban on public use of organophosphates resulted in a progressive decline in reports of poisoning in the following two decades.20
Studies have shown a drop in reported cases of poisoning after restrictions on the domestic use of some organophosphate pesticides.21 Some European experts have controversially called for a ban on indoor use of organophosphate pesticides.22
“There is a need for legislation in all Asian countries including India.” said Mahdi Balali-Mood, visiting professor at Newcastle University, UK, and professor of medicine and clinical toxicology, Mashhad University of Medical Sciences, calling also for control on importation and safe use of organophosphate pesticides. “There is considerable evidence that increasing public awareness reduces toxic exposure,” he said.23
Haldar suggested that sales of pesticides might be regulated as for prescribed drugs. It should be “compulsory to have a written recommendation by the panchayat raj [local assembly] for purchasing any organophosphate,” he told the BMJ. Bose said that more vigilance was needed “on storage, marketing and sale” as well as “education as how to use it safely and keep it unreachable to children or people prone to suicides.”
And Biswas called for an educational revolution: “Indian farmers need to be trained in organic farming.”
Cite this as: BMJ 2013;346:f2029
Competing interests: We have read and understood the BMJ Group policy on declaration of interests and have no relevant interests to declare.
Provenance and peer review: Commissioned; not externally peer reviewed.