Monday, 14 May 2012

1 million OP poisonings worldwide, every year

Pesticides, plant poisonings and snake envenomation:
South Asia's 'toxic' challenges

By Anna Joseph.
Anna is the Communications Officer at the Centre. 

When I asked herpetologist Gerry Martin (of National Geographic fame) at lunch, Saturday before last, for advice on protecting my dogs against a snake bite – they had already killed two cobras in our backyard – little did I know that tragedy would strike before the end of the day. 

Though Sparky and Lucky, the female, managed to bring down the intruder in their territory, yet another cobra, Lucky’s luck 
had run out.  The tell-tale signs were noticed too late and she died a horrific death.

Gerry Martin was in town to speak at the workshop on pesticides, plant poisonings and snake envenomations, jointly organized by us, the team at the South Asian Cochrane Centre, and the Toxicology Special Interest Group, both based at the Christian Medical College, Vellore. 

That Lucky died on the day of this workshop was a real twist of fate.

Was the workshop relevant? 

Suicides with pesticides, specifically organophosphates (esters of phosphoric acid), and plant poisons, and deaths occurring due to snake bites are grave public health problems that plague South Asia. The lack of effective methods of treatment and large-scale mortality are the two reasons behind this. This clearly points out that the need of the hour is better understanding of these public health calamities and to find ways to combat them; this is what the workshop hoped to initiate.

What was the specific aim of the workshop?

The aim of the two-day workshop titled:

“Formulating a research agenda for treatment: A workshop on pesticide and plant poisonings and snake envenomations” 
was, as per the official communication:

“to develop a focused research agenda for the South Asian region to provide guidance to policy makers, funders and scientists” by  

a) “catalyse(ing) interactions between known experts” and  b) “examine(ing) the key questions of therapy in the area of pesticide and plant poisoning and snake envenomation”.

Before examining whether or not this goal was achieved, let’s take a look at the statistics.

Some facts and figures


The Asia-Pacific region has been referred to as “the suicide belt of the world”. Of the various options available for suicide, the ingestion of pesticides is the most popular one here, primarily on account of their ease of availability. And unlike in industrialised nations, the high levels of toxicity translate to high rates of mortality even if the step taken was a call for help or attention. In many countries in South-East Asia, the death rates for deliberate self-poisoning can be 40 per cent. 

Worldwide, there are around 1 million OP poisonings per year with several hundred thousand resulting in fatalities. 

Though Sri Lanka no more has the highest suicide rates in the world, it is waging an ongoing battle against self-poisoning using pesticides. The Sri Lankan government has been able to bring down the numbers by banning (Paraquat, for example) and reducing the toxicity levels of some of these agents; for eg: some of the OP pesticides. (1)

What happens to the body with the intake of organophosphates? 

Organophosphates, the most common of the organophosphorus compounds, are the basis of many insecticides, herbicides, and nerve gases.

When organophosphosphorus enters the body, it plays havoc with the maintenance functions of the body, throwing some functions into overdrive, a bit like pressing the accelerator and being unable to take your leg off ... and some into shut down. As a result, there is involuntary urination, defecation, shedding of tears, vomiting etc. 

The onset and severity of the symptoms depends upon the chemical, the route of exposure and the quantity consumed. If not treated, the symptoms herald certain death.

Plant poisonings:

Unlike in most other parts of the world, the ingestion of parts of poisonous plants is a common cause of death in South Asian countries like India and Sri Lanka. The two most commonly ingested plants are Yellow oleander (Thevetia Peruviana) or “Manjai Alari” in Tamil and Cleistanthus collinus or “Oduvan” in Tamil. 

Yellow oleander, a small ornamental shrub, has highly toxic seeds that when ingested causes symptoms like vomiting, diarrhoea, abnormally high levels of potassium in the blood, and  malfunctioning or total shut down of the heart. Cleistanthus collinus causes, mainly, the potassium levels to rise abnormally as well as cardiac malfunctioning or arrest. (2)

At present, there are no reliable statistics about this type of poisoning.

Snake envenomations:

The four snakes, mainly responsible for envenomations  in South Asia are Cobra, Krait, Saw-scaled viper and Russel’s viper. Their venom induces, respectively, neurotoxicity (toxicity to the nerves and nerve cells) haemotoxicity (haemotoxins  are toxins that destroy red blood cells, disrupt the process of blood clotting, and /or cause organ degeneration and tissue damage), combinations of the two and haemtoxicity with renal failure.

According to the estimates of a 2008 systematic review in PLoS Medicine (an international, peer-reviewed, open-access healthcare journal), the highest burden of snakebite envenomations and death occurs in South and Southeast Asia and in sub-Saharan Africa. According to the review, India had the highest annual number of envenomations (81,000) and deaths (nearly 11,000) in the world

Worldwide, at least 421,000 envenomations and 20,000 deaths from snakebite occur every year; the actual numbers, the researchers suggest, could be as high as 1.8 million envenomations and 94,000 deaths. (3, 4, 5)

The sessions 

The short list given below, which includes some of the key topics of discussion, will give  you a glimpse into the workshop proceedings.  

For pesticides
· “Emerging issues of pesticide regulation in India” by Sarita Balla, Joint Director (Med), Medical Toxicology Division, Ministry of Agriculture 
· “The experience of banning of endosulphan in Kerala” by Jayakumar C, of Thanal, a public interest research and advocacy organisation

Plant poisoning
· “Short experiences regarding plant poisoning from Bangladesh” by Mohammed A Faiz, Retired Professor of Medicine, Dhaka 
· “Yellow oleander poisoning in Sri Lanka” by Dr. Ariaranee Ariaratnam, Department of Clinical Medicine, Faculty of Medicine, University of Colombo

Snake envenomation
· “Clinical spectrum of snake bite in India and review of treatment studies” by H S Bawaskar, Bawaskar Hospital and Research Centre, Mahad 
· “Mechanisms of snake venom toxicity” by R Manjunatha Kini, Department of Biological Science, National University of Singapore 

What was accomplished by the workshop? 

Though significant research has been done and path-breaking initiatives undertaken to address these issues, there are too many unanswered questions as well as many questions that need to be asked in the ‘discipline’ of toxicology. That toxicology is still not a formal discipline is telling in itself. 

This workshop brought together scientists, activists, medical professionals, representatives of the farming community, the industry and the emergency services, as well as many other stakeholders from various parts of India and South Asia. It provided a setting and a forum where these stakeholders could brainstorm, listen to and be heard, while grappling with these unasked and unanswered questions.

For the small army of dedicated individuals and institutions relentlessly fighting to save precious lives across South Asia and the rest of the world, it was a both a pit-stop and a shot in the arm.

(Note: The recommendations drafted at the workshop are in the process of being ratified by all the partners for finalization.) 

First follow-up workshop
Dates: 11 & 12 Mar, 2013
Venue: Christian Medical College, Vellore, Tamil Nadu  


“The more I learned about the use of pesticides, the more appalled I became. I realized that there was material for a book. What I discovered was that everything which meant the most to me as a naturalist was being threatened, and that nothing I could do, would be more important.”

-       Rachel Carson, who triggered the modern environmental movement, when talking of the motivation to write her revolutionary book, Silent Spring. 

1. Drinking problem: Combating pesticide poisoning in South Asia [Internet]. [cited 2012 May 14]. Available from:
2. Eddleston, M, C A Ariaratnam, L Sjöström, S Jayalath, K Rajakanthan, S Rajapakse, D Colbert, et al.    “Acute Yellow oleander (Thevetia Peruviana) Poisoning: Cardiac Arrhythmias, Electrolyte Disturbances, and Serum Cardiac Glycoside Concentrations on Presentation to Hospital.” Heart (British Cardiac Society) 83, no. 3 (March 2000): 301–306.
3. WHO, South East Asia. Guidelines for the Clinical Management of Snakebites in South-East Asian region.2005.
4. Warrell DA. Snake bite: A neglected problem in twenty-first century India. The National Medical Journal of India.2011;24 (6): 321-27.
5. Kasturiratne A, Wickremasinghe AR, de Silva N global burden of snakebite: a literature analysis and modelling based on regional estimates ofenvenoming and deaths. PLoS Med. 2008  4;5(11): 1591-1604