Flemming Konradsen

The global distribution of fatal pesticide self-poisoning: Systematic review

BackgroundEvidence is accumulating that pesticide self-poisoning is one of the most commonly used methods of suicide worldwide, but the magnitude of the problem and the global distribution of these deaths is unknown.MethodsWe have systematically reviewed the worldwide literature to estimate the number of pesticide suicides in each of the World Health Organisations six regions and the global burden of fatal self-poisoning with pesticides. We used the following data sources: Medline, EMBASE and psycINFO (1990–2007), papers cited in publications retrieved, the worldwide web (using Google) and our personal collections of papers and books. Our aim was to identify papers enabling us to estimate the proportion of a countrys suicides due to pesticide self-poisoning.ResultsWe conservatively estimate that there are 258,234 (plausible range 233,997 to 325,907) deaths from pesticide self-poisoning worldwide each year, accounting for 30% (range 27% to 37%) of suicides globally. Official data from India probably underestimate the incidence of suicides; applying evidence-based corrections to Indias official data, our estimate for world suicides using pesticides increases to 371,594 (range 347,357 to 439,267). The proportion of all suicides using pesticides varies from 4% in the European Region to over 50% in the Western Pacific Region but this proportion is not concordant with the volume of pesticides sold in each region; it is the pattern of pesticide use and the toxicity of the products, not the quantity used, that influences the likelihood they will be used in acts of fatal self-harm.ConclusionPesticide self-poisoning accounts for about one-third of the worlds suicides. Epidemiological and toxicological data suggest that many of these deaths might be prevented if (a) the use of pesticides most toxic to humans was restricted, (b) pesticides could be safely stored in rural communities, and (c) the accessibility and quality of care for poisoning could be improved.

Pesticide poisoning in the developing world—a minimum pesticides list

In parts of the developing world, pesticide poisoning causes more deaths than infectious diseases. Use of pesticides is poorly regulated and often dangerous; their easy availability also makes them a popular method of self-harm. In 1985, the UN Food and Agriculture Organisation (FAO) produced a voluntary code of conduct for the pesticide industry in an attempt to limit the harmful effects of pesticides. Unfortunately, a lack of adequate government resources in the developing world makes this code ineffective, and thousands of deaths continue today. WHO has recommended that access to highly toxic pesticides be restricted--where this has been done, suicide rates have fallen. Since an Essential Drugs List was established in 1977, use of a few essential drugs has rationalised drug use in many regions. An analogous Minimum Pesticides List would identify a restricted number of less dangerous pesticides to do specific tasks within an integrated pest management system. Use of safer pesticides should result in fewer deaths, just as the change from barbiturates to benzodiazepines has reduced the number of deaths from pharmaceutical self-poisoning.

Reducing acute poisoning in developing countries—options for restricting the availability of pesticides

Hundreds of thousands of people are dying around the world each year from the effects of the use, or misuse, of pesticides. This paper reviews the different options to reduce availability of the most hazardous chemicals, focusing on issues in developing countries. Emphasis is placed on the fatal poisoning cases and hence the focus on self-harm cases. Overall, it is argued here that restricting access to the most hazardous pesticides would be of paramount importance to reduce the number of severe acute poisoning cases and case-fatalities and would provide greater opportunities for preventive programmes to act effectively. The aim should be to achieve an almost immediate phasing out of the WHO Classes I and II pesticides through national policies and enforcement. These short-term aims will have to be supported by medium- and long-term objectives focusing on the substitution of pesticides with safe and cost-effective alternatives, possibly guided by the establishment of a Minimum Pesticide List, and the development of future agricultural practices where pesticide usage is reduced to an absolute minimum. Underlying factors that make individuals at risk for self-harm include domestic problems, alcohol or drug addiction, emotional distress, depression, physical illness, social isolation or financial hardship. These should be addressed through preventive health programmes and community development efforts.

Pesticide poisoning: A major health problem in Sri Lanka

Acute pesticide poisoning is a major public health problem in Sri Lanka. In several agricultural districts, it precedes all other causes of death in government hospitals. Most of the acute poisoning cases are intentional (suicide) and occur among young adults, mainly males. Poisoning due to occupational exposure is also common, but less well documented. In an irrigation area in Sri Lanka a very high incidence of serious pesticide poisoning was observed, with 68% due to intentional ingestion of liquid pesticides. It is argued that the easy availability and widespread use of highly hazardous pesticides is the most important reason for this high number of poisoning cases. The frequent application of highly hazardous pesticides in high concentrations was often irrational and posed serious health and financial risks to the farmers. Sales promotion activities and credit facilities promoted this excessive pesticide use, which was not counteracted by an agricultural extension service. Hazardous practices when spraying pesticides were due to the impossibility of applying recommended protective measures under the local conditions, rather than to lack of knowledge. Current emphasis on programs that promote the safe use of pesticides through education and training of farmers will be ineffective in Sri Lanka because knowledge is already high and most poisoning cases are intentional. Instead, enforcement of legislation to restrict availability of the most hazardous pesticides would result in an immediate health benefit. Improved agricultural extension services to promote alternative non-chemical methods of pest control is the most important strategy, in the long term, to prevent acute pesticide poisoning.

Malaria and urbanization in sub-Saharan Africa

There are already 40 cities in Africa with over 1 million inhabitants and the United Nations Environmental Programme estimates that by 2025 over 800 million people will live in urban areas. Recognizing that malaria control can improve the health of the vulnerable and remove a major obstacle to their economic development, the Malaria Knowledge Programme of the Liverpool School of Tropical Medicine and the Systemwide Initiative on Malaria and Agriculture convened a multi-sectoral technical consultation on urban malaria in Pretoria, South Africa from 2nd to 4th December, 2004. The aim of the meeting was to identify strategies for the assessment and control of urban malaria. This commentary reflects the discussions held during the meeting and aims to inform researchers and policy makers of the potential for containing and reversing the emerging problem of urban malaria.

Water management for controlling the breeding of Anopheles mosquitoes in rice irrigation schemes in Kenya

An experiment to assess the impact of intermittent irrigation on Anopheles larval populations, rice yields and water use was conducted in the Mwea rice irrigation scheme in Kenya. Four water regimes including intermittent irrigation were tested in a complete randomized block experimental design. Intermittent irrigation was carried out on a weekly schedule, with flooded conditions from Saturday through Tuesday morning. Larval sampling at each plot was conducted every Monday and prior to draining of intermittently irrigated subplots on Tuesday. All the adult anopheline mosquitoes emerging from larvae collected in the experimental plots were identified as being An. arabiensis. By far the highest numbers of An. arabiensis 1st instar larvae were found in the intermittently irrigated subplots, indicating that the water regime provided the most attractive environment for egg laying. However, the ratio between the 4th and 1st instar larvae in the subplots was only 0.08, indicating very low survival rates. In contrast, the 4th/1st instar ratio for subplots with other water management regimes ranged between 0.27 and 0.68, suggesting a correspondingly higher survival than observed with intermittent irrigation. The total number of 4th instars was almost the same in the intermittently irrigated subplots and the irrigation system normally practised by the farmers. The failure to eliminate larval development up to the 4th instar in the former method was attributed to residual pools of water. Larval abundance fluctuated throughout the 12-week sampling period. The highest larval densities were recorded in the 3 weeks after transplanting the rice seedlings. Afterwards, larval numbers dropped dramatically as the height of rice plants increased. Rice yields at harvest did not show statistically significant differences among subplots with different water regimes. The average yield per hectare ranged from 4.8-5.3 metric tonnes. The average daily water percolation/seepage rate was 3.6 mm and did not significantly differ among different water management regimes. Further research is necessary to, among other things, determine whether rice yields could be increased by having flooded and drained intervals that were different from those used in this study. It would likewise be important to assess on a wider scale the feasibility of implementing intermittent irrigation with respect to farmer acceptance and required changes in irrigation system design and management.

Keeping Up Appearances: Perceptions of Street Food Safety in Urban Kumasi, Ghana

The growing street food sector in low-income countries offers easy access to inexpensive food as well as new job opportunities for urban residents. While this development is positive in many ways, it also presents new public health challenges for the urban population. Safe food hygiene is difficult to practice at street level, and outbreaks of diarrheal diseases have been linked to street food. This study investigates local perceptions of food safety among street food vendors and their consumers in Kumasi, Ghana in order to identify the most important aspects to be included in future public health interventions concerning street food safety. This qualitative study includes data from a triangulation of various qualitative methods. Observations at several markets and street food vending sites in Kumasi were performed. Fourteen street food vendors were chosen for in-depth studies, and extensive participant observations and several interviews were carried out with case vendors. In addition, street interviews and Focus Group Discussions were carried out with street food customers. The study found that although vendors and consumers demonstrated basic knowledge of food safety, the criteria did not emphasize basic hygiene practices such as hand washing, cleaning of utensils, washing of raw vegetables, and quality of ingredients. Instead, four main food selection criteria could be identified and were related to (1) aesthetic appearance of food and food stand, (2) appearance of the food vendor, (3) interpersonal trust in the vendor, and (4) consumers often chose to prioritize price and accessibility of food—not putting much stress on food safety. Hence, consumers relied on risk avoidance strategies by assessing neatness, appearance, and trustworthiness of vendor. Vendors were also found to emphasize appearance while vending and to ignore core food safety practices while preparing food. These findings are discussed in this paper using social and anthropological theoretical concepts such as ‘purity’, ‘contamination’, ‘hygiene puzzles’, and ‘impression behaviors’ from Douglas, Van Der Geest, and Goffman. The findings indicate that educating vendors in safe food handling is evidently insufficient. Future public health interventions within the street food sector should give emphasis to the importance of appearance and neatness when designing communication strategies. Neglected aspects of food safety, such as good hand hygiene and cleanliness of kitchen facilities, should be emphasized. Local vendor networks can be an effective point of entry for future food hygiene promotion initiatives.

Risk factors for acute pesticide poisoning in Sri Lanka

This report describes the characteristics of patients with acute pesticide poisoning in a rural area of Sri Lanka and, for intentional self‐poisoning cases, explores the relative importance of the different determinants. Data were collected for 239 acute pesticide‐poisoning cases, which were admitted to two rural hospitals in Sri Lanka. Sociodemographic characteristics, negative life events and agricultural practices of the intentional self‐poisoning cases were compared with a control group. Most cases occurred among young adults and the large majority (84%) was because of intentional self‐poisoning. Case fatality was 18% with extremely high case fatality for poisoning with the insecticide endosulfan and the herbicide paraquat. Cases were generally younger than controls, of lower educational status and were more often unemployed. No agricultural risk factors were found but a family history of pesticide poisoning and having ended an emotional relationship in the past year was clearly associated with intentional self‐poisoning. The presence of mental disorders could only be assessed for a subsample of the cases and controls and this showed that alcohol dependence was a risk factor. This study shows that acute pesticide poisoning in Sri Lanka is determined by a combination of sociodemographic and psychological factors. Suggestions are given for interventions that could control the morbidity and mortality due to acute pesticide poisoning in developing countries.

STRONG ASSOCIATION BETWEEN HOUSE CHARACTERISTICS AND MALARIA VECTORS IN SRI LANKA

The objective of this study was to determine whether house characteristics could be used to further refine the residual insecticide-spraying program in Sri Lanka. Indoor-resting mosquito densities were estimated in 473 houses based on fortnightly collections over a two-and-a-half-year period. The type of house construction and the exact location of all houses were determined. In a multivariate analysis, distance of less than 750 meters between a house and the main vector-breeding site was strongly associated with the presence of Anopheles culicifacies in the house (odds ratio [OR] 4.8, 95% confidence interval [CI] 3.4-6.8) and to a lesser extent with the presence of An. subpictus (OR 1.4, 95% CI 1.1-1.7). Poor housing construction also was an independent risk factor (OR for An. culicifacies 1.3, 95% CI 1.0-1.9; OR for An. subpictus 1.3, 95% CI 1.0-1.6). It is recommended that a malaria control strategy focus on residential areas within 750 meters of streams and rivers, with special attention given to areas with the poorest type of house construction.

Geographic Structure of Plasmodium vivax: Microsatellite Analysis of Parasite Populations from Sri Lanka, Myanmar, and Ethiopia

Genetic diversity and population structure of Plasmodium vivax parasites can predict the origin and spread of novel variants within a population enabling population specific malaria control measures. We analyzed the genetic diversity and population structure of 425 P. vivax isolates from Sri Lanka, Myanmar, and Ethiopia using 12 trinucleotide and tetranucleotide microsatellite markers. All three parasite populations were highly polymorphic with 3-44 alleles per locus. Approximately 65% were multiple-clone infections. Mean genetic diversity (H(E)) was 0.7517 in Ethiopia, 0.8450 in Myanmar, and 0.8610 in Sri Lanka. Significant linkage disequilibrium was maintained. Population structure showed two clusters (Asian and African) according to geography and ancestry. Strong clustering of outbreak isolates from Sri Lanka and Ethiopia was observed. Predictive power of ancestry using two-thirds of the isolates as a model identified 78.2% of isolates accurately as being African or Asian. Microsatellite analysis is a useful tool for mapping short-term outbreaks of malaria and for predicting ancestry.