Hospital-based surveillance for acute pesticide poisoning caused by neurotoxic and other pesticides in Tanzania

Current pesticide suicide surveillance methods used across the African continent: a scoping review protocol

INTRODUCTION

Every year, more than 800 000 people die from suicides of which an estimated 20% are from pesticide ingestion. Multiple studies have estimated that around 77%-80% of these pesticide suicides occur in low/middle-income countries. The full burden of pesticide suicides in African countries remains poorly documented, one reason being the lack of systematic data collection. It is essential to know the number of pesticide suicide cases to guide prevention of further cases occurring. This can be done by informing policy and legislation, and the implementation of targeted bans, as well as raising community awareness around the use of these pesticides, training of healthcare personnel, and influencing the type and level of clinical facility investments into this area of healthcare. The scoping review aims to investigate how pesticide suicide deaths in Africa are recorded by exploring the various surveillance systems in place, as well as highlighting key limitations and data collection barriers.

METHODS AND ANALYSIS

A scoping review will be carried out with the five-stage methodological frameworks set out by Arksey and O'Malley and the Joanna Briggs Institute. Studies in English that looked at pesticide suicide in African countries will be extracted and screened independently by two reviewers against the inclusion and exclusion criteria of this review. Studies' data will be extracted, and a descriptive synthesis developed of their main findings, as guided by the approach of Levac and colleagues.

ETHICS AND DISSEMINATION

Ethics approval is not required for this review as no human participants will be involved. The study findings will be distributed in a peer-reviewed publication.

REGISTRATION DETAILS

This protocol has been submitted for publication to BMJ Open.

The global distribution of acute unintentional pesticide poisoning: estimations based on a systematic review

BACKGROUND

Human poisoning by pesticides has long been seen as a severe public health problem. As early as 1990, a task force of the World Health Organization (WHO) estimated that about one million unintentional pesticide poisonings occur annually, leading to approximately 20,000 deaths. Thirty years on there is no up-to-date picture of global pesticide poisoning despite an increase in global pesticide use. Our aim was to systematically review the prevalence of unintentional, acute pesticide poisoning (UAPP), and to estimate the annual global number of UAPP.

METHODS

We carried out a systematic review of the scientific literature published between 2006 and 2018, supplemented by mortality data from WHO. We extracted data from 157 publications and the WHO cause-of-death database, then performed country-wise synopses, and arrived at annual numbers of national UAPP. World-wide UAPP was estimated based on national figures and population data for regions defined by the Food and Agriculture Organization (FAO).

RESULTS

In total 141 countries were covered, including 58 by the 157 articles and an additional 83 by data from the WHO Mortality Database. Approximately 740,000 annual cases of UAPP were reported by the extracted publications resulting from 7446 fatalities and 733,921 non-fatal cases. On this basis, we estimate that about 385 million cases of UAPP occur annually world-wide including around 11,000 fatalities. Based on a worldwide farming population of approximately 860 million this means that about 44% of farmers are poisoned by pesticides every year. The greatest estimated number of UAPP cases is in southern Asia, followed by south-eastern Asia and east Africa with regards to non-fatal UAPP.

CONCLUSIONS

Our study updates outdated figures on world-wide UAPP. Along with other estimates, robust evidence is presented that acute pesticide poisoning is an ongoing major global public health challenge. There is a need to recognize the high burden of non-fatal UAPP, particularly on farmers and farmworkers, and that the current focus solely on fatalities hampers international efforts in risk assessment and prevention of poisoning. Implementation of the international recommendations to phase out highly hazardous pesticides by the FAO Council could significantly reduce the burden of UAPP.

Acute pesticide poisoning amongst adolescent girls and women in northern Tanzania

BACKGROUND

Acute pesticide poisoning (APP) is reported to affect community health worldwide but its burden in Tanzania is unknown particularly in women. This study examines APP involving adult females and adolescent girls 10 to 19 years in 3 regions of Tanzania which are famous for coffee and vegetable production.

METHODS

Over the period of 12 months, health facility-based surveillance for cases of APP was implemented in 10 Tanzanian healthcare facilities in 2006.

RESULTS

The study identified 108 APP cases of whom 31 (28.7%) occurred amongst adolescent girls. Suicide was the leading poisoning circumstances (60.2%) and the most vulnerable women were 20-29 years old who comprised 38.4% of all cases with suicide as circumstance. Organophosphates (OPs), zinc phosphide, paraquat and endosulfan were common amongst known reported poisoning agents. The annual APP incidence, mortality and Case Fatality Rate for women were 5.1/100,000, 0.2/100,000 and 3.7/100, respectively.

CONCLUSION

APP amongst women in Tanzania is common and this call for diverse preventive interventions to reduce poisoning incidents.

Farmers' pesticide usage practices in the malaria endemic region of North-Western Tanzania: implications to the control of malaria vectors

Background

Pesticides remain the mainstay for the control of agricultural pests and disease vectors. However, their indiscriminate use in agriculture has led to development of resistance to both crop pests and disease vectors. This threatens to undermine the success gained through the implementation of chemical based vector control programs. We investigated the practices of farmers with regard to pesticide usage in the vegetable growing areas and their impact on susceptibility status of An. gambiae s.l.

Methods

A stratified multistage sampling technique using the administrative structure of the Tanzanian districts as sampling frame was used. Wards, villages and then participants with farms where pesticides are applied were purposively recruited at different stages of the process, 100 participants were enrolled in the study. The same villages were used for mosquito larvae sampling from the farms and the surveys were complimented by the entomological study. Larvae were reared in the insectary and the emerging 2–3 days old female adults of Anopheles gambiae s.l were subjected to susceptibility test.

Results

Forty eight pesticides of different formulations were used for control of crop and Livestock pests. Pyrethroids were the mostly used class of pesticides (50%) while organophosphates and carbamates were of secondary importance. Over 80% of all farmers applied pesticides in mixed form. Susceptibility test results confirmed high phenotypic resistance among An. gambiae populations against DDT and the pyrethroids (Permethrin-0.75%, Cyfluthrin-0.15%, Deltametrin-0.05% and Lambdacyhalothrin-0.05%) with mortality rates 54, 61, 76 and 71%, respectively. Molecular analysis showed An. arabiensis as a dominant species (86%) while An. gambiae s.s constituted only 6%. The kdr genes were not detected in all of the specimens that survived insecticide exposures.

Conclusion

The study found out that there is a common use of pyrethroids in farms, Livestocks as well as in public health. The study also reports high phenotypic resistance among An. gambiae s.l against most of the pyrethroids tested. The preponderance of pyrethroids in agriculture is of public health concern because this is the class of insecticides widely used in vector control programs and this calls for combined integrated pest and vector management (IPVM).

Pesticide Health and Safety Challenges Facing Informal Sector Workers: A Case of Small-scale Agricultural Workers in Tanzania

The Tanzania informal sector is growing fast, with precarious working conditions and particular hazards for women and children in agriculture. Hazardous agricultural chemicals including pesticides are mostly imported and have been used for many years. Despite the role played by pesticides in food security and vector control, these chemicals are responsible for acute and chronic illnesses among communities. The availability of obsolete persistent organic pesticides on the open market indicates existence of an inadequate regulatory system. People who get injured or ill in the agriculture sector in Tanzania receive health services in primary health care facilities where professionals have little or no knowledge of pesticides. We are presenting the pesticide health and safety challenges faced by small-scale farmers who fall in the informal sector. Achievements that have been made by the government and other players to reduce and prevent pesticide exposures and poisoning are also outlined.

Acute Pesticide Poisoning in Children: Hospital Review in Selected Hospitals of Tanzania

BACKGROUND

Acute pesticide poisoning (APP) is a serious problem worldwide. Because the burden of childhood APP is unknown in Tanzania, this study describes the distribution, circumstances, and patterns of APP involving children under 18 years in Tanzania.

METHODOLOGY

A 12-month prospective study was conducted in 10 Tanzanian healthcare facilities in 2006 using a data collection tool for surveillance.

RESULTS

Of 53 childhood poisoning cases identified, 56.6% were female. The most common poisoning circumstances were accidents (49.1%) and suicide (30.2%). The most vulnerable children were 16-17 years old (30.2%). Suicide was significantly more common in females (PRR females/males = 1.66; 95% CI = 1.03-2.68) and accidental cases were more common in children aged 10 years or younger. Suicide was concentrated in children over 10 years, comprising 53% of cases in this age group. Organophosphates (OPs), zinc phosphide, and endosulfan were common amongst reported poisoning agents. The annual APP incidence rate was 1.61/100,000.

CONCLUSION

APP is common among children in this region of Tanzania. Prevention of suicide in older children should address mental health issues and control access to toxic pesticides. Prevention of accidents in younger children requires safer storage and hygiene measures. Diverse interventions are needed to reduce pesticide poisoning among children in Tanzania.

Pesticide Exposure and Health Problems Among Female Horticulture Workers in Tanzania

Commercialization of horticulture farming, expansion of farms, and the practice of monoculture favor the proliferation of pests, which in turn increases the need for pesticides. Increased exposure to pesticides is associated with inadequate knowledge on the hazardous nature of pesticides, poor hygiene practices, lack of availability of washing facilities, and insufficient adherence to precautionary instructions on pesticide labels. Mitigating the risks posed by pesticides is considered a less compelling interest than alleviating poverty. Women working in horticulture in Tanzania usually have low levels of education and income and lack decision-making power even on matters relating to their own health. This contributes to pesticide exposure and other health challenges. Because of multiple factors, some of which act as study confounders, few studies on exposure to pesticides and health effects have been conducted among women. This review identified factors that contribute to the increased health effects among women working in the horticultural industry and how these effects relate to pesticide exposure.

Characteristics of Pesticide Poisoning in Rural and Urban Settings in Uganda

Pesticide poisoning is a significant burden on health care systems in many low-income countries. This study evaluates cases of registered pesticide poisonings treated in selected rural (N = 101) and urban (N = 212) health facilities in Uganda from January 2010 to August 2016. In the urban setting, pesticides were the most prevalent single poison responsible for intoxications (N = 212 [28.8%]). Self-harm constituted a significantly higher proportion of the total number of poisonings in urban (63.3%) compared with rural areas (25.6%) where unintentional poisonings prevailed. Men were older than women and represented a majority of around 60% of the cases in both the urban and rural settings. Unintentional cases were almost the only ones seen below the age of 10, whereas self-harm dominated among adolescents and young persons from 10 to 29 years of age. Organophosphorus insecticides accounted for 73.0% of the poisonings. Urban hospitals provided a more intensive treatment and had registered fever complications than rural health care settings. To minimize self-harm with pesticides, a restriction of pesticide availability as shown to be effective in other low-income countries is recommended. Training of health care workers in proper diagnosis and treatment of poisonings and improved equipment in the health care settings should be strengthened.

Pesticide Use and Self-Reported Health Symptoms Among Rice Farmers in Zanzibar

The agrarian population in low- and middle-income countries suffers from a number of adverse health effects due to pesticide exposure. In Zanzibar, the government subsidizes pesticides to enhance local rice production. The objectives of this study were to assess Zanzibar smallholder rice farmers' pesticide use and self-reported health symptoms in relation to pesticide exposure, training, and use of protective measures and to raise awareness for future local policy formulation. An exploratory cross-sectional interviewer-administered study was conducted among 99 rice farmers. Participants were selected based on convenience sampling and stratified by expected exposure category. The study participants reported using pesticides in World Health Organization (WHO) Class II. Of pesticide users, 61% reported one or more symptoms of possible acute pesticide poisoning. Only 50% of pesticide users had received training in safe handling and application of pesticides, but those who had displayed a higher use of protective measures. Farmers who did not use protective measures were more likely to have reported skin irritation and headache, which, together with eye irritation, were the most commonly reported acute symptoms. The main sociodemographic differences between the expected exposure categories of pesticide users and nonusers were in gender and education level. Scaling up of training in safe handling and application of pesticides is needed. Further studies are required to better understand the mechanisms behind the choice to use pesticides or not.

Epidemiology of Organophosphate Poisoning in the Tshwane District of South Africa

BACKGROUND

Organophosphate poisoning is a major public health problem in South Africa. Individuals get exposed to organophosphate in both the domestic and industrial spheres.

METHOD

A cross-sectional study was conducted using retrospective, secondary data of organophosphate poisoning cases over a 3-year period, reported at the Tshwane District surveillance office. Data were analysed using Microsoft Excel, and Epi Info version 7 was used for descriptive statistics.

RESULTS

A total of 207 cases were reported with ages ranging from 10 months to 59 years. Most of the cases were men (58.9%). Intentional poisoning accounted for 51% of cases. Unintentional poisoning accounted for 21.7% of cases, and 26.5% of cases had unknown circumstances of poisoning. A significant number (50.2%) of intentional poisonings were suicide related. Nonsuicidal cases accounted for 47.4% of cases, and deliberate unlawful poisoning accounted for 2.4% of cases. The mortality rate for the whole group was 3.4%.

CONCLUSIONS

Improvement in data collection on organophosphate poisoning is essential to properly measure the burden of the problem. More effective regulatory controls for pesticide use are needed in South Africa.

Knowledge and Practices Relating to Acute Pesticide Poisoning Among Health Care Providers in Selected Regions of Tanzania

BACKGROUND

Acute pesticide poisoning (APP) is commonly underdiagnosed in Tanzania. Studies in developing countries suggest that a lack of diagnostic skills among health care providers (HCPs) undermines surveillance for APP. This study aimed at characterizing experience and skills of Tanzanian HCPs regarding APP diagnosis and management.

METHODOLOGY

The population included HCPs responsible for managing APP in Kilimanjaro and Arusha regions (n = 91). The resulting sample included 66 respondents (response rate: 73%). The data were collected in 2005 using a standardized questionnaire.

RESULTS

Half of all respondents (50%) reported handling at least 1 APP case with 15% reporting handling more than 5 cases in the past. Reported experience of handling an APP case was marginally higher in respondents who reported ⩾4 years of work experience in the health sector compared with those with <4 years of work experience (odds ratio = 1.32; 95% confidence interval = 0.9-1.5). Most of the respondents had high knowledge of exposure routes, reporting awareness of oral (98.5%), inhalational (93.9%), and dermal (77%) routes. The study revealed low awareness of pesticide classification by chemical groups (29%) or World Health Organization hazard (0%) and weak knowledge on pesticide label instructions (55%). Organophosphates accounted for 35% of the pesticide products reported by respondents as being responsible for poisoning. Some treatment options were incorrectly reported as first aid options, and some reported first aid options were wrong or inappropriate.

CONCLUSIONS

The study revealed that HCPs in northern Tanzania lack adequate skills to diagnose and manage APP. For effective surveillance of APP, there is a need to include training on hazards, classification, diagnosis, and health effects in the training programmes for all HCPs in Tanzania.

Undereporting of acute pesticide poisoning in Tanzania: modelling results from two cross-sectional studies

BACKGROUND

Acute pesticide poisoning (APP) is known to cause serious injuries to end users globally but the magnitude of this problem in Tanzania is not well known. This study aimed to determine the extent and pattern of underreporting of APP in Tanzania to inform the development of a surveillance system and appropriate interventions.

METHODS

This study integrates findings from two recent Tanzanian studies. A household survey established the proportion of poisoned farmers in a typical rural area who reported to hospital for a pesticide poisoning. Only 5 of the 112 farmers who reported attending hospital due to poisonings could be traced in medical records at the facilities they claimed to have attended. The 95% confidence interval for this ratio (5/112) was used to generate a high and low boundary for the estimates. Three under-estimation factors were generated for sensitivity analysis to adjust for under-reporting. A review of health facilities in three regions of Tanzania collected prospective data on admissions for APP in 2006 to generate population-based APP incidence rates stratified by circumstances of poisoning (occupational, accidental, suicide, and unknown). Sensitivity analysis was conducted involving adjustment for high and low boundaries of the under-reporting of occupational APP and an adjustment for different scenario allocations of cases with 'unknown' circumstances to different combinations of known circumstances.

RESULTS

The study estimated the rate of occupational poisoning as ranging from 11.3-37.7 cases/million to 84.3-279.9 cases per million. The rate of all poisonings (occupational and non-occupational) ranged from 24.45-48.01 cases per million to 97.37-290.29 cases per million. Depending on the choice of scenario and under-reporting correction factor used, occupational APP could comprise from 52.2 to 96% of all APP cases.

CONCLUSION

The study confirms that data on APP in Tanzanian hospitals are poorly reported and that occupational circumstances are particularly overlooked in routine facility-based surveillance. Occupational APP needs to be taken more seriously in addressing prevention measures. A comprehensive surveillance system for APP should consider multiple data sources including community self-reporting in order to achieve better coverage.

Pesticide retailers' knowledge and handling practices in selected towns of Tanzania

BACKGROUND

Approximately 300 pesticide retailers are currently registered in Tanzania. Inadequate knowledge and unsafe handling practices among retailers may contribute to human pesticide exposure and environmental contamination. This study investigated pesticide retailers' qualifications, work experience, safety practices and the products distributed so as to identify opportunities for preventing Acute Pesticide Poisoning (APP).

METHODOLOGY

In 2005, employees of pesticide retail firms in six Tanzanian towns were surveyed using a semi-structured questionnaire and physical inspection of premises. In addition, information on products distributed in 2004 and 2005 was collected from Arusha and Arumeru firms to assess potential risk posed for end-users.

RESULTS

More than half of the participating firms (58.6%) were not registered. Most agents on sale in Arusha and Arumeru were hazardous products including WHO Class I and II products (61.7%) and the mean number of cholinesterase inhibiting agents was 5.8 (range 2-8). Major deficiencies found included semi-trained staff (52%), lack of first-aid kits (38.6%), repacking and decanting of pesticides into smaller unlabelled containers (25.3%), lack of fire-fighting equipment (22.6%) and distribution of unregistered products (9.3%). Compared to unregistered companies, those companies that were registered were more likely to report practicing safe container disposal (40% versus 19%; p = 0.06) and to have an absence of leaking containers (36% versus 15%; p = 0.04).

CONCLUSION

Pesticide distribution in Tanzania was accompanied by many unsafe practices that may contribute to the burden from APP, not only affecting the distributors but also farmers who buy and use these products. Market pressures appear to be encouraging decanting of pesticides to enable retailers to make profits. Registration of firms appears to be associated with safer practices. Comprehensive interventions to strengthen enforcement mechanisms by increasing the number of pesticide inspectors, ensuring adequate financial support for enforcement activities and providing training opportunities for pesticide retailers and the end users are strongly recommended.