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

Abstract

BackgroundAcute 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.MethodsThis 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.ResultsThe 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.ConclusionThe 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.

Acute pesticide poisoning amongst adolescent girls and women in northern Tanzania

“…The fact that most facilities visited reported poisoning indicates that APP in women is widespread in the study area. Given that APP is under-reported in many developing countries [1,13,45], particularly amongst women [1], it is likely that there are further cases which are not captured due to the absence of an adequate surveillance system.…”

“…Again, this may be a function of under-reporting resulting from the absence of a comprehensive surveillance system for APP in Tanzania as well as misdiagnosis of signs and symptoms of pesticides exposure. Previous research suggests that occupational cases may be missed [1] since farmers do not present to hospitals, especially for less severe poisonings, but rather wait to recover or use alternative treatments [10].…”

“…Zinc phosphide is extremely toxic, causing acute respiratory distress in exposed persons due to the release of phosphine gas when it comes into contact with moisture [59]. However, it is not registered for use in Tanzania and its distribution is therefore illegal, its use being mainly for domestic rats control [1]. Because the main use of this highly hazardous product occurs within households, the proximity to human habitation is likely to increase risks for human poisoning.…”

“…Acute pesticide poisoning (APP) is documented as a serious public health problem in Tanzania [1,2] and other parts of the world [3][4][5][6][7][8][9] due to its adverse human health effects. Evidence of APP occurring in women is documented in studies from Tanzania [2,10], Uganda [11], Kenya [12], South Africa [13,14], India [15], China [16], Nepal [17], Sri Lanka [18], Iran [19] and Ethiopia [20].…”

“…Research on APP amongst women in Tanzania suggests that, firstly, agents reported to be responsible for poisoning include hazardous pesticides, particularly OPs used on food crops [2]. Secondly, although reports of occupational pesticide poisoning are uncommon in health facility records [1], studies have suggested that women may be at high risk for APP, given that women comprise of 80% of the agricultural labour force in Sub-Saharan Africa where pesticides are applied regularly [39].…”