A study, led by the Tanzania Plant Health and Pesticide Authority (TPHPA), which found that more than two thirds of pesticide poisoning cases in Tanzania result from intentional poisoning.
Authors: Raphael Mwezi, Joseph Bukalasa, Fredrick Otieno, Rosevera Kombo, Grivin Ochola, Florida Muro, Anicet Honest, Sarah Urasa, Mark Davis, Michael Eddleston, Marieke Dekker, William Howlett, John-Mary Vianney
Published in: Frontiers in Toxicology
Abstract
Background
Pesticide poisoning remains a major public health challenge in low- and middle-income countries, particularly where highly hazardous pesticides (HHPs) remain accessible and toxicovigilance systems are limited. Although Tanzania has recently initiated regulatory actions targeting HHPs, evidence regarding pesticide-specific mortality patterns and clinical outcomes remains scarce. This study assessed clinical outcomes, pesticide-specific case fatality, and mortality risk among pesticide poisoning cases reported in selected Tanzanian hospitals.
Methods
A retrospective cross-sectional study was conducted using hospital records from Regional Referral Hospitals and District Hospitals in Arusha, Kilimanjaro, Morogoro, Iringa, and Mwanza regions between January 2017 and November 2024. Cases were identified through hospital poisoning records, emergency department registers, admission records, and medical files. Information on demographic characteristics, exposure type, pesticide category, and clinical outcomes was extracted using structured electronic forms. Descriptive statistics summarize poisoning characteristics and outcomes. Associations between demographic factors and clinical outcomes were assessed using chi-square tests. Binary logistic regression was used to identify predictors of mortality, and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were reported.
Results
A total of 635 pesticide poisoning cases were included in the analysis. Most patients were male (64.1%) and aged 16–35 years (61.3%). Intentional exposure accounted for 70.2% of cases, while unintentional exposure represented 20.3%. Most patients fully recovered (67.9%; 95% CI: 64.1–71.4), whereas 18.4% (95% CI: 15.5–21.6) died following pesticide poisoning. Paraquat poisoning demonstrated the highest case fatality (93.3%), followed by glyphosate (45.5%) and tefluthrin (33.3%). Compared with lower-risk pesticide exposures, paraquat poisoning was associated with markedly increased odds of death (aOR = 21.5; 95% CI: 9.4–48.2), while glyphosate poisoning was associated with elevated mortality risk (aOR = 5.2; 95% CI: 1.8–14.6). Pesticides with case fatality exceeding 10% contributed 87.3% of all recorded deaths.
Conclusion
Mortality following pesticide poisoning in Tanzania was strongly concentrated among a small number of highly hazardous pesticides, particularly paraquat. These findings support continued restriction and removal of highly hazardous pesticides, strengthening of pesticide-specific surveillance systems, improved clinical toxicology capacity, and enhanced poisoning prevention strategies. Continued monitoring will be important to evaluate the public health impact of recent pesticide regulatory reforms in Tanzania.