A new study has found that seven in 10 pesticide poisoning cases recorded at selected hospitals in Tanzania result from intentional poisoning.
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Pesticide poisoning is one of the most common methods of global suicide, responsible for around 20% all suicide deaths. It is a known problem in Africa, however accurate data remains scarce.
The study, led by the Tanzania Plant Health and Pesticide Authority (TPHPA) and supported by the Centre for Pesticide Suicide Prevention (CPSP), aimed to provide crucial information on pesticide poisoning cases in Tanzania. Researchers examined whether cases were accidental or intentional, assessed case fatality rates, and identified the pesticides responsible.
The study team reviewed 635 cases of pesticide poisoning reported between January 2017 and November 2024 at regional referral hospitals and district hospitals located in five regions of Tanzania: Arusha, Kilimanjaro, Morogoro, Iringa, and Mwanza.
Intentional poisoning with pesticides
The study found that the majority of cases resulted from intentional poisoning. This was particularly common among young adults aged between 16-35 years.
In contrast, most cases of poisoning among children under the age of 15 were accidental.
While “intentional poisoning” does not necessarily mean self-harm or suicide, it is likely that these accounted for the majority of cases. However, hospital records did not consistently include information on the motivation behind intentional poisonings.
These findings are consistent with international research, which shows that intentional pesticide poisoning is a major cause of suicide in rural farming communities, where people have easy access to lethal pesticides.
Pesticides are often stored in homes and gardens. This not only increases the risk of self-harm in moments of crisis, but also raises the likelihood of accidental exposure among children.
Highly hazardous pesticides responsible for deaths
Although most pesticide poisoning patients made a full recovery, nearly a fifth of all cases resulted in death.
The study examined which pesticide was used in each case and the outcomes associated with each one. It found that some pesticides were more deadly than others.
A small number of highly hazardous pesticides (HHPs) – pesticides which cause disproportionate harm to environment and human health – were found to be responsible for a disproportionate share of deaths.
One specific deadly pesticide, paraquat, accounted for nearly half of all deaths recorded in the study. Over 90% of patients with paraquat poisoning did not survive.
Supporting pesticide regulation in Tanzania
Recognising the risks associated with highly toxic pesticides, Tanzania has recently initiated regulatory actions to limit access to the most harmful pesticides.
Earlier this year, Tanzania banned 23 pesticide active ingredients. This includes paraquat, which the study found to be responsible for the majority of deaths.
The study’s findings provide further evidence to support this action and the continued restriction and removal of highly hazardous pesticides.
The study’s lead author and TPHPA researcher Raphael Mwezi said:
“These data give Tanzania a crucial baseline for action. They show that deaths are not evenly distributed across pesticides: a small number of highly hazardous products, particularly paraquat, account for most of the mortality burden. Risk-based regulation, stronger hospital reporting and better clinical preparedness can save lives and help us measure the impact of recent reforms.”
Responding to the study’s findings, CPSP Director Professor Michael Eddleston said:
“This is important research as it provides much needed data to help us understand the problem of pesticide suicides in Tanzania. It clearly shows that intentional pesticide poisoning is a major issue, particularly among young people. We can also see that it is a handful of highly toxic pesticides that are causing disproportionate harm.
“Tanzania has recently taken really important steps to limit access to highly hazardous pesticides. We already know from international evidence that this is an extremely effective way to save lives. We would therefore expect these restrictions to have a significant impact on public health in Tanzania and look forward to working with colleagues in Tanzania to see and monitor the results.”
The study is published in Frontiers in Toxicology.
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