Background
Pesticide is a collective term for a wide array of chemicals that refers to insecticides, herbicides, fungicides, rodenticides, etc. [
1]. Different types of pesticides are applied to kill insects, rodents, fungi, weed and also used to kill vectors of diseases in public health [
2]. Due to the widespread and inappropriate use of pesticide, pesticide poisoning stands as a serious health problem and remains a significant public health issue. According to WHO data, pesticide poisoning accounts for an estimated 250,000 deaths annually among three million cases worldwide [
3]. Notably, a large proportion of studies on pesticide poisoning were carried out in adults [
4‐
6]. However, pesticides are common poisoning reasons for children especially in the developing countries [
7]. In Egypt from 2009 to 2013, pesticides were the most common agents resulting in moderate or severe toxicity from non-pharmaceutical exposures in children, as well as the most common reason for admission to hospital [
8]. In South African pesticide poisoning accounted for 11% of all paediatric poisoning cases (2003–2008) [
9]. Childhood pesticide poisoning accounted for 37% of all pesticide poisoning calls reported to the National Poison Information Centre of India from 1999 to 2012 according to the All India Institute of Medical Science [
10].
Different to adult pesticide poisoning, childhood pesticide poisoning has some characteristics. Firstly, contaminated food and water, and pest control in the home, yard, and school are all potential sources of children’s exposure [
11]. Children’s behaviors and abilities to interact with their physical environment change during the different stages of growth and development, which can place them at greater risk [
12]. Secondly, children are more vulnerable than adults to pesticide exposure [
12,
13]. Children have rapid growing and developing organ systems, and the long-lasting exposure to pesticides during childhood have been associated with an increased risk of malignancy in adulthood [
14,
15], respiratory symptoms [
16], delays or impairments in language development [
17,
18] and other neurodevelopmental outcomes [
19‐
21]. The health effects of pesticide poisoning for children are an ongoing focus of concern and inquiry. Thus, it is vitally important to pay more attention to child pesticide poisoning.
In China, the pesticide poisoning is one of the major public health issues [
6,
22‐
25]. However, the epidemiological information about pesticide poisoning among children in China is limited. The Occupational Disease Surveillance and Reporting System (ODSRS) has been launched since 2006, which archives registration cases of occupational diseases and pesticide poisoning. Our previous study reported pesticide poisoning and death in adults with age over 20 years previously using the data provided by this system [
26]. In this study, we described the overall epidemiological characteristics of acute childhood pesticide poisoning using the data from pesticide poisoning cases registered with the ODSRS in Zhejiang province, China. This work was a necessary complement to previous report and also provided important messages about pesticide poisoning of children, which should not be ignored. To the best of our knowledge, this is the first retrospective analysis of pesticide poisoning among children in Zhejiang, China.
Discussion
We analyzed the epidemiological characteristics of child pesticide poisoning in this study and our work revealed that pesticide poisoning occurred mostly in rural areas which was consistent with reports in China and other countries [
28‐
30]. This was attributed to common pesticide usage related to agricultural activities in these areas. Pesticides are easily available to rural families.
Organophosphate and carbamate insecticides were the most common pesticides causing child pesticide poisoning in our study, which may be due to their common usage in agriculture and hence their easy availability. Most deaths were from poisoning by dichlorvos, which is one of the most commonly used organophosphates in China [
24]. During the study period, 14 deaths were caused by paraquat, which is a highly efficient herbicide with intense toxicity for humans. Treating paraquat poisoning is very difficult because no specified antidotes exist [
31,
32]. A ban on the production of liquid paraquat took effect in July 2014 and the sale for agricultural use was banned in July 2016 in China. The death rate from herbicides is expected to drop in the next a few years due to this policy.
Our study found that childhood pesticide poisoning was common in the farming season in Zhejiang. In our previous study, we also found more pesticide poisoning and death cases in adult during the farming season in Zhejiang province [
26]. Studies in other countries showed the incidence of pesticide poisoning correlated with pesticide availability due to the season-specific agricultural activities [
9,
29,
33].
Out of all age the groups, pesticide poisoning of infants yielded the highest fatality rate. Infant pesticide poisoning is rare because they are taken good care of by adults with intensive attention and they have limited ability to get access to pesticides by themselves. Most of the cases are due to consumption of contaminated food [
34]. The highest fatality rate in the infant group might be due to their particular vulnerabilities.
The highest frequency of pesticide poisoning was found in the pre-school age group which was consistent with other studies among children [
8‐
10,
35,
36]. This could be due to their inherent inquisitiveness and high “hand to mouth” activity out of curiosity and their exploratory nature [
37]. It is an incontrovertible fact that children are curious about their surroundings and are often unaware of the impending danger. Children at this age may be able to gain access to pesticides, but they have no developed cognitive hazard awareness. The chance of accidental poisoning increased when the pesticides were not safely stored [
10,
33,
38,
39]. Pesticide poisoning of children is mostly preventable if effective preventive strategies are employed. It is important to provide children with a safe environment. This requires better management of pesticides, including labeling of pesticide containers with poison warning stickers, and immediately placing pesticides into safe storage after use. In most developed countries child-resistant packaging has been used for packaging of medications, household chemicals and pesticides, which has proven to be one of the most effective preventive measures against unintentional poisoning of young children [
11]. In China, child-proof caps are not widely used in the packaging of pesticides, which makes pesticides more accessible to kids. Therefore, child-resistant packaging and closures are strongly recommended for pesticide manufacturing and storing in China.
Case numbers dropped significantly for children of school age when they became more aware of pesticide risks and spent less time in unsafe home environments. However, poisoning case numbers rebounded for the adolescent group with an increase also in the fatality rate. Other studies have also found that case number and fatality rates decreased with age, but then increased to a second peak during adolescence [
27,
38]. This was likely related to intentional poisoning aimed at self-harm. Such exposures are an important social problem among adolescents in some Asian countries, including China [
40]. In our study, most of the cases in adolescents were intentional. Thus, suicide by pesticide in adolescents has been a serious public health problem in Zhejiang. More attention should be paid to the mental health of adolescent group.
More boys were poisoned than girls in numbers in our study, which was similar to previous studies [
9,
33,
35], probably as a result of the higher activity of boys. We found female cases were more common in the adolescent group resulting in a conspicuously high number of deaths. These findings were consistent with other studies that found significant associations between adolescent girls and intentional poisoning [
41‐
43]. According to those studies, the higher rate of suicide in adolescent females was correlated with depressive symptoms and romantic disappointment. These conditions were more prominent in girls than in boys. Overall, suicide remains a leading cause of death in adolescent and the ingestion of pesticide is among the most common methods of suicide globally.
Our study shows that it is possible to monitor cases of pesticide poisoning using ODSRS. This database is valuable from public health perspective and for long term monitoring of the effects of pesticides. Still, there are some limitations of this register-based study. The observations in this report are empirical, that is they are based on experience and not on theory or logic. There is no other way to gather this sort of information. The empirical nature of these results does not reveal the causes for the observations. This is an inherent limitation of empirical approach. The nature of our study was descriptive epidemiology. The absolute number could provide some useful information from public health perspectives. Another major limitation of our study is the ODSRS is hospital based and a number of rural clinics are still not included as surveillance sites. Pesticide poisoning was much more common in rural areas. This led to an unknown total population number. In addition, misdiagnosis was often unavoidable due to the lack of useful descriptions about the symptoms of sick children. There might be some out-of-hospital deaths caused by pesticide poisoning which also resulted in under-reporting. And people in severe cases will be transferred to provincial hospitals from rural clinics for better therapy. They are often registered as “survival” instead of being followed up. In addition, some physicians in rural areas may fail to report cases to the system. We will say that the establishment of the ODSRS has improved the reporting rate, but under-reporting still exists. We didn’t register the types of factors leading to poisoning currently. To improve the system and get more useful information, we will suggest add types of poisoning to the data base. For example, some common reasons for unintentional poisoning: inadequate storage places or inappropriate ways of storage for pesticides etc. The detailed information would help us to make strategies to prevent pesticide poisoning of children. We only included child pesticide poisoning in Zhejiang province in this study, which may not represent pesticide poisoning patterns in other provinces in China. Future studies about the reporting rate by the ODSRS in other areas are warranted to better estimate the child pesticide poisoning in China.
Acknowledgements
Not applicable.