Rising bed bug insecticide poisonings demand safer pest control methods, French study reveals

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Jul 24 2024

In a recent study published in the journal Scientific Reports, researchers explored the public health implications of infestations of bed bugs, such as Cimex lectularius L. and Cimex hemipterus F., and the associated misuse of chemical insecticides in urban areas.

Their findings indicate that non-professionals' increased use of potentially harmful insecticides has led to a rise in poisoning incidents, highlighting the urgent need for safer and more sustainable pest management strategies.

Study: Trends in poisoning associated with the use of insecticides for bed bug infestations: a 20-year retrospective study in France. Image Credit: Tomasz Klejdysz / Shutterstock

Background

Bed bugs are significant pests, particularly in temperate and tropical regions. They were common in the early 20th century but became rare in developed countries with the introduction of powerful insecticides.

Since the late 1990s, bed bugs have seen a resurgence globally due to resistance to these insecticides, inadequate pest control methods, and increased international travel. While bed bugs do not spread diseases, their bites cause itchy skin reactions and significant mental distress, affecting quality of life and creating financial burdens.

 Chemical insecticides are widely used but have led to resistance problems. Misuse of these insecticides can result in poisoning, with symptoms ranging from mild to severe.

About the study

Due to concerns about insecticide poisoning, researchers analyzed reports of human toxicity related to bed bug insecticides. The French Poison Control Centers (FPCC) collected these from 1999 to 2021.

The FPCC, as part of a national safety program, operates a hotline for reporting chemical exposures. This information is anonymously stored by a national database that is overseen by the French Ministry of Health.

Insecticide products are identified using the French National Database of Products and Compositions (FNDPC), listing the ingredients and brand names of all products available for sale in France.

Researchers identified cases involving bed bug insecticides by looking for the French term for bed bugs ("punaise") in the FNDP records. Only cases specifically mentioning bed bugs were included. Data on patient age, sex, exposure details (product used and circumstances), and symptoms were gathered.

Exposure was classified as 'direct' if a case occurred during use and 'indirect' if it took place afterward. The severity of the poisoning was categorized using a standard scoring system ranging from no symptoms to death.

Findings

Between 1999 and 2021, the FPCC recorded 1,056 cases of exposure to bed bug insecticides, with the first incidence in 2007. Reports increased slowly until mid-2016 and then surged; they peaked in mid-2019. Nearly 40% of incidents occurred from July to September, and most cases (50%) were reported around Paris, despite the region having less than 15% of France's population.

Temporal trends in the number of cases of exposure to insecticides used to treat bed bug infestations reported to French Poison Control Centers (2007–2021): by month (green bars), quarter (orange line), and year (red line).

Among patients, 66% were female, while 34% were male, with a median age of 35. Direct exposure occurred in 51% of cases, mainly in private homes (90%). Only a small number of exposures (less than 1%) involved professional applicators.

Most exposures (over 90%) involved chemical insecticides, and in some cases, banned substances were used. Researchers were unable to identify the active ingredient in the pesticide in about one-fourth of cases.

Symptoms were reported in 76% of cases, with respiratory issues like shortness of breath and coughing being the most common, along with headaches, skin irritations, and digestive problems. Most symptomatic patients (99%) had mild symptoms, but there were 12 severe cases, including one fatality. Four severe cases involved unauthorized insecticides.

Conclusions

Researchers analyzed 1,056 cases where individuals were exposed to insecticides while treating bed bug infestations that were submitted to the FPCC from 2007 to 2021. They found a significant increase in cases from 2016, with a peak in 2019 and a higher frequency of reports during the summer.

Most cases were from major urban areas, including Paris. While most symptoms were mild, vulnerable individuals, including older adults, children, and people with asthma, experienced more severe reactions. The study highlighted issues like premature reentry and misuse of insecticides, leading to higher exposure.

The temporal trends identified in this study are similar to those observed in other parts of the world. However, researchers noted concerns that this method of data collection could lead to underestimations in the incidence of cases.

The study's strengths include its extensive data span and valuable insights into exposure patterns. However, it faced limitations like inconsistent data collection and the inability to conduct quantitative analyses. The use of unauthorized insecticides and their severe effects, including a fatality, underscored the challenges of bed bug management due to pesticide resistance.

Future research should focus on the long-term health impacts of pesticide exposure, particularly pyrethroids, and the mental health effects of bed bug infestations, which can include panic, anxiety,  and disturbances to sleep, mood, and work.

The study emphasizes the need for safer and more sustainable pest management practices, prioritizing non-chemical methods and insecticides with lower toxicity.