• 1.

    Pryce J, Richardson M & Lengeler C 2018. Insecticide-treated nets for preventing malaria. Cochrane Database Syst Rev 11: CD000363.

  • 2.

    Wangdi K, Furuya-Kanamori L, Clark J, Barendregt JJ, Gatton ML, Banwell C, Kelly GC, Doi SAR & Clements ACA 2018. Comparative effectiveness of malaria prevention measures: a systematic review and network meta-analysis. Parasit Vectors 11: 210.

    • Search Google Scholar
    • Export Citation
  • 3.

    Dolan C, BenYishay A, Grepin K, Tanner J, Kimmel A, Wheeler D & McCord G 2019. The impact of an insecticide treated bednet campaign on all-cause child mortality: a geospatial impact evaluation from the Democratic Republic of the Congo. PLoS One 14: e0212890.

    • Search Google Scholar
    • Export Citation
  • 4.

    WHO , 2021. Updating WHO’s Global Strategy for Malaria. Available at: https://www.who.int/news/item/01-02-2021-updating-who-s-global-strategy-for-malaria. Accessed February 28, 2021.

  • 5.

    Kilian A, Obi E, Mansiangi P, Abílio AP, Haji KA, Blaufuss S, Olapeju B, Babalola S & Koenker H 2021. Variation of physical durability between LLIN products and net use environments: summary of findings from four African countries. Malar J 20: 26.

    • Search Google Scholar
    • Export Citation
  • 6.

    Briet O et al., 2020. Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity. Malar J 19: 310.

    • Search Google Scholar
    • Export Citation
  • 7.

    Koenker H, Kilian A, De Boyl C, Onyefunafoa E, Selby R, Abeku T, Fotheringham M & Lynch M 2014. What happens to lost nets: a multi-country analysis of reasons for LLIN attrition using 14 household surveys in four countries. Malar J 13: 464.

    • Search Google Scholar
    • Export Citation
  • 8.

    Santos EM, Coalson JE, Munga S, Agawo M, Jacobs ET, Klimentidis YC, Hayden MH & Ernst KC 2020. “After those nets are torn, most people use them for other purposes”: an examination of alternative bed net use in western Kenya. Malar J 19: 272.

    • Search Google Scholar
    • Export Citation
  • 9.

    Ramanantsoa A, Wilson-Barthes M, Rahenintsoa R, Hoibak S, Ranaivoharimina H, Rahelimalala MD, Rakotomanga A, Finlay A, Muela Ribera J & Peeters Grietens K 2017. Can the collection of expired long-lasting insecticidal nets reduce their coverage and use? Sociocultural aspects related to LLIN life cycle management and use in four districts in Madagascar. Malar J 16: 404.

    • Search Google Scholar
    • Export Citation
  • 10.

    Okumu F, Finda MF, Koenraadt CJM, Spitzen J & Takken W Innovative Strategies for Vector Control - Ecology and Control of Vector-Borne Diseases. Wageiningen, The Netherlands: Wageningen Academic Publishers. 6: 3357.

    • Search Google Scholar
    • Export Citation
  • 11.

    Okumu F 2020. The fabric of life: what if mosquito nets were durable and widely available but insecticide-free? Malar J 19: 260.

  • 12.

    Paaijmans KP & Huijben S 2020. Taking the “I” out of LLINs: Using insecticides in vector control tools other than long-lasting nets to fight malaria. Malar J 19: 73.

    • Search Google Scholar
    • Export Citation
  • 13.

    WHO , 2014. WHO Recommendations on the Sound Management of Old Long-lasting Insecticidal Nets. Available at: http://deliver.jsi.com/dlvr_content/resources/allpubs/countryreports/Mada_LLIN_Recy_Pilo.pdf. Accessed February 28, 2021.

  • 14.

    RBM Partnership to End Malaria , 2020. 2 Billion Mosquito Nets Delivered Worldwide Since 2004. Available at: https://endmalaria.org/news/2-billion-mosquito-nets-delivered-worldwide-2004. Accessed February 28, 2021.

  • 15.

    Nielsen TD, Hasselbalch J, Holmberg K & Stripple J 2020. Politics and the plastic crisis: a review throughout the plastic life cycle. Wiley Interdiscip Rev Energy Environ 9: e360.

    • Search Google Scholar
    • Export Citation
  • 16.

    Rhodes C 2018. Plastic pollution and potential solutions. Sci Prog 101: 207260.

  • 17.

    Rasool F et al., 2021. Isolation and characterization of human pathogenic multidrug resistant bacteria associated with plastic litter collected in Zanzibar. J Hazard Mater 405: 124591.

    • Search Google Scholar
    • Export Citation
  • 18.

    Imran M, Das K & Naik M 2019. Co-selection of multi-antibiotic resistance in bacterial pathogens in metal and microplastic contaminated environments: an emerging health threat. Chemosphere 215: 846857.

    • Search Google Scholar
    • Export Citation
  • 19.

    Short R, Gurung R, Rowcliffe M, Hill N & Milner-Gulland EJ 2018. The use of mosquito nets in fisheries: a global perspective. PLoS One 13: e0191519.

  • 20.

    Little EE, Dwyer FJ, Fairchild JF, Delonay AJ & Zajicejk JL 1993. Survival of bluegill and their behavioral responses during continuous and pulsed exposures to esfenvalerate, a pyrethroid insecticide. Environ Toxicol Chem 12: 871878.

    • Search Google Scholar
    • Export Citation
  • 21.

    Larsen DA, Makaure J, Ryan SJ, Stewart D, Traub A, Welsh R, Love DH & Bisesi JH Jr 2021. Implications of insecticide-treated mosquito net fishing in lower income countries. Environ Health Perspect 129: 16.

    • Search Google Scholar
    • Export Citation
  • 22.

    Vengayil DT, Singh J, Singh AL, Das VK & Singh PB 2011. Bioaccumulation of carbamate and pyrethroid insecticides in fishes of the River Gomti at Jaunpur during breeding season. J Ecophysiol Occup Health 11: 18.

    • Search Google Scholar
    • Export Citation
  • 23.

    Burns CJ & Pastoor TP 2018. Pyrethroid epidemiology: a quality-based review. Crit Rev Toxicol 48: 297311.

  • 24.

    Bao W, Liu B, Simonsen DW & Lehmler HJ 2020. Association between exposure to pyrethroid insecticides and risk of all-cause and cause-specific mortality in the general US adult population. JAMA Intern Med 180: 367374.

    • Search Google Scholar
    • Export Citation
  • 25.

    Park J, Park SK & Choi YH 2019. Environmental pyrethroid exposure and diabetes in U.S. adults. Environ Res 172: 399407.

  • 26.

    Jones BL & Unsworth RKF 2020. The perverse fisheries consequences of mosquito net malaria prophylaxis in East Africa. Ambio 49: 12571267.

  • 27.

    RBM Partnership to End Malaria Social Behavior Change Communication Working Group , Alliance for Malaria Prevention Emerging Issues Working Group , RBM Partnership to End Malaria Vector Control Working Group LLIN Priorities Work Stream , 2018. Consensus Statement on Repurposing ITNs: Applications for BCC Messaging and Actions at the Country Level. Available at: https://www.vector-works.org/wp-content/uploads/Consensus-Statement-Repurposing-of-ITNs-2018-11-28.pdf. Accessed July 21, 2021.

 
 
 
 

 

 
 
 

 

 

 

 

 

 

The Unsustainability of Long-Lasting Insecticidal Nets

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  • 1 Department of Applied Health, Southern Illinois University Edwardsville, Edwardsville, Illinois

ABSTRACT.

Long-lasting insecticidal nets (LLINs) are highly effective tools for malaria prevention, and it is clear bed nets are necessary. However, given the environmental concerns of the production, distribution, and disposal of LLINs, the malaria prevention community should look to design sturdier nets that last longer and are made of more sustainable materials to reduce harmful environmental impacts in a time when addressing climate change is urgent. We discuss concerns related to plastic pollution and the environmental health of LLINs in their current form, while recognizing the absolute importance of bed nets for malaria prevention. We call for conversation and innovation among all those involved in malaria prevention to address the unsustainability of LLINs and to maximize the resources available for malaria prevention in a climate of competing global health priorities.

INTRODUCTION

The progress made in global malaria prevention by insecticide-treated nets (ITNs) and subsequent implementation of long-lasting insecticidal nets (LLINs) is remarkable. There is robust evidence that ITNs and LLINs have reduced all-cause child mortality significantly compared with no nets and untreated nets,1 and nets appear to be the most effective prevention intervention compared with other methods.2 In the Democratic Republic of the Congo alone, ITNs are attributed to a 41% reduction in child mortality risk.3 LLINs are essential tools for malaria control proven to save lives, yet stalling progress in reducing malaria morbidity and mortality4 is a contemporary problem that requires continuous improvement in malaria prevention strategies. Given more recent attention on LLIN durability,5,6 repurposing,7,8 recycling,9 and questioning the necessity of insecticides in bed nets,1012 it is also time to assess LLINs from an environmental health perspective. How can LLINs—or, more broadly, bed nets—be improved?

PLASTIC POLLUTION

One attribute of LLINs needing attention is the effect of their production and disposal on the environment. LLINs, along with their packaging, are made of nonbiodegradable plastic materials,13 and a single LLIN contains the amount of plastic polymer equivalent to 40 to 50 plastic bags.9 Since 2004, more than two billion ITNs have been distributed globally.14 Because new nets must be distributed every 3 to 5 years, this perpetual production of LLINs and their packaging materials relies on a large amount of plastic polymer. Between 6% and 9% of global gas and oil production goes toward plastic production and is increasing.15,16 Eventually, all LLINs end up as waste, and often as plastic pollution.

Not only should we work to reduce our reliance on the production of plastic products, we also must consider the public health implications of plastic disposal. In addition to the issues of plastic pollution in the oceans, and effects on aquatic life and ecosystems, there are also immediate public health concerns. For example, multidrug-resistant bacteria were recently found on plastic pollution collected from beaches in Zanzibar.17 Plastic pollution may serve as an environmental source increasing the prevalence of multidrug-resistant pathogens18 and is a particular infectious disease concern among individuals who collect or clean up plastic waste. Without proper waste disposal, plastic pollution poses a serious threat to environmental and human health. It is worth exploring more environmentally sustainable ways to produce and distribute LLINs. Is there a balance to be struck between low production costs and more environmentally responsible materials? Local production of nets made with more sustainable materials is worth exploring, particularly because there are also calls to re-evaluate the use of insecticides in nets.11,12

ENVIRONMENTAL HEALTH

The use of plastic is not just a problem resulting from consumption during production; it is also a concern for net disposal. There are not enough incinerators for the proper disposal of LLINs, and many end up being burned out in the open. The WHO recommends LLINs should not be discarded in the open or in or near water sources.13 Burning in the open results in toxic dioxin exposures from burning the plastic material.13 Exposure to the compounds from burning plastic and from burning residual insecticides is a concern for human health. Even if nets are not burned, residual insecticides can leach into the environment and cause ecological damage, potentially impacting food production, worsening food insecurity, and affecting the same social determinants of health that are risk factors for malaria in the first place.

The use of LLINs for fishing is one of the greatest net concerns that affect ecology and food security negatively. Although the use of LLINs for fishing purposes is largely confined to areas where fishing is a major economic activity19 (and thus not a reason for widespread concern), it remains an issue worth addressing. The residual insecticide on the nets has been found to be toxic to aquatic organisms, particularly fish.13 Observed effects include decreased egg fertilization rates20 and overall declines in fish productivity.21 Understanding potential human health outcomes from LLINs used as fishing nets is a concern that needs more in-depth research.21 Bioconcentration of the residual insecticide for LLINs is a concern because of pyrethroids having been found in aquatic species.22 There is also evidence to suggest an association between pyrethroid exposure and human neurocognitive development,23 increased cardiovascular disease,24 and diabetes in humans,25 although we need to learn more about exposure levels, pathways, and thresholds of toxicity in humans.

Insecticide toxicity to fish populations is ultimately a concern for food security in areas where fishing with LLINs is a common practice. Adding to the concern is the small mesh size of LLINs, which have caused observed decreases in fish populations in Mozambique.26 Nets with small mesh size capture smaller fish, preventing fish populations from replenishing. This stress on the fish populations, coupled with insecticide toxicity, is an environmental health and food security concern related to LLINs that needs to be further studied and addressed.

CONCLUSION AND SOLUTIONS TO EXPLORE

There is no doubt that bed nets are important malaria prevention tools. However, it is time to consider the ecological and environmental health challenges with the current model of LLIN production, distribution, and disposal. From overreliance on plastic materials to the environmental health concerns during improper net disposal and food security concerns where fishing with LLINs is common practice, there is much to consider. We need a collective commitment among all who do and can play a role in malaria prevention to innovate toward sustainability—sustainability of interventions and environmental sustainability. Ultimately, we must continue to focus malaria prevention strategies further upstream in the prevention pipeline to continue to make gains toward elimination while being the best stewards of available resources in the fight against malaria. The following are questions and potential solutions we believe are worth further exploration:

  1. 1.Is it possible to hire local tailors to do net repairs to help maintain coverage and use of nets in between distributions over longer periods of time?
  2. 2.Is it feasible to reduce plastic use in LLIN packaging by bundling multiple nets per package and/or by finding new ways to package nets prior to distribution?
  3. 3.There is a need to continue to study the necessity of insecticides in nets. Are more physically durable, untreated nets just as effective as LLINs?
  4. 4.Is it possible, desirable, and cost-effective to manufacture nets locally using more sustainable non-plastic materials? What materials are readily available?
  5. 5.In areas where fishing is a major economic activity, could appropriate fishing nets be distributed alongside bed net distributions to reduce the use of LLINs in fishing? (See “Acknowledgments.”)
  6. 6.We recommend continued promotion of beneficial net repurposing.27
  7. 7.Can we collect discarded nets and manufacture them into other useful materials for malaria prevention (window screens, eave screens, and so on)?
  8. 8.Do LLINs discarded in the open environment pose a risk to multidrug-resistant bacterial infections? What is the magnitude of risk?

ACKNOWLEDGMENTS

The question Why not give people fishing nets with their bed nets? is not our original idea. This idea was posed by Dr. Elizabeth Jacobs during the dissertation defense of E.S. and is something E.S. has been thinking about since. Thank you for the idea Dr. Jacobs!

References

  • 1.

    Pryce J, Richardson M & Lengeler C 2018. Insecticide-treated nets for preventing malaria. Cochrane Database Syst Rev 11: CD000363.

  • 2.

    Wangdi K, Furuya-Kanamori L, Clark J, Barendregt JJ, Gatton ML, Banwell C, Kelly GC, Doi SAR & Clements ACA 2018. Comparative effectiveness of malaria prevention measures: a systematic review and network meta-analysis. Parasit Vectors 11: 210.

    • Search Google Scholar
    • Export Citation
  • 3.

    Dolan C, BenYishay A, Grepin K, Tanner J, Kimmel A, Wheeler D & McCord G 2019. The impact of an insecticide treated bednet campaign on all-cause child mortality: a geospatial impact evaluation from the Democratic Republic of the Congo. PLoS One 14: e0212890.

    • Search Google Scholar
    • Export Citation
  • 4.

    WHO , 2021. Updating WHO’s Global Strategy for Malaria. Available at: https://www.who.int/news/item/01-02-2021-updating-who-s-global-strategy-for-malaria. Accessed February 28, 2021.

  • 5.

    Kilian A, Obi E, Mansiangi P, Abílio AP, Haji KA, Blaufuss S, Olapeju B, Babalola S & Koenker H 2021. Variation of physical durability between LLIN products and net use environments: summary of findings from four African countries. Malar J 20: 26.

    • Search Google Scholar
    • Export Citation
  • 6.

    Briet O et al., 2020. Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity. Malar J 19: 310.

    • Search Google Scholar
    • Export Citation
  • 7.

    Koenker H, Kilian A, De Boyl C, Onyefunafoa E, Selby R, Abeku T, Fotheringham M & Lynch M 2014. What happens to lost nets: a multi-country analysis of reasons for LLIN attrition using 14 household surveys in four countries. Malar J 13: 464.

    • Search Google Scholar
    • Export Citation
  • 8.

    Santos EM, Coalson JE, Munga S, Agawo M, Jacobs ET, Klimentidis YC, Hayden MH & Ernst KC 2020. “After those nets are torn, most people use them for other purposes”: an examination of alternative bed net use in western Kenya. Malar J 19: 272.

    • Search Google Scholar
    • Export Citation
  • 9.

    Ramanantsoa A, Wilson-Barthes M, Rahenintsoa R, Hoibak S, Ranaivoharimina H, Rahelimalala MD, Rakotomanga A, Finlay A, Muela Ribera J & Peeters Grietens K 2017. Can the collection of expired long-lasting insecticidal nets reduce their coverage and use? Sociocultural aspects related to LLIN life cycle management and use in four districts in Madagascar. Malar J 16: 404.

    • Search Google Scholar
    • Export Citation
  • 10.

    Okumu F, Finda MF, Koenraadt CJM, Spitzen J & Takken W Innovative Strategies for Vector Control - Ecology and Control of Vector-Borne Diseases. Wageiningen, The Netherlands: Wageningen Academic Publishers. 6: 3357.

    • Search Google Scholar
    • Export Citation
  • 11.

    Okumu F 2020. The fabric of life: what if mosquito nets were durable and widely available but insecticide-free? Malar J 19: 260.

  • 12.

    Paaijmans KP & Huijben S 2020. Taking the “I” out of LLINs: Using insecticides in vector control tools other than long-lasting nets to fight malaria. Malar J 19: 73.

    • Search Google Scholar
    • Export Citation
  • 13.

    WHO , 2014. WHO Recommendations on the Sound Management of Old Long-lasting Insecticidal Nets. Available at: http://deliver.jsi.com/dlvr_content/resources/allpubs/countryreports/Mada_LLIN_Recy_Pilo.pdf. Accessed February 28, 2021.

  • 14.

    RBM Partnership to End Malaria , 2020. 2 Billion Mosquito Nets Delivered Worldwide Since 2004. Available at: https://endmalaria.org/news/2-billion-mosquito-nets-delivered-worldwide-2004. Accessed February 28, 2021.

  • 15.

    Nielsen TD, Hasselbalch J, Holmberg K & Stripple J 2020. Politics and the plastic crisis: a review throughout the plastic life cycle. Wiley Interdiscip Rev Energy Environ 9: e360.

    • Search Google Scholar
    • Export Citation
  • 16.

    Rhodes C 2018. Plastic pollution and potential solutions. Sci Prog 101: 207260.

  • 17.

    Rasool F et al., 2021. Isolation and characterization of human pathogenic multidrug resistant bacteria associated with plastic litter collected in Zanzibar. J Hazard Mater 405: 124591.

    • Search Google Scholar
    • Export Citation
  • 18.

    Imran M, Das K & Naik M 2019. Co-selection of multi-antibiotic resistance in bacterial pathogens in metal and microplastic contaminated environments: an emerging health threat. Chemosphere 215: 846857.

    • Search Google Scholar
    • Export Citation
  • 19.

    Short R, Gurung R, Rowcliffe M, Hill N & Milner-Gulland EJ 2018. The use of mosquito nets in fisheries: a global perspective. PLoS One 13: e0191519.

  • 20.

    Little EE, Dwyer FJ, Fairchild JF, Delonay AJ & Zajicejk JL 1993. Survival of bluegill and their behavioral responses during continuous and pulsed exposures to esfenvalerate, a pyrethroid insecticide. Environ Toxicol Chem 12: 871878.

    • Search Google Scholar
    • Export Citation
  • 21.

    Larsen DA, Makaure J, Ryan SJ, Stewart D, Traub A, Welsh R, Love DH & Bisesi JH Jr 2021. Implications of insecticide-treated mosquito net fishing in lower income countries. Environ Health Perspect 129: 16.

    • Search Google Scholar
    • Export Citation
  • 22.

    Vengayil DT, Singh J, Singh AL, Das VK & Singh PB 2011. Bioaccumulation of carbamate and pyrethroid insecticides in fishes of the River Gomti at Jaunpur during breeding season. J Ecophysiol Occup Health 11: 18.

    • Search Google Scholar
    • Export Citation
  • 23.

    Burns CJ & Pastoor TP 2018. Pyrethroid epidemiology: a quality-based review. Crit Rev Toxicol 48: 297311.

  • 24.

    Bao W, Liu B, Simonsen DW & Lehmler HJ 2020. Association between exposure to pyrethroid insecticides and risk of all-cause and cause-specific mortality in the general US adult population. JAMA Intern Med 180: 367374.

    • Search Google Scholar
    • Export Citation
  • 25.

    Park J, Park SK & Choi YH 2019. Environmental pyrethroid exposure and diabetes in U.S. adults. Environ Res 172: 399407.

  • 26.

    Jones BL & Unsworth RKF 2020. The perverse fisheries consequences of mosquito net malaria prophylaxis in East Africa. Ambio 49: 12571267.

  • 27.

    RBM Partnership to End Malaria Social Behavior Change Communication Working Group , Alliance for Malaria Prevention Emerging Issues Working Group , RBM Partnership to End Malaria Vector Control Working Group LLIN Priorities Work Stream , 2018. Consensus Statement on Repurposing ITNs: Applications for BCC Messaging and Actions at the Country Level. Available at: https://www.vector-works.org/wp-content/uploads/Consensus-Statement-Repurposing-of-ITNs-2018-11-28.pdf. Accessed July 21, 2021.

Author Notes

Address correspondence to Ellen M. Santos, Department of Applied Health, Southern Illinois University Edwardsville, 1 Hairpin Dr., Edwardsville, IL 62026. E-mail: elsanto@siue.edu

Authors’ addresses: Ellen M. Santos and Tatyana M. Curtis, Southern Illinois University Edwardsville, Applied Health, Edwardsville, IL, E-mails: elsanto@siue.edu and tcurtis@siue.edu.

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