Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea

Rebecca Vinit; Lincoln Timinao; Nakei Bubun; Michelle Katusele; Leanne J. Robinson; Peter Kaman; Muker Sakur; Leo Makita; Lisa Reimer; Louis Schofield; William Pomat; Ivo Mueller; Moses Laman; Tim Freeman; Stephan Karl

doi:10.1038/s41467-020-17456-2

Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea

Rebecca Vinit, Lincoln Timinao, Nakei Bubun, Michelle Katusele, Leanne J. Robinson, Peter Kaman, Muker Sakur, Leo Makita, Lisa Reimer, Louis Schofield, William Pomat, Ivo Mueller, Moses Laman, Tim Freeman, Stephan Karl

Vector Biology

Research output: Contribution to journal › Article › peer-review

39 Citations (Scopus)

Abstract

Background: Papua New Guinea (PNG) has the highest malaria transmission outside of Africa and long-lasting insecticidal nets (LLIN) are the only vector-control tool distributed country-wide. LLIN were introduced into PNG in about 2005 and have been attributed to have had a huge impact on malaria transmission, with reductions in malaria prevalence observed from 15.7% (2008) to 1% (2014). Since 2015, malaria indicators in PNG have risen significantly. Similar trends have been observed in several African nations. In the present study, we observed a drastic reduction in bioefficacy of LLIN collected both from communities (used nets) and prior to use (new nets). We hypothesise that decreased bioefficacy of LLINs is a major contributor to the observed malaria resurgence in PNG and possibly in other parts of the world. Methods: New LLIN in original and unopened packaging (n=192) with a range of manufacturing dates from 2007-2019 were collected either directly from consignments or from households in 15 PNG provinces. Used LLIN (n=40) were collected in 2 provinces, with manufacturing dates ranging from 2008-2017. LLIN were subjected to standard WHO cone bioassays using fully susceptible An. farauti mosquitoes. A subset of LLIN was re-tested using fully susceptible An. gambiae mosquitoes in order to ensure reproducibility of results. Results: Only 7% (95% CI 4-12%) of new LLIN manufactured between 2013-2019 exhibited 100% mortality. However, 84% (95%CI: 65-84%) new nets manufactured in 2012 or before exhibited 100% mortality. Only 29 % of used LLIN less than 3 years old exhibited > 80% 24h-mortality. Results obtained in tests using An. farauti corresponded well with confirmatory tests conducted using An. gambiae. Discussion: Bioefficacy of LLIN in PNG appears to have been highly variable since 2013, with few nets manufactured since 2013 meeting WHO standards. This time-frame coincides with malaria resurgence in the country. These results may have ramifications for LLIN-based malaria control that go beyond the local PNG scenario.

Original language	English
Article number	3646
Pages (from-to)	3646
Journal	Nature Communications
Volume	11
Issue number	1
DOIs	https://doi.org/10.1038/s41467-020-17456-2
Publication status	Published - 20 Jul 2020

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Vinit, R., Timinao, L., Bubun, N., Katusele, M., Robinson, L. J., Kaman, P., Sakur, M., Makita, L., Reimer, L., Schofield, L., Pomat, W., Mueller, I., Laman, M., Freeman, T., & Karl, S. (2020). Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea. Nature Communications, 11(1), 3646. Article 3646. https://doi.org/10.1038/s41467-020-17456-2

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title = "Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea",

abstract = "Background: Papua New Guinea (PNG) has the highest malaria transmission outside of Africa and long-lasting insecticidal nets (LLIN) are the only vector-control tool distributed country-wide. LLIN were introduced into PNG in about 2005 and have been attributed to have had a huge impact on malaria transmission, with reductions in malaria prevalence observed from 15.7\% (2008) to 1\% (2014). Since 2015, malaria indicators in PNG have risen significantly. Similar trends have been observed in several African nations. In the present study, we observed a drastic reduction in bioefficacy of LLIN collected both from communities (used nets) and prior to use (new nets). We hypothesise that decreased bioefficacy of LLINs is a major contributor to the observed malaria resurgence in PNG and possibly in other parts of the world. Methods: New LLIN in original and unopened packaging (n=192) with a range of manufacturing dates from 2007-2019 were collected either directly from consignments or from households in 15 PNG provinces. Used LLIN (n=40) were collected in 2 provinces, with manufacturing dates ranging from 2008-2017. LLIN were subjected to standard WHO cone bioassays using fully susceptible An. farauti mosquitoes. A subset of LLIN was re-tested using fully susceptible An. gambiae mosquitoes in order to ensure reproducibility of results. Results: Only 7\% (95\% CI 4-12\%) of new LLIN manufactured between 2013-2019 exhibited 100\% mortality. However, 84\% (95\%CI: 65-84\%) new nets manufactured in 2012 or before exhibited 100\% mortality. Only 29 \% of used LLIN less than 3 years old exhibited > 80\% 24h-mortality. Results obtained in tests using An. farauti corresponded well with confirmatory tests conducted using An. gambiae. Discussion: Bioefficacy of LLIN in PNG appears to have been highly variable since 2013, with few nets manufactured since 2013 meeting WHO standards. This time-frame coincides with malaria resurgence in the country. These results may have ramifications for LLIN-based malaria control that go beyond the local PNG scenario.",

author = "Rebecca Vinit and Lincoln Timinao and Nakei Bubun and Michelle Katusele and Robinson, \{Leanne J.\} and Peter Kaman and Muker Sakur and Leo Makita and Lisa Reimer and Louis Schofield and William Pomat and Ivo Mueller and Moses Laman and Tim Freeman and Stephan Karl",

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Vinit, R, Timinao, L, Bubun, N, Katusele, M, Robinson, LJ, Kaman, P, Sakur, M, Makita, L, Reimer, L, Schofield, L, Pomat, W, Mueller, I, Laman, M, Freeman, T & Karl, S 2020, 'Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea', Nature Communications, vol. 11, no. 1, 3646, pp. 3646. https://doi.org/10.1038/s41467-020-17456-2

TY - JOUR

T1 - Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea

AU - Vinit, Rebecca

AU - Timinao, Lincoln

AU - Bubun, Nakei

AU - Katusele, Michelle

AU - Robinson, Leanne J.

AU - Kaman, Peter

AU - Sakur, Muker

AU - Makita, Leo

AU - Reimer, Lisa

AU - Schofield, Louis

AU - Pomat, William

AU - Mueller, Ivo

AU - Laman, Moses

AU - Freeman, Tim

AU - Karl, Stephan

PY - 2020/7/20

Y1 - 2020/7/20

N2 - Background: Papua New Guinea (PNG) has the highest malaria transmission outside of Africa and long-lasting insecticidal nets (LLIN) are the only vector-control tool distributed country-wide. LLIN were introduced into PNG in about 2005 and have been attributed to have had a huge impact on malaria transmission, with reductions in malaria prevalence observed from 15.7% (2008) to 1% (2014). Since 2015, malaria indicators in PNG have risen significantly. Similar trends have been observed in several African nations. In the present study, we observed a drastic reduction in bioefficacy of LLIN collected both from communities (used nets) and prior to use (new nets). We hypothesise that decreased bioefficacy of LLINs is a major contributor to the observed malaria resurgence in PNG and possibly in other parts of the world. Methods: New LLIN in original and unopened packaging (n=192) with a range of manufacturing dates from 2007-2019 were collected either directly from consignments or from households in 15 PNG provinces. Used LLIN (n=40) were collected in 2 provinces, with manufacturing dates ranging from 2008-2017. LLIN were subjected to standard WHO cone bioassays using fully susceptible An. farauti mosquitoes. A subset of LLIN was re-tested using fully susceptible An. gambiae mosquitoes in order to ensure reproducibility of results. Results: Only 7% (95% CI 4-12%) of new LLIN manufactured between 2013-2019 exhibited 100% mortality. However, 84% (95%CI: 65-84%) new nets manufactured in 2012 or before exhibited 100% mortality. Only 29 % of used LLIN less than 3 years old exhibited > 80% 24h-mortality. Results obtained in tests using An. farauti corresponded well with confirmatory tests conducted using An. gambiae. Discussion: Bioefficacy of LLIN in PNG appears to have been highly variable since 2013, with few nets manufactured since 2013 meeting WHO standards. This time-frame coincides with malaria resurgence in the country. These results may have ramifications for LLIN-based malaria control that go beyond the local PNG scenario.

AB - Background: Papua New Guinea (PNG) has the highest malaria transmission outside of Africa and long-lasting insecticidal nets (LLIN) are the only vector-control tool distributed country-wide. LLIN were introduced into PNG in about 2005 and have been attributed to have had a huge impact on malaria transmission, with reductions in malaria prevalence observed from 15.7% (2008) to 1% (2014). Since 2015, malaria indicators in PNG have risen significantly. Similar trends have been observed in several African nations. In the present study, we observed a drastic reduction in bioefficacy of LLIN collected both from communities (used nets) and prior to use (new nets). We hypothesise that decreased bioefficacy of LLINs is a major contributor to the observed malaria resurgence in PNG and possibly in other parts of the world. Methods: New LLIN in original and unopened packaging (n=192) with a range of manufacturing dates from 2007-2019 were collected either directly from consignments or from households in 15 PNG provinces. Used LLIN (n=40) were collected in 2 provinces, with manufacturing dates ranging from 2008-2017. LLIN were subjected to standard WHO cone bioassays using fully susceptible An. farauti mosquitoes. A subset of LLIN was re-tested using fully susceptible An. gambiae mosquitoes in order to ensure reproducibility of results. Results: Only 7% (95% CI 4-12%) of new LLIN manufactured between 2013-2019 exhibited 100% mortality. However, 84% (95%CI: 65-84%) new nets manufactured in 2012 or before exhibited 100% mortality. Only 29 % of used LLIN less than 3 years old exhibited > 80% 24h-mortality. Results obtained in tests using An. farauti corresponded well with confirmatory tests conducted using An. gambiae. Discussion: Bioefficacy of LLIN in PNG appears to have been highly variable since 2013, with few nets manufactured since 2013 meeting WHO standards. This time-frame coincides with malaria resurgence in the country. These results may have ramifications for LLIN-based malaria control that go beyond the local PNG scenario.

U2 - 10.1038/s41467-020-17456-2

DO - 10.1038/s41467-020-17456-2

M3 - Article

SN - 2041-1723

VL - 11

SP - 3646

JO - Nature Communications

JF - Nature Communications

IS - 1

M1 - 3646

ER -

Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea

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