Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity
Abstract Background Long-lasting insecticidal nets (LLINs) are the primary malaria prevention and control intervention in many parts of sub-Saharan Africa. While LLINs are expected to last at least 3 years under normal use conditions, they can lose effectiveness because they fall out of use, are dis...
Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
BMC
2020-08-01
|
Series: | Malaria Journal |
Subjects: | |
Online Access: | http://link.springer.com/article/10.1186/s12936-020-03383-6 |
id |
doaj-1c45186a74084aeea5fe36db4ff2c2c2 |
---|---|
record_format |
Article |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Olivier Briet Hannah Koenker Laura Norris Ryan Wiegand Jodi Vanden Eng Alex Thackeray John Williamson John E. Gimnig Filomeno Fortes Martin Akogbeto Anges W. Yadouleton Maurice Ombok M. Nabie Bayoh Themba Mzilahowa Ana Paula Abílio Samuel Mabunda Nelson Cuamba Elhadji Diouf Lassana Konaté Busiku Hamainza Cecilia Katebe-Sakala Gabriel Ponce de León Kwame Asamoa Adam Wolkon Stephen C. Smith Isabel Swamidoss Mike Green Salam Gueye Jules Mihigo Juliette Morgan Ellen Dotson Allen S. Craig Kathrine R. Tan Robert A. Wirtz Tom Smith |
spellingShingle |
Olivier Briet Hannah Koenker Laura Norris Ryan Wiegand Jodi Vanden Eng Alex Thackeray John Williamson John E. Gimnig Filomeno Fortes Martin Akogbeto Anges W. Yadouleton Maurice Ombok M. Nabie Bayoh Themba Mzilahowa Ana Paula Abílio Samuel Mabunda Nelson Cuamba Elhadji Diouf Lassana Konaté Busiku Hamainza Cecilia Katebe-Sakala Gabriel Ponce de León Kwame Asamoa Adam Wolkon Stephen C. Smith Isabel Swamidoss Mike Green Salam Gueye Jules Mihigo Juliette Morgan Ellen Dotson Allen S. Craig Kathrine R. Tan Robert A. Wirtz Tom Smith Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity Malaria Journal Long-lasting insecticidal nets Durability monitoring Vectorial capacity Malaria |
author_facet |
Olivier Briet Hannah Koenker Laura Norris Ryan Wiegand Jodi Vanden Eng Alex Thackeray John Williamson John E. Gimnig Filomeno Fortes Martin Akogbeto Anges W. Yadouleton Maurice Ombok M. Nabie Bayoh Themba Mzilahowa Ana Paula Abílio Samuel Mabunda Nelson Cuamba Elhadji Diouf Lassana Konaté Busiku Hamainza Cecilia Katebe-Sakala Gabriel Ponce de León Kwame Asamoa Adam Wolkon Stephen C. Smith Isabel Swamidoss Mike Green Salam Gueye Jules Mihigo Juliette Morgan Ellen Dotson Allen S. Craig Kathrine R. Tan Robert A. Wirtz Tom Smith |
author_sort |
Olivier Briet |
title |
Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity |
title_short |
Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity |
title_full |
Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity |
title_fullStr |
Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity |
title_full_unstemmed |
Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity |
title_sort |
attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-saharan africa and modelling of their impact on vectorial capacity |
publisher |
BMC |
series |
Malaria Journal |
issn |
1475-2875 |
publishDate |
2020-08-01 |
description |
Abstract Background Long-lasting insecticidal nets (LLINs) are the primary malaria prevention and control intervention in many parts of sub-Saharan Africa. While LLINs are expected to last at least 3 years under normal use conditions, they can lose effectiveness because they fall out of use, are discarded, repurposed, physically damaged, or lose insecticidal activity. The contributions of these different interrelated factors to durability of nets and their protection against malaria have been unclear. Methods Starting in 2009, LLIN durability studies were conducted in seven countries in Africa over 5 years. WHO-recommended measures of attrition, LLIN use, insecticidal activity, and physical integrity were recorded for eight different net brands. These data were combined with analyses of experimental hut data on feeding inhibition and killing effects of LLINs on both susceptible and pyrethroid resistant malaria vectors to estimate the protection against malaria transmission—in terms of vectorial capacity (VC)—provided by each net cohort over time. Impact on VC was then compared in hypothetical scenarios where one durability outcome measure was set at the best possible level while keeping the others at the observed levels. Results There was more variability in decay of protection over time by country than by net brand for three measures of durability (ratios of variance components 4.6, 4.4, and 1.8 times for LLIN survival, use, and integrity, respectively). In some countries, LLIN attrition was slow, but use declined rapidly. Non-use of LLINs generally had more effect on LLIN impact on VC than did attrition, hole formation, or insecticide loss. Conclusions There is much more variation in LLIN durability among countries than among net brands. Low levels of use may have a larger impact on effectiveness than does variation in attrition or LLIN degradation. The estimated entomological effects of chemical decay are relatively small, with physical decay probably more important as a driver of attrition and non-use than as a direct cause of loss of effect. Efforts to maximize LLIN impact in operational settings should focus on increasing LLIN usage, including through improvements in LLIN physical integrity. Further research is needed to understand household decisions related to LLIN use, including the influence of net durability and the presence of other nets in the household. |
topic |
Long-lasting insecticidal nets Durability monitoring Vectorial capacity Malaria |
url |
http://link.springer.com/article/10.1186/s12936-020-03383-6 |
work_keys_str_mv |
AT olivierbriet attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT hannahkoenker attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT lauranorris attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT ryanwiegand attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT jodivandeneng attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT alexthackeray attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT johnwilliamson attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT johnegimnig attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT filomenofortes attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT martinakogbeto attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT angeswyadouleton attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT mauriceombok attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT mnabiebayoh attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT thembamzilahowa attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT anapaulaabilio attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT samuelmabunda attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT nelsoncuamba attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT elhadjidiouf attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT lassanakonate attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT busikuhamainza attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT ceciliakatebesakala attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT gabrielponcedeleon attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT kwameasamoa attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT adamwolkon attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT stephencsmith attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT isabelswamidoss attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT mikegreen attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT salamgueye attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT julesmihigo attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT juliettemorgan attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT ellendotson attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT allenscraig attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT kathrinertan attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT robertawirtz attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity AT tomsmith attritionphysicalintegrityandinsecticidalactivityoflonglastinginsecticidalnetsinsubsaharanafricaandmodellingoftheirimpactonvectorialcapacity |
_version_ |
1724474052004806656 |
spelling |
doaj-1c45186a74084aeea5fe36db4ff2c2c22020-11-25T03:54:23ZengBMCMalaria Journal1475-28752020-08-0119111510.1186/s12936-020-03383-6Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacityOlivier Briet0Hannah Koenker1Laura Norris2Ryan Wiegand3Jodi Vanden Eng4Alex Thackeray5John Williamson6John E. Gimnig7Filomeno Fortes8Martin Akogbeto9Anges W. Yadouleton10Maurice Ombok11M. Nabie Bayoh12Themba Mzilahowa13Ana Paula Abílio14Samuel Mabunda15Nelson Cuamba16Elhadji Diouf17Lassana Konaté18Busiku Hamainza19Cecilia Katebe-Sakala20Gabriel Ponce de León21Kwame Asamoa22Adam Wolkon23Stephen C. Smith24Isabel Swamidoss25Mike Green26Salam Gueye27Jules Mihigo28Juliette Morgan29Ellen Dotson30Allen S. Craig31Kathrine R. Tan32Robert A. Wirtz33Tom Smith34Swiss Tropical and Public Health InstitutePMI VectorWorks, JHU Center for Communication ProgramsU.S. President’s Malaria Initiative, U.S. Agency for International DevelopmentDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionPMI VectorWorksDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionNational Malaria Control Program (NMCP), Ministry of HealthCentre de Recherche Entomologique de Cotonou (CREC)Centre de Recherche Entomologique de Cotonou (CREC)Kenya Medical Research Institute (KEMRI)Kenya Medical Research Institute (KEMRI)College of Medicine, Malaria Alert CentreInstituto Nacional de Saúde (INS)Instituto Nacional de Saúde (INS)Instituto Nacional de Saúde (INS)Faculté des Sciences et Techniques (FST), Université Cheikh Anta Diop (UCAD)Faculté des Sciences et Techniques (FST), Université Cheikh Anta Diop (UCAD)National Malaria Control Centre (NMCC)National Malaria Control Centre (NMCC)Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionU.S. President’s Malaria Initiative, Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionU.S. President’s Malaria Initiative, Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionDivision of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and PreventionSwiss Tropical and Public Health InstituteAbstract Background Long-lasting insecticidal nets (LLINs) are the primary malaria prevention and control intervention in many parts of sub-Saharan Africa. While LLINs are expected to last at least 3 years under normal use conditions, they can lose effectiveness because they fall out of use, are discarded, repurposed, physically damaged, or lose insecticidal activity. The contributions of these different interrelated factors to durability of nets and their protection against malaria have been unclear. Methods Starting in 2009, LLIN durability studies were conducted in seven countries in Africa over 5 years. WHO-recommended measures of attrition, LLIN use, insecticidal activity, and physical integrity were recorded for eight different net brands. These data were combined with analyses of experimental hut data on feeding inhibition and killing effects of LLINs on both susceptible and pyrethroid resistant malaria vectors to estimate the protection against malaria transmission—in terms of vectorial capacity (VC)—provided by each net cohort over time. Impact on VC was then compared in hypothetical scenarios where one durability outcome measure was set at the best possible level while keeping the others at the observed levels. Results There was more variability in decay of protection over time by country than by net brand for three measures of durability (ratios of variance components 4.6, 4.4, and 1.8 times for LLIN survival, use, and integrity, respectively). In some countries, LLIN attrition was slow, but use declined rapidly. Non-use of LLINs generally had more effect on LLIN impact on VC than did attrition, hole formation, or insecticide loss. Conclusions There is much more variation in LLIN durability among countries than among net brands. Low levels of use may have a larger impact on effectiveness than does variation in attrition or LLIN degradation. The estimated entomological effects of chemical decay are relatively small, with physical decay probably more important as a driver of attrition and non-use than as a direct cause of loss of effect. Efforts to maximize LLIN impact in operational settings should focus on increasing LLIN usage, including through improvements in LLIN physical integrity. Further research is needed to understand household decisions related to LLIN use, including the influence of net durability and the presence of other nets in the household.http://link.springer.com/article/10.1186/s12936-020-03383-6Long-lasting insecticidal netsDurability monitoringVectorial capacityMalaria |