Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua
Abstract Background A cluster-randomized controlled trial of community mobilisation for dengue prevention in Mexico and Nicaragua reported, as a secondary finding, a higher risk of dengue virus infection in households where inspectors found temephos in water containers. Data from control sites in th...
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| Format: | Article |
| Language: | English |
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BMC
2017-05-01
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| Series: | BMC Public Health |
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| Online Access: | http://link.springer.com/article/10.1186/s12889-017-4296-6 |
| _version_ | 1811328482109554688 |
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| author | Jorge Arosteguí Josefina Coloma Carlos Hernández-Alvarez Harold Suazo-Laguna Angel Balmaseda Eva Harris Neil Andersson Robert J Ledogar |
| author_facet | Jorge Arosteguí Josefina Coloma Carlos Hernández-Alvarez Harold Suazo-Laguna Angel Balmaseda Eva Harris Neil Andersson Robert J Ledogar |
| author_sort | Jorge Arosteguí |
| collection | DOAJ |
| description | Abstract Background A cluster-randomized controlled trial of community mobilisation for dengue prevention in Mexico and Nicaragua reported, as a secondary finding, a higher risk of dengue virus infection in households where inspectors found temephos in water containers. Data from control sites in the preceding pilot study and the Nicaragua trial arm provided six time points (2005, 2006, 2007 and 2011, 2012, 2013) to examine potentially protective effects of temephos on entomological indices under every day conditions of the national vector control programme. Methods Three household entomological indicators for Aedes aegypti breeding were Household Index, Households with pupae, and Pupae per Person. The primary exposure indicator at the six time points was temephos identified physically during the entomological inspection. A stricter criterion for exposure at four time points included households reporting temephos application during the last 30 days and temephos found on inspection. Using generalized linear mixed modelling with cluster as a random effect and temephos as a potential fixed effect, at each time point we examined possible determinants of lower entomological indicators. Results Between 2005 and 2013, temephos exposure was not significantly associated with a reduction in any of the three entomological indices, whether or not the exposure indicator included timing of temephos application. In six of 18 multivariate models at the six time points, temephos exposure was associated with higher entomological indices; in these models, we could exclude any protective effect of temephos with 95% confidence. Conclusion Our failure to demonstrate a significant protective association between temephos and entomological indices might be explained by several factors. These include ecological adaptability of the vector, resistance of Aedes to the pesticide, operational deficiencies of vector control programme, or a decrease in preventive actions by households resulting from a false sense of protection fostered by the centralized government programme using chemical agents. Whatever the explanation, the implication is that temephos affords less protection under routine field conditions than expected from its efficacy under experimental conditions. Trial registration ISRCTN 27581154 . |
| first_indexed | 2024-04-13T15:25:53Z |
| format | Article |
| id | doaj.art-b6cbcdfe852b476d88a38aef59269388 |
| institution | Directory Open Access Journal |
| issn | 1471-2458 |
| language | English |
| last_indexed | 2024-04-13T15:25:53Z |
| publishDate | 2017-05-01 |
| publisher | BMC |
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| series | BMC Public Health |
| spelling | doaj.art-b6cbcdfe852b476d88a38aef592693882022-12-22T02:41:30ZengBMCBMC Public Health1471-24582017-05-0117S1859210.1186/s12889-017-4296-6Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, NicaraguaJorge Arosteguí0Josefina Coloma1Carlos Hernández-Alvarez2Harold Suazo-Laguna3Angel Balmaseda4Eva Harris5Neil Andersson6Robert J Ledogar7CIET InternationalDivision of Infectious Diseases and Vaccinology, School of Public Health, University of CaliforniaCIET InternationalCIET InternationalCentro Nacional de Diagnóstico y Referencia, Ministerio de SaludDivision of Infectious Diseases and Vaccinology, School of Public Health, University of CaliforniaCentro de Investigación de Enfermedades Tropicales, Universidad Autónoma de GuerreroCIET InternationalAbstract Background A cluster-randomized controlled trial of community mobilisation for dengue prevention in Mexico and Nicaragua reported, as a secondary finding, a higher risk of dengue virus infection in households where inspectors found temephos in water containers. Data from control sites in the preceding pilot study and the Nicaragua trial arm provided six time points (2005, 2006, 2007 and 2011, 2012, 2013) to examine potentially protective effects of temephos on entomological indices under every day conditions of the national vector control programme. Methods Three household entomological indicators for Aedes aegypti breeding were Household Index, Households with pupae, and Pupae per Person. The primary exposure indicator at the six time points was temephos identified physically during the entomological inspection. A stricter criterion for exposure at four time points included households reporting temephos application during the last 30 days and temephos found on inspection. Using generalized linear mixed modelling with cluster as a random effect and temephos as a potential fixed effect, at each time point we examined possible determinants of lower entomological indicators. Results Between 2005 and 2013, temephos exposure was not significantly associated with a reduction in any of the three entomological indices, whether or not the exposure indicator included timing of temephos application. In six of 18 multivariate models at the six time points, temephos exposure was associated with higher entomological indices; in these models, we could exclude any protective effect of temephos with 95% confidence. Conclusion Our failure to demonstrate a significant protective association between temephos and entomological indices might be explained by several factors. These include ecological adaptability of the vector, resistance of Aedes to the pesticide, operational deficiencies of vector control programme, or a decrease in preventive actions by households resulting from a false sense of protection fostered by the centralized government programme using chemical agents. Whatever the explanation, the implication is that temephos affords less protection under routine field conditions than expected from its efficacy under experimental conditions. Trial registration ISRCTN 27581154 .http://link.springer.com/article/10.1186/s12889-017-4296-6TemephosClustersAedes aegyptiCamino VerdeDengue prevention |
| spellingShingle | Jorge Arosteguí Josefina Coloma Carlos Hernández-Alvarez Harold Suazo-Laguna Angel Balmaseda Eva Harris Neil Andersson Robert J Ledogar Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua BMC Public Health Temephos Clusters Aedes aegypti Camino Verde Dengue prevention |
| title | Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua |
| title_full | Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua |
| title_fullStr | Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua |
| title_full_unstemmed | Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua |
| title_short | Beyond efficacy in water containers: Temephos and household entomological indices in six studies between 2005 and 2013 in Managua, Nicaragua |
| title_sort | beyond efficacy in water containers temephos and household entomological indices in six studies between 2005 and 2013 in managua nicaragua |
| topic | Temephos Clusters Aedes aegypti Camino Verde Dengue prevention |
| url | http://link.springer.com/article/10.1186/s12889-017-4296-6 |
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