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Insecticide-treated net use before and after mass distribution in a fishing community along Lake Victoria, Kenya: successes and unavoidable pitfalls.

Larson PS, Minakawa N, Dida GO, Njenga SM, Ionides EL, Wilson ML - Malar. J. (2014)

Bottom Line: Household factors such as availability of nets and sleeping arrangements still reduced consistent net use, however.Comprehensive, direct-to-household, mass distribution of ITNs was effective in rapidly scaling up coverage, with use being maintained at a high level at least one year following the intervention.Free distribution of ITNs through direct-to-household distribution method can eliminate important constraints in determining consistent ITN use, thus enhancing the sustainability of effective intervention campaigns.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029, USA. anfangen@umich.edu.

ABSTRACT

Background: Insecticide-treated nets (ITNs) have proven instrumental in the successful reduction of malaria incidence in holoendemic regions during the past decade. As distribution of ITNs throughout sub-Saharan Africa (SSA) is being scaled up, maintaining maximal levels of coverage will be necessary to sustain current gains. The effectiveness of mass distribution of ITNs, requires careful analysis of successes and failures if impacts are to be sustained over the long term.

Methods: Mass distribution of ITNs to a rural Kenyan community along Lake Victoria was performed in early 2011. Surveyors collected data on ITN use both before and one year following this distribution. At both times, household representatives were asked to provide a complete accounting of ITNs within the dwelling, the location of each net, and the ages and genders of each person who slept under that net the previous night. Other data on household material possessions, education levels and occupations were recorded. Information on malaria preventative factors such as ceiling nets and indoor residual spraying was noted. Basic information on malaria knowledge and health-seeking behaviours was also collected. Patterns of ITN use before and one year following net distribution were compared using spatial and multi-variable statistical methods. Associations of ITN use with various individual, household, demographic and malaria related factors were tested using logistic regression.

Results: After infancy (<1 year), ITN use sharply declined until the late teenage years then began to rise again, plateauing at 30 years of age. Males were less likely to use ITNs than females. Prior to distribution, socio-economic factors such as parental education and occupation were associated with ITN use. Following distribution, ITN use was similar across social groups. Household factors such as availability of nets and sleeping arrangements still reduced consistent net use, however.

Conclusions: Comprehensive, direct-to-household, mass distribution of ITNs was effective in rapidly scaling up coverage, with use being maintained at a high level at least one year following the intervention. Free distribution of ITNs through direct-to-household distribution method can eliminate important constraints in determining consistent ITN use, thus enhancing the sustainability of effective intervention campaigns.

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Related in: MedlinePlus

Fraction of household members who slept under an ITN the previous evening before and after mass distribution. Spatial patterns of ITN use are illustrated using inverse distance weighting interpolation.
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Fig2: Fraction of household members who slept under an ITN the previous evening before and after mass distribution. Spatial patterns of ITN use are illustrated using inverse distance weighting interpolation.

Mentions: The spatial distribution of the percentage of household members reporting ITN use the previous night differed between the two periods (Figure 2). Before distribution, use was low, though apparently slightly elevated in areas closer to water. One year following distribution, overall use increased, with some areas showing close to 100% compliance among household members. Statistical tests confirmed the presence of household-level clusters (spatial autocorrelation) of net use prior to the ITN distribution campaign. One year after ITNs were provided, spatial clustering was still evident, though to a lesser degree (Moran’s I statistic: Pre: .158, p < 0.0001, Post: .027, p = 0.0001). Knowing this, ArcGIS was used to calculate the Getis-Ord Gi* statistic, a measure of spatial clustering of high and low values within a dataset. The Gi* stat was plotted for each household, both before and after the mass distribution (see Figure 3). Prior to distribution high levels of ITN use were found in the areas close to the water on the western side of the area. Low levels of use were found inland nearby a paved road and in other parts of the area. Following distribution, clusters of extraordinarily high coverage were few, likely because most the residents of most households reported sleeping under an ITN. However, clusters of households where a significantly lower percentage of persons slept under an ITN were to be found again by the paved road and also small areas close to the water on the western side.Figure 2


Insecticide-treated net use before and after mass distribution in a fishing community along Lake Victoria, Kenya: successes and unavoidable pitfalls.

Larson PS, Minakawa N, Dida GO, Njenga SM, Ionides EL, Wilson ML - Malar. J. (2014)

Fraction of household members who slept under an ITN the previous evening before and after mass distribution. Spatial patterns of ITN use are illustrated using inverse distance weighting interpolation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4289357&req=5

Fig2: Fraction of household members who slept under an ITN the previous evening before and after mass distribution. Spatial patterns of ITN use are illustrated using inverse distance weighting interpolation.
Mentions: The spatial distribution of the percentage of household members reporting ITN use the previous night differed between the two periods (Figure 2). Before distribution, use was low, though apparently slightly elevated in areas closer to water. One year following distribution, overall use increased, with some areas showing close to 100% compliance among household members. Statistical tests confirmed the presence of household-level clusters (spatial autocorrelation) of net use prior to the ITN distribution campaign. One year after ITNs were provided, spatial clustering was still evident, though to a lesser degree (Moran’s I statistic: Pre: .158, p < 0.0001, Post: .027, p = 0.0001). Knowing this, ArcGIS was used to calculate the Getis-Ord Gi* statistic, a measure of spatial clustering of high and low values within a dataset. The Gi* stat was plotted for each household, both before and after the mass distribution (see Figure 3). Prior to distribution high levels of ITN use were found in the areas close to the water on the western side of the area. Low levels of use were found inland nearby a paved road and in other parts of the area. Following distribution, clusters of extraordinarily high coverage were few, likely because most the residents of most households reported sleeping under an ITN. However, clusters of households where a significantly lower percentage of persons slept under an ITN were to be found again by the paved road and also small areas close to the water on the western side.Figure 2

Bottom Line: Household factors such as availability of nets and sleeping arrangements still reduced consistent net use, however.Comprehensive, direct-to-household, mass distribution of ITNs was effective in rapidly scaling up coverage, with use being maintained at a high level at least one year following the intervention.Free distribution of ITNs through direct-to-household distribution method can eliminate important constraints in determining consistent ITN use, thus enhancing the sustainability of effective intervention campaigns.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029, USA. anfangen@umich.edu.

ABSTRACT

Background: Insecticide-treated nets (ITNs) have proven instrumental in the successful reduction of malaria incidence in holoendemic regions during the past decade. As distribution of ITNs throughout sub-Saharan Africa (SSA) is being scaled up, maintaining maximal levels of coverage will be necessary to sustain current gains. The effectiveness of mass distribution of ITNs, requires careful analysis of successes and failures if impacts are to be sustained over the long term.

Methods: Mass distribution of ITNs to a rural Kenyan community along Lake Victoria was performed in early 2011. Surveyors collected data on ITN use both before and one year following this distribution. At both times, household representatives were asked to provide a complete accounting of ITNs within the dwelling, the location of each net, and the ages and genders of each person who slept under that net the previous night. Other data on household material possessions, education levels and occupations were recorded. Information on malaria preventative factors such as ceiling nets and indoor residual spraying was noted. Basic information on malaria knowledge and health-seeking behaviours was also collected. Patterns of ITN use before and one year following net distribution were compared using spatial and multi-variable statistical methods. Associations of ITN use with various individual, household, demographic and malaria related factors were tested using logistic regression.

Results: After infancy (<1 year), ITN use sharply declined until the late teenage years then began to rise again, plateauing at 30 years of age. Males were less likely to use ITNs than females. Prior to distribution, socio-economic factors such as parental education and occupation were associated with ITN use. Following distribution, ITN use was similar across social groups. Household factors such as availability of nets and sleeping arrangements still reduced consistent net use, however.

Conclusions: Comprehensive, direct-to-household, mass distribution of ITNs was effective in rapidly scaling up coverage, with use being maintained at a high level at least one year following the intervention. Free distribution of ITNs through direct-to-household distribution method can eliminate important constraints in determining consistent ITN use, thus enhancing the sustainability of effective intervention campaigns.

Show MeSH
Related in: MedlinePlus