Limits...
Physical durability of PermaNet 2.0 long-lasting insecticidal nets over three to 32 months of use in Ethiopia.

Wills AB, Smith SC, Anshebo GY, Graves PM, Endeshaw T, Shargie EB, Damte M, Gebre T, Mosher AW, Patterson AE, Tesema YB, Richards FO, Emerson PM - Malar. J. (2013)

Bottom Line: Holes continued to accumulate until 92.5% of nets had holes by 26 to 32 months of use.An almost complete lack of repairs shows the need for promoting proper use of nets and repairs, to increase LLIN longevity.Using the hole index, almost one third of the nets were classed as unusable and ineffective after two and a half years of potential use.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Ethiopia scaled up net distribution markedly starting in 2006. Information on expected net life under field conditions (physical durability and persistence of insecticidal activity) is needed to improve planning for net replacement. Standardization of physical durability assessment methods is lacking.

Methods: Permanet®2.0 long-lasting insecticidal bed nets (LLINs), available for distribution in early 2007, were collected from households at three time intervals. The number, size and location of holes were recorded for 189 nets used for three to six months from nine sites (2007) and 220 nets used for 14 to 20 months from 11 sites (2008). In 2009, a "finger/fist" sizing method classified holes in 200 nets used for 26 to 32 months from ten sites into small (<2 cm), medium (> = 2 to < =10 cm) and large (>10 cm) sizes. A proportionate hole index based on both hole number and area was derived from these size classifications.

Results: After three to six months, 54.5% (95% CI 47.1-61.7%) of 189 LLINs had at least one hole 0.5 cm (in the longest axis) or larger; mean holes per net was 4.4 (SD 8.4), median was 1.0 (Inter Quartile Range [IQR] 0-5) and median size was 1 cm (IQR 1-2). At 14 to 20 months, 85.5% (95% CI 80.1-89.8%) of 220 nets had at least one hole with mean 29.1 (SD 50.1) and median 12 (IQR 3-36.5) holes per net, and median size of 1 cm (IQR 1-2). At 26 to 32 months, 92.5% of 200 nets had at least one hole with a mean of 62.2 (SD 205.4) and median of 23 (IQR 6-55.5) holes per net. The mean hole index was 24.3, 169.1 and 352.8 at the three time periods respectively. Repairs were rarely observed. The majority of holes were in the lower half of the net walls. The proportion of nets in 'poor' condition (hole index >300) increased from 0% at three to six months to 30% at 26 to 32 months.

Conclusions: Net damage began quickly: more than half the nets had holes by three to six months of use, with 40% of holes being larger than 2 cm. Holes continued to accumulate until 92.5% of nets had holes by 26 to 32 months of use. An almost complete lack of repairs shows the need for promoting proper use of nets and repairs, to increase LLIN longevity. Using the hole index, almost one third of the nets were classed as unusable and ineffective after two and a half years of potential use.

Show MeSH

Related in: MedlinePlus

Percentage of holes in each size category, by time group of collection.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3733833&req=5

Figure 5: Percentage of holes in each size category, by time group of collection.

Mentions: Although there were more nets with holes as the time periods progressed, and the number of medium and large holes increased (Table 3), the relative number of holes of different sizes (small <2 cm; medium > =2 and < =10 cm; large >10 cm) did not change between the time periods of collection (Figure 5).


Physical durability of PermaNet 2.0 long-lasting insecticidal nets over three to 32 months of use in Ethiopia.

Wills AB, Smith SC, Anshebo GY, Graves PM, Endeshaw T, Shargie EB, Damte M, Gebre T, Mosher AW, Patterson AE, Tesema YB, Richards FO, Emerson PM - Malar. J. (2013)

Percentage of holes in each size category, by time group of collection.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3733833&req=5

Figure 5: Percentage of holes in each size category, by time group of collection.
Mentions: Although there were more nets with holes as the time periods progressed, and the number of medium and large holes increased (Table 3), the relative number of holes of different sizes (small <2 cm; medium > =2 and < =10 cm; large >10 cm) did not change between the time periods of collection (Figure 5).

Bottom Line: Holes continued to accumulate until 92.5% of nets had holes by 26 to 32 months of use.An almost complete lack of repairs shows the need for promoting proper use of nets and repairs, to increase LLIN longevity.Using the hole index, almost one third of the nets were classed as unusable and ineffective after two and a half years of potential use.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Ethiopia scaled up net distribution markedly starting in 2006. Information on expected net life under field conditions (physical durability and persistence of insecticidal activity) is needed to improve planning for net replacement. Standardization of physical durability assessment methods is lacking.

Methods: Permanet®2.0 long-lasting insecticidal bed nets (LLINs), available for distribution in early 2007, were collected from households at three time intervals. The number, size and location of holes were recorded for 189 nets used for three to six months from nine sites (2007) and 220 nets used for 14 to 20 months from 11 sites (2008). In 2009, a "finger/fist" sizing method classified holes in 200 nets used for 26 to 32 months from ten sites into small (<2 cm), medium (> = 2 to < =10 cm) and large (>10 cm) sizes. A proportionate hole index based on both hole number and area was derived from these size classifications.

Results: After three to six months, 54.5% (95% CI 47.1-61.7%) of 189 LLINs had at least one hole 0.5 cm (in the longest axis) or larger; mean holes per net was 4.4 (SD 8.4), median was 1.0 (Inter Quartile Range [IQR] 0-5) and median size was 1 cm (IQR 1-2). At 14 to 20 months, 85.5% (95% CI 80.1-89.8%) of 220 nets had at least one hole with mean 29.1 (SD 50.1) and median 12 (IQR 3-36.5) holes per net, and median size of 1 cm (IQR 1-2). At 26 to 32 months, 92.5% of 200 nets had at least one hole with a mean of 62.2 (SD 205.4) and median of 23 (IQR 6-55.5) holes per net. The mean hole index was 24.3, 169.1 and 352.8 at the three time periods respectively. Repairs were rarely observed. The majority of holes were in the lower half of the net walls. The proportion of nets in 'poor' condition (hole index >300) increased from 0% at three to six months to 30% at 26 to 32 months.

Conclusions: Net damage began quickly: more than half the nets had holes by three to six months of use, with 40% of holes being larger than 2 cm. Holes continued to accumulate until 92.5% of nets had holes by 26 to 32 months of use. An almost complete lack of repairs shows the need for promoting proper use of nets and repairs, to increase LLIN longevity. Using the hole index, almost one third of the nets were classed as unusable and ineffective after two and a half years of potential use.

Show MeSH
Related in: MedlinePlus