Durability of Olyset campaign nets distributed between 2009 and 2011 in eight districts of Tanzania

Malaria Journal

Table 3 Number and proportion of Olyset nets of different ages with recommended permethrin content and passed WHO cone/tunnel tests criteria

Explanatory variables	Net age (months) ( %)
Explanatory variables	≤25	26–36	37–48	>48
Number of sub-sampled nets	48 (24)	106 (54)	27 (14)	17 (8)
Cone assay
Proportion of nets passed WHO cone assay criteria^a	30 (62)	64 (60)	20 (74)	12 (71)
Pass WHO cone or tunnel tests^b
Proportion of nets passed WHO cone or tunnel tests criteria	45 (94)	105 (99)	27 (100)	17 (100)
Chemical residue
Proportion of nets with recommended permethrin content	41 (85)	86 (81)	20 (74)	8 (47)
Mean permethrin content in g/kg (95 % CI)	16.8 (16.3–17.2)	16.8 (16.4–17.4)	16.5 (15.7–17.3)	14.0 (12.0–16.0)

^a WHO cone assay criteria: ≥95 % knockdown and/or ≥80 % mortality pass rate
^b WHO tunnel test criteria: ≥80 % mortality and/or ≥90 % blood feeding inhibition pass rate

ISSN: 1475-2875