Follow-up for ITN fabric integrity
Fabric integrity (hole index) and condition will be observed on all nets of cohort 1 at 6-, 12-, 24- and 36-months post distribution. Where the minimum number (250) of nets for fabric integrity is not attainable from the longitudinal cohort (cohort 1) due to loss, ITNs sampled destructively from the same clusters for bio-efficacy would first be examined for fabric integrity prior to the bio-efficacy studies. The survey team will inspect the nets outside in broad day light to determine the hole index using a portable frame over which the net can be draped during inspection. The nets will be returned to the family right after the inspection. Hole number, position and size will be assessed on each ITN panel (roof and sides) using hole assessment sheets and classified into 4 sizes (size 1: 0.5-2 cm, Size 2: 2–10 cm, Size 3: 10-25 cm, and size 4: > 25 cm). Physical integrity will be measured as the proportionate hole index (pHI), categorized based on recommended cut-off points into “good” condition (pHI 0–64), “acceptable” condition (pHI 65–642) and “torn” (pHI 643 +) defined in WHO guidelines [