An observational study of material durability of three World Health Organization-recommended long-lasting insecticidal nets in eastern Chad.

A total of 876 nets (229 Interceptor(®), 363 Olyset(®), and 284 PermaNet(®)) were collected 14 months post-distribution of long-lasting insecticidal nets (LLINs) from 811 households of internally displaced and host communities in Dar Sila District in eastern Chad to examine their physical condition. Holes were recorded by using three hole categories (average diameter = 2, 3.5, and 15 cm) and a Proportionate Hole Index (pHI). A total of 69.5% were in poor or very poor condition. There was no significant difference in the performance between the polyester 75 denier LLINs, but they had 4.22 times the odds of having a pHI ≥ 175 (poor or very poor condition) than polyethylene 150 denier LLINs; and 39.2% were unserviceable (pHI ≥ 300) compared with only 7.7% of the polyethylene LLINs. These results provide the first comparative data on LLIN material durability to guide procurement and replacement practice, and to inform urgently needed changes in LLIN international minimum specifications and product standards.