*2.1. Study Area*

Bioassays were performed at the Vector Control Product Testing Unit (VCPTU) facility located at the Bagamoyo branch of Ifakara Health Institute (IHI), Tanzania (6.446◦ S and 38.901◦ E).

#### *2.2. Description of Investigational ITNs*

Interceptor® is made from 100-denier polyester coated with 200 mg/m<sup>2</sup> alphacypermethrin and Interceptor® G2 is made of 100-denier polyester coated with a mixture of 200 mg/m<sup>2</sup> chlorfenapyr and 100 mg/m<sup>2</sup> alpha-cypermethrin. Both net brands are manufactured by BASF, Germany. Safi Net, made of polyester manufactured by A to Z Textile Mills, Tanzania, was used as a negative control to monitor the quality of the bioassay. The study included the following arms: (1) unwashed Interceptor®; (2) Interceptor® washed 20 times; (3) unwashed Interceptor® G2; (4) Interceptor® G2 washed 20 times; (5) negative control–Safi Net. Five samples per net were cut and samples were washed twenty times according to a protocol adapted from the standard WHO washing procedure [20] using 20 g/L palm soap (Jamaa brand). The interval of time used between two washes (i.e., regeneration time) was 1 day for both Interceptor® G2 and Interceptor® ITNs (Table 1).


#### **Table 1.** Experimental design.
