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RESEARCH: Ifakara scientist develops new method for testing new generation of anti-malaria bed nets

June 14, 2022
RESEARCH: Ifakara scientist develops new method for testing new generation of anti-malaria bed nets
A snip from the BMC Parasites & Vectors journal with an inset of Ifakara Health Institute researcher, Ms. Ummi Kibondo, who developed the new bioassay. GRAPHIC |IFAKARA/Coms.

Ifakara Health Institute scientist, Ummi Kibondo (inset), has developed a new bioassay (method) for testing a new generation of treated bed nets proven to reduce malaria in areas known to have insecticide resistance in Tanzania.

Ms. Kibondo and colleagues from the Ifakara’s Vector Control Product Testing Unit (VCPTU) have developed the bioassay technically named “Ifakara Ambient Chamber Test” – simply abbreviated “I-ACT” – for evaluating “Interceptor® G2” bed nets.

Interceptor® G2 is the new generation of bed-net developed for insecticide resistance management that contains two insecticides: alpha-cypermethrin (pyrethroid) and chlorfenapyr that is a pro-insecticide and therefore mosquitoes need to be metabolically active during bioefficacy assessment.

Now, how the performance of Interceptor® G2 was evaluated? Mosquito exposures to pyrethroid only Interceptor® and pyrethroid/chlorfenapyr Interceptor® G2 was done in laboratory and experimental hut bioassay tests. The new I-ACT laboratory bioassay was compared to standard WHO laboratory bioassays, WHO cone and WHO tunnel tests, and the gold standard experimental hut study that was conducted in Lupiro village in Ulanga District, south-eastern Tanzania.

The study observed that the I-ACT measured similarly to the WHO tunnel test that is currently recommended for evaluation of chlorfenapyr bed-nets, and both laboratory assays predicted the results of experimental hut tests.

In this setting, I-ACT was a reliable bioassay for bio-efficacy testing of Interceptor® G2 and maybe a useful additional bioassay for durability monitoring of bed nets treated with pro-insecticides to measure the biological durability of these nets.

For more detail regarding this work, click here.