What question did this study set out to answer?

The study aims to evaluate the bioefficacy and physical integrity of LLINs after mass distribution campaigns in Cameroon.

February 2, 2026Open Access

Reduced bioefficacy of used LLINs against natural populations of Anopheles gambiae sensu lato in the centre and east regions of Cameroon

Puntos clave

The study aims to evaluate the bioefficacy and physical integrity of LLINs after mass distribution campaigns in Cameroon.
Conducted household surveys to assess ITN ownership and usage patterns.
Measured net condition using the proportionate hole index (pHI).
Conducted WHO cone bioassays to evaluate bio-efficacy against Anopheles gambiae.
Sampled 55 LLINs from Bertoua and 30 from Eyang.
LLIN ownership was similar in both sites with 66.7% in Bertoua and 67.9% in Eyang.
Bertoua reported a higher usage rate of 73.3% compared to 58.2% in Eyang.
Bertoua's Olyset Plus nets showed a 94.6% mortality rate against the Kisumu strain, surpassing the WHO threshold.
Eyang's nets had a 79.3% mortality rate against the Kisumu strain, below the optimal threshold.
Olyset Plus showed a mortality rate of 31.8% against local field mosquitoes, higher than other brands.

Resumen

Abstract Background Long-lasting insecticidal nets (LLINs) are crucial for malaria prevention in Cameroon, yet their operational performance may be compromised because of deterioration of the physical integrity and bioefficacy of nets. This study evaluated LLINs, physical integrity, and bioefficacy following mass distribution campaigns in two regions in Cameroon: East (Bertoua) and Centre (Eyang). Methods Household surveys were conducted to assess ITN ownership, usage patterns, and maintenance practices. Net condition was measured using the proportionate hole index (pHI), and bio-efficacy was assessed using WHO cone bioassays against Anopheles gambiae (s.s.) (Kisumu strain) and local field mosquitoes. Results A total of 55 LLINs from Bertoua and 30 from Eyang were sampled. LLIN ownership was comparable between sites (66.7% in Bertoua vs. 67.9% in Eyang), with a higher usage rate in Bertoua (73.3%) compared to 58.2% in Eyang. In Bertoua, a large percentage of LLINs (59.6%) were too torn, with Olyset Plus being the most common brand. In contrast, Eyang had a lower proportion of torn nets (44%), and households used a combination of different brands, including the Olyset net, Permanet 2.0, and Royal Sentry. Against the susceptible Kisumu strain, Bertoua’s Olyset Plus nets showed optimal efficacy with a 94.6% mortality rate, exceeding the World Health Organization's (WHO) threshold of ≥ 80%. In contrast, nets from Eyang had a 79.3% mortality rate, falling short of the optimal threshold. However, when tested against local field mosquitoes, Olyset Plus (pyrethroid + PBO) showed higher efficacy (mortality rate of 31.8%) than the other brands (7.1% from Olyset net; 18.6% for Permanet 2.0; and 8.6% for Royal Sentry) ( p > 0.0001). Conclusions These findings underscore the crucial importance of proper LLINs maintenance, particularly regarding washing practices. The results also indicate the need to deploy newer generation LLINs to address emerging insecticide resistance and strengthen malaria control efforts. Graphical Abstract

Leer artículo completoexternamente

Preguntar a la IA

Me gusta

Guardar

Ver artículo completo