Comparing the durability of the long-lasting insecticidal nets DawaPlus® 2.0 and DuraNet© in northwest Democratic Republic of Congo

Abstract

Background Anecdotal reports from DRC suggest that long-lasting insecticidal nets (LLIN) distributed through mass campaigns in DRC may not last the expected average three years. To provide the National Malaria Control Programme with evidence on physical and insecticidal durability of nets distributed during the 2016 mass campaign, two brands of LLIN, DawaPlus® 2.0 and DuraNet©, were monitored in neighbouring and similar health zones in Sud Ubangi and Mongala Provinces. Methods This was a prospective cohort study of representative samples of households from two health zones recruited at baseline, 2 months after the mass campaign. All campaign nets in these households were labelled, and followed up over a period of 31 months. Primary outcome was the “proportion of nets surviving in serviceable condition” based on attrition and integrity measures and the median survival in years. The outcome for insecticidal durability was determined by bio-assay from subsamples of campaign nets. Results A total of 754 campaign nets (109% of target) from 240 households were included in the study. Definite outcomes could be determined for 67% of the cohort nets in Sud Ubangi and 74% in Mongala. After 31 months all-cause attrition was 57% in Sud Ubangi and 76% in Mongala (p = 0.005) and attrition due to wear and tear was 26% in Sud Ubangi and 48% in Mongala (p = 0.0009). Survival in serviceable condition at the last survey was 37% in Sud Ubangi and 17% in Mongala (p = 0.003). Estimated median survival was 1.6 years for the DawaPlus® 2.0 in Mongala (95% CI 1.3–1.9) and 2.2 years for the DuraNet in Sud Ubangi (95% CI 2.0–2.4). Multivariable Cox proportionate hazard models suggest that the difference between sites was mainly attributable to the LLIN brand. Insecticidal effectiveness was optimal for DuraNet©, but significantly dropped after 24 months for DawaPlus® 2.0. Conclusions In the environment of northwest DRC the polyethylene LLIN DuraNet© performed significantly better than the polyester LLIN DawaPlus® 2.0, but both were below a three-year median survival. Improvement of net care behaviours should be able to improve physical durability.

Evaluation of the Durability of Long-Lasting Insecticidal Nets in Guatemala

“…At these time points, the main reason reported for not having a net present in the household was because it had been 'given away to others', not because of wear and tear. These ndings are similar to previous reports (Gnanguenon, Azondekon, Oke-Agbo, Beach, & Akogbeto, 2014;Mansiangi et al, 2020;Obi et al, 2020), highlighting the real-life challenges faced by national malaria programs, which reach beyond the quality of the fabric of the nets. In a large study evaluating 14 household surveys from four African countries, 34% of the nets that were not present in the household had been given away, the majority to family members and within the rst month after a distribution campaign (Koenker et al, 2014).…”

Assessment of the Durability and Bio-effectiveness of Three Long-Lasting Insecticidal Nets in Three Different Communities After the 2017 Mass Net Distribution Campaign in Benin

“…This result, similar to that obtained in India for the same brand of LLIN (74.8 after 30 months) is much higher than the 50.9% survival of PermaNet®2.0 in our study (Sudhansu Sekhar Sahu, et al, 2020). On the other hand, another study carried out in Congo, still published in 2020 and which compared DuraNet® to DawaPlus®2.0 found a survival of 33.2% for the LLIN DawaPlus®2.0 after 2 years, a result similar to our for the same type of LLIN after 2 years of follow-up (38.2%) (Mansiangi, P, et al, 2020).…”

“…Benin, compared to this objective is not late because 80% of households have a LLIN for two people (MIS, 2017). However, the importance of the durability of nets and the "average useful life" of a net is increasingly recognized as critical factors in the design of malaria control programs, as these determine the how often should the nets be replaced and what type of mosquito net to purchase (Azondekon R, et al, 2014;Gnanguenon V, et al, 2014;Hakizimana E, et al, 2014;Mansiangi P, et al, 2020). This is reflected in the WHO guidelines for monitoring LLINs in the field, which recommends that countries regularly monitor the durability of the nets.…”

The fabric of life: what if mosquito nets were durable and widely available but insecticide-free?

“…Field evidence increasingly shows that current ITNs do not last as long as expected under real use settings, and that there is a wide variation in both bio-efficacy and durability in different settings [181][182][183][184]. In one study in Tanzania, scientists examined the durability of ITNs distributed by the government between 2009 and 2011 in eight districts [185].…”