https://www.researchsquare.com/article/rs-1236441/v1

This repository contains the bibliography.rtf file with the included studies used for synthesis. The `Effect Calculation'.r file contains all the code used to calculate the treatment effects. HLCs were considered to be group 2 for effect size calculations. Some information was extracted using the MetaDigitise library, but that code is omitted due to the nature of the how the library is used. The Analysis.r file contains all relevant statistical analysis performed. Further details about the project can be found in the paper, which will be linked here in the README after publication. The abstract is presented below for convenience.

Human landing catches (HLC) are an entomological collection technique in which humans are used as attractants to capture medically relevant host-seeking mosquitoes. This method is considered to be the gold standard in malaria vector surveillance. Despite the high-resolution data on biting time and location obtained from HLC, the use of this method has been a topic of extensive debate for decades mainly due to ethical concerns. Many alternatives to HLC have been proposed; however, to date, no quantitative review of studies comparing HLC to alternative trapping methods has been conducted. Here, we present a meta-analysis of published literature on HLC and alternative trapping methods for outdoor Anopheles spp. collections.

We identified 20 studies across 12 countries and were able to include a total of 58 comparisons. We conducted a meta-analysis comparing treatment effects of HLC against alternative traps for each study (Hedges’ g). Negative effect sizes indicate the alternative traps performed better than HLC. The initial results showed no significant difference between HLC and alternative traps but indicated substantial heterogeneity. To explain heterogeneity, moderator analysis was used. Three moderators were chosen: trap type, location of study, and species captured.

According to our model, tent-based alternative traps captured significantly more Anopheles mosquitoes than outdoor HLC (95% CI: [-.9065, -.0544]). Alternative traps evaluated in Africa captured more mosquitoes than outdoor HLC ([-2.8750, -.0294]) and alternative traps overall captured significantly more Anopheles gambiae s.l. when compared to outdoor HLC ([-4.4613, -.2473]). A meta-regression showed that up to 55.77% of the total heterogeneity found can be explained by a linear combination of the three moderators included in our model and the interaction between trap type and species collected. Subset analysis on An. gambiae s.l. showed that outdoor light traps specifically captured more of this species than outdoor HLC ([-18.3751, -1.0629]). No significant associations were found between collection method and capture of Anopheles funestus s.l.

While we found evidence that alternative traps captured more An. gambiae than did HLC, we found no differences for capture of An. funestus s.l. Publication bias was also found to be a contributing factor in the analysis with an overrepresentation in the literature of results indicating that alternative traps are superior to HLC. Additionally, trap comparisons in the literature most commonly use the total number of Anopheles collected/night as a metric for comparison, which may not be the optimal. Taken together, these results identify some trends in the literature which can be used to identify Anopheles collection alternatives to HLC. However, the significant heterogeneity suggests a broader challenge with the literature. Additionally, trap comparisons in the literature most commonly use the total number of Anopheles collected/night as a metric for comparison, which may not be the optimal. These limitations indicate the need for further standardization and more specific question-driven trap evaluations that consider factors such as target vector species and the vector control landscape. These approaches will allow for robust meta-analyses in the future with less heterogeneity and data-driven decision-making tools for malaria vector surveillance and control.

Anopheles, collection, HLC, meta-analysis, mosquito