Evaluation of Mosquito Magnet and other collection tools for Anopheles mosquito vectors of simian malaria

Abstract

Background Vector surveillance is essential in determining the geographical distribution of mosquito vectors and understanding the dynamics of malaria transmission. With the elimination of human malaria cases, knowlesi malaria cases in humans are increasing in Malaysia. This necessitates intensive vector studies using safer trapping methods which are both field efficient and able to attract the local vector populations. Thus, this study evaluated the potential of Mosquito Magnet as a collection tool for Anopheles mosquito vectors of simian malaria along with other known collection methods. Methods A randomized 4 × 4 Latin square designed experiment was conducted to compare the efficiency of the Mosquito Magnet against three other common trapping methods: human landing catch (HLC), CDC light trap and human baited trap (HBT). The experiment was conducted over six replicates where sampling within each replicate was carried out for 4 consecutive nights. An additional 4 nights of sampling was used to further evaluate the Mosquito Magnet against the “gold standard” HLC. The abundance of Anopheles sampled by different methods was compared and evaluated with focus on the Anopheles from the Leucosphyrus group, the vectors of knowlesi malaria. Results The Latin square designed experiment showed HLC caught the greatest number of Anopheles mosquitoes (n = 321) compared to the HBT (n = 87), Mosquito Magnet (n = 58) and CDC light trap (n = 13). The GLMM analysis showed that the HLC method caught significantly more Anopheles mosquitoes compared to Mosquito Magnet (P = 0.049). However, there was no significant difference in mean nightly catch of Anopheles mosquitoes between Mosquito Magnet and the other two trapping methods, HBT (P = 0.646) and CDC light traps (P = 0.197). The mean nightly catch for both An. introlatus (9.33 ± 4.341) and An. cracens (4.00 ± 2.273) caught using HLC was higher than that of Mosquito Magnet, though the differences were not statistically significant (P > 0.05). This is in contrast to the mean nightly catch of An. sinensis (15.75 ± 5.640) and An. maculatus (15.78 ± 3.479) where HLC showed significantly more mosquito catches compared to Mosquito Magnet (P < 0.05). Conclusions Mosquito Magnet has a promising ability to catch An. introlatus and An. cracens, the important vectors of knowlesi and other simian malarias in Peninsular Malaysia. The ability of Mosquito Magnet to catch some of the Anopheles mosquito species is comparable to HLC and makes it an ethical and safer alternative. Graphic Abstract

Multiplex PCR Assay for the Identification of Four Species of the Anopheles Leucosphyrus Sub-Group in Malaysia

“…latens clade II [46] used in the study were collected from different states in Malaysia, namely Johor, Kelantan, Pahang, Selangor, Sabah, and Sarawak, where most simian malaria infections were reported [47] (Figure 1) (Table S1). Mosquitoes were collected using bare-leg capture (BLC) [48] as well as human baited trap, CDC light trap, and mosquito magnet from 18:00 to 23:30 as described in the work of [49]. The Anopheles mosquitoes were morphologically identified using the keys of Reid [50] and Sallum [18].…”

Blood meal analysis of Anopheles vectors of simian malaria based on laboratory and field studies

“…In view of this, a series of laboratory tests was conducted to validate the use of mosquitoes caught using HLC for blood meal analysis. This is mainly because HLC was able to catch a higher number of local Anopheles mosquitoes, besides Mosquito Magnet 17 . Thus, this is the first study to evaluate the use of Anopheles mosquitoes collected through HLC for blood meal analysis.…”

“…The presence of domestic and wild animals at each sampling locations were observed and recorded. Vector collections were carried out using human landing catch and Mosquito Magnet (Model: Independence; Manufacturer: Woodstream Corp., USA) 17 . One Mosquito Magnet was used in this study.…”

“…The collected Anopheles mosquitoes were morphologically identified to the species level by using the taxonomic keys of Reid 37 and Sallum 52 . However, for Anopheles mosquitoes from the Leucosphyrus Group and mosquitoes which were not able to be identified morphologically, the species were molecularly confirmed through DNA sequencing of the PCR amplified ITS2 gene using ITS2A and ITS2B primers 53 with protocol from the previous study 17 .…”

“…Unfortunately, out of thousands of mosquitoes collected, only a single resting Anopheles mosquito was successfully obtained from each study. Other methods available to collect non-resting mosquitoes for blood meal analysis such as CDC light traps are inefficient at collecting Anopheles mosquitoes from the Leucosphyrus Group compared to human landing catch (HLC) 16 , 17 .…”