Novel Insights into Malaria Vector Surveillance in Madagascar Using a Quadrant Enabled Screen Trap (QUEST) and Bloodmeal Detection Assay for Regional Transmission (BLOODART)

Abstract

31 Background: The Madagascar National Strategic Plan for Malaria Control 2018 (NSP) outlines 32 malaria control pre-elimination strategies that include detailed goals for mosquito control. 33 Primary surveillance protocols and mosquito control interventions focus on indoor vectors of 34 malaria, while many potential vectors feed and rest outdoors. Here we describe the application of 35 novel tools that advance our understanding of diversity, host choice, and Plasmodium infection 36 in the Anopheline mosquitoes of the Western Highland Fringe of Madagascar. 37 Methodology/Principal Findings: We employed a novel outdoor trap, the QUadrant Enabled 38 Screen Trap (QUEST), in conjunction with the recently developed multiplex BLOOdmeal 39 Detection Assay for Regional Transmission (BLOODART). We captured a total of 1252 female 40 Anopheles mosquitoes (10 species), all of which were subjected to BLOODART analysis. 41 QUEST collection captured a heterogenous distribution of mosquito density, diversity, host 42 choice, and Plasmodium infection. Concordance between Anopheles morphology and 43 BLOODART species identifications ranged from 93-99%. Mosquito feeding behavior in this 44 collection frequently exhibited multiple blood meal hosts (single host = 53.6%, two hosts = 45 42.1%, three hosts = 4.3%). The overall percentage of human positive bloodmeals increased 46 between the December 2017 and the April 2018 timepoints (27% to 44%). Plasmodium 47 positivity was found primarily in vectors considered to be of secondary importance, with an 48 overall prevalence of 6%.49 Conclusions/Significance: The QUEST was an efficient tool for sampling Anopheline 50 mosquitoes. Vectors considered to be of secondary importance were commonly found with 51 Plasmodium DNA in their abdomens, indicating a need to account for these species in routine 52 surveillance efforts. Mosquitoes exhibited multiple blood feeding behavior within a gonotrophic 4 53 cycle, with predominantly non-human hosts in the bloodmeal. Taken together, this complex 54 feeding behavior could enhance the role of multiple Anopheline species in malaria transmission, 55 possibly tempered by zoophilic feeding tendencies. 57 Author Summary 58Malaria continues to be a significant threat to public health in Madagascar. Elimination of 59 this disease is impeded by numerous factors, such as vector surveillance that does little to 60 account for the potential role of secondary malaria vectors, which rest and feed outdoors. In this 61 study, we designed a novel, low cost QUadrant Enabled Screen Trap (QUEST) to address the 62 lack of traps for outdoor mosquitoes. We used this in conjunction with our novel BLOOdmeal 63 Detection Assay for Regional Transmission (BLOODART) to assess mosquito feeding behavior 64 in the Western Highland Fringe of Madagascar. Our analysis revealed significant variability in 65 mosquito density, diversity, host choice, and Plasmodium infection across traps placed within 66 and between two nearby villages at two timepoints; indicating a strong, small-scale sp...

Rapid range shifts in AfricanAnophelesmosquitoes over the last century

“…New rapid diagnostics for malaria, and global efforts to integrate and bolster mosquito surveillance, will help researchers tackle these threats, as will future efforts to maintain and expand long-term datasets like the one we use here. [50–52] We recommend that focusing some of these efforts in the highlands of eastern Africa and Madagascar, and on the southern range limits of Anopheles gambiae complex, will likely be the strongest line of defense against the expansion of malaria epidemics into new populations in a changing climate.…”