Characterization of vector communities and biting behavior in South Sulawesi with host decoy traps and human landing catches

Background: Indonesia has high mosquito diversity, with circulating malaria and arboviruses. Human landing catches (HLC) are ethically questionable where arboviral transmission occurs. The host decoy trap (HDT) is an expo- sure-free alternative outdoor sampling device. To determine HDT efcacy for local culicids, and to characterize local mosquito fauna, the trapping efcacy of the HDT was compared to that of HLCs in one peri-urban (Lakkang) and one rural (Pucak) village in Sulawesi, Indonesia.
Results: In Lakkang the outdoor HLCs collected signifcantly more Anopheles per night (n=22±9) than the HDT (n=3±1), while the HDT collected a signifcantly greater nightly average of Culex mosquitoes (n=110±42), than the outdoor HLC (n=15.1±6.0). In Pucak, there was no signifcant diference in Anopheles collected between trap types; however, the HDT collected signifcantly more Culex mosquitoes than the outdoor HLC nightly average (n=53±11 vs 14±3). Signifcantly higher proportions of blood-fed mosquitoes were found in outdoor HLC (n=15±2%) compared to HDT (n=2±0%). More blood-fed culicines were collected with outdoor HLC compared to the HDT, while Anoph- eles blood-fed proportions did not difer. For the HDT, 52.6%, 36.8% and 10.5% of identifed blood meals were on cow, human, and dog, respectively. Identifed blood meals for outdoor HLCs were 91.9% human, 6.3% cow, and 0.9% each dog and cat. Mosquitoes from Pucak were tested for arboviruses, with one Culex pool and one Armigeres pool positive for favivirus, and one Anopheles pool positive for alphavirus.
Conclusions: The HDT collected the highest abundance of culicine specimens. Outdoor HLCs collected the highest abundance of Anopheles specimens. Although the HDT can attract a range of diferent Asian mosquito genera and species, it remains to be optimized for Anopheles in Asia. The high proportion of human blood meals in mosquitoes collected by outdoor HLCs raises concerns on the potential exposure risk to collectors using this methodology and highlights the importance of continuing to optimize a host-mimic trap such as the HDT.