Microclimate and the vertical stratification of potential bridge vectors of mosquito\u2011borne viruses captured by nets and ovitraps in a central Amazonian forest bordering Manaus, Brazil

Adam Hendy,Nelson Ferreira Fé,Danielle Valério,Igor Pedrosa,Nikos Vasilakis,José Tenaçol Andes Júnior,Claudia Mendonça,Vera Margarete Scarpassa,Michaela Buenemann,Bárbara Aparecida Chaves,Eloane Andrade,Eduardo Hernandez-Acosta,Marcus Vinícius Guimarães De Lacerda,Marcelo Gordo,Flamarion Prado Assunção,Kathryn A Hanley,Edson Rodrigues Costa

doi:10.1038/s41598-021-00514-0

Abstract

In the Americas, some mosquito-borne viruses such as Zika, chikungunya, and dengue circulate among humans in urban transmission cycles, while others, including yellow fever and Mayaro, circulate among monkeys in sylvatic cycles. The intersection of humans and wildlife at forest edges creates risk for zoonotic virus exchange. We built a scaffold tower at the edge of a treefall gap in rainforest bordering Manaus, Brazil, to identify vectors that may bridge transmission between humans and monkeys. We vertically sampled diurnally active, anthropophilic mosquitoes using handheld nets at 0, 5, and 9 m and container-breeding mosquitoes in ovitraps at 0, 5, 10, and 15 m. Haemagogus janthinomys and Psorophora amazonica were present in high relative abundance in nets at each height sampled, while anthropophilic species were uncommon in ovitraps. Hg. janthinomys was more abundant at elevated heights than at ground level, while Ps. amazonica abundance was not significantly stratified across heights. The presence of each species increased with increasing 7-day rainfall lagged at 1 week, and at 1 and 4 weeks prior to collection, respectively. In addition, Hg. janthinomys was most frequently collected at 29.9 °C, irrespective of height. These data provide insight into the potential role of each species as bridge vectors.

Highlights

In the Americas, some mosquito-borne viruses such as Zika, chikungunya, and dengue circulate among humans in urban transmission cycles, while others, including yellow fever and Mayaro, circulate among monkeys in sylvatic cycles
Which mosquito species effectively bridge urban and sylvatic cycles is determined in part by their vertical stratification relative to humans living at ground level and sylvatic hosts which may prefer different heights within the forest canopy
We recently identified Haemagogus janthinomys, Sabethes chloropterus, and Psorophora amazonica as potential bridge vectors of mosquito-borne arboviruses in a rainforest reserve bordering the city of Manaus, B razil[15]

Summary

Introduction

In the Americas, some mosquito-borne viruses such as Zika, chikungunya, and dengue circulate among humans in urban transmission cycles, while others, including yellow fever and Mayaro, circulate among monkeys in sylvatic cycles. We recently identified Haemagogus janthinomys, Sabethes chloropterus, and Psorophora amazonica as potential bridge vectors of mosquito-borne arboviruses in a rainforest reserve bordering the city of Manaus, B razil[15]. Analyses of relationships between microclimate and the occurrence of Haemagogus and Sabethes mosquitoes showed that detection of both genera significantly increased with increasing temperature and decreasing relative humidity at several heights s ampled[15] These findings support anecdotal evidence that Hg. janthinomys[18] and other acrodendrophilic species[16] increase in abundance at ground level at forest edges, where high temperatures and low humidity create conditions similar to those found in the forest canopy[5,15]

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Results

Conclusion