An elusive endosymbiont: Does Wolbachia occur naturally in Aedes aegypti?

Perran A Ross,Moshe Jasper,Ashley G Callahan,Ahmad Noor Afizah,Wasi A Nazni,Ary A Hoffmann,Mohd A K Arif,Qiong Yang

doi:10.1002/ece3.6012

Perran A Ross, Moshe Jasper + Show 6 more

Open Access

https://doi.org/10.1002/ece3.6012

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Abstract

Wolbachia are maternally inherited endosymbiotic bacteria found within many insect species. Aedes mosquitoes experimentally infected with Wolbachia are being released into the field for Aedes‐borne disease control. These Wolbachia infections induce cytoplasmic incompatibility which is used to suppress populations through incompatible matings or replace populations through the reproductive advantage provided by this mechanism. However, the presence of naturally occurring Wolbachia in target populations could interfere with both population replacement and suppression programs depending on the compatibility patterns between strains. Aedes aegypti were thought to not harbor Wolbachia naturally but several recent studies have detected Wolbachia in natural populations of this mosquito. We therefore review the evidence for natural Wolbachia infections in A. aegypti to date and discuss limitations of these studies. We draw on research from other mosquito species to outline the potential implications of natural Wolbachia infections in A. aegypti for disease control. To validate previous reports, we obtained a laboratory population of A. aegypti from New Mexico, USA, that harbors a natural Wolbachia infection, and we conducted field surveys in Kuala Lumpur, Malaysia, where a natural Wolbachia infection has also been reported. However, we were unable to detect Wolbachia in both the laboratory and field populations. Because the presence of naturally occurring Wolbachia in A. aegypti could have profound implications for Wolbachia‐based disease control programs, it is important to continue to accurately assess the Wolbachia status of target Aedes populations.

Highlights

The presence of natural Wolbachia infections in mosquitoes may interfere with disease control programs, making population replacement or suppression challenging or even impossible
The most comprehensive survey to date found no evidence for Wolbachia infection in A. aegypti through PCR assays on pools of mosquitoes, except in a single location where the experimentally generated wMel strain of Wolbachia had been released deliberately (Gloria-Soria, Chiodo, & Powell, 2018)
With most novel infections generated in A. aegypti, the release of Wolbachia-infected mosquitoes into an uninfected population will lead to cytoplasmic incompatibility (Figure 1a)

Summary

Introduction

The presence of natural Wolbachia infections in mosquitoes may interfere with disease control programs, making population replacement or suppression challenging or even impossible. The most comprehensive survey to date found no evidence for Wolbachia infection in A. aegypti through PCR assays on pools of mosquitoes, except in a single location where the experimentally generated wMel strain of Wolbachia had been released deliberately (Gloria-Soria, Chiodo, & Powell, 2018). With most novel infections generated in A. aegypti, the release of Wolbachia-infected mosquitoes into an uninfected population will lead to cytoplasmic incompatibility (Figure 1a).

Results

Conclusion