An elusive endosymbiont: DoesWolbachiaoccur naturally inAedes aegypti?

AbstractWolbachiaare maternally-inherited endosymbiotic bacteria found within many insect species.Aedesmosquitoes experimentally infected withWolbachiaare being released into the field forAedes-borne disease control. TheseWolbachiainfections 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-occurringWolbachiain target populations could interfere with both population replacement and suppression programs depending on the compatibility patterns between strains.Aedes aegyptiwere thought to not harborWolbachianaturally but several recent studies have detectedWolbachiain natural populations of this mosquito. We therefore review the evidence for naturalWolbachiainfections inAe. aegyptito date and discuss limitations of these studies. We draw on research from other mosquito species to outline the potential implications of naturalWolbachiainfections inAe. aegyptifor disease control. To validate previous reports, we obtained a laboratory population ofAe. aegyptifrom New Mexico, USA, that harbors a naturalWolbachiainfection, and we conducted field surveys in Kuala Lumpur, Malaysia where a naturalWolbachiainfection has also been reported. However, we were unable to detectWolbachiainfection in both the laboratory and field populations. Because the presence of naturally-occurringWolbachiainAe. aegypticould have profound implications forWolbachia-based disease control programs, it is important to continue to accurately assess theWolbachiastatus of targetAedespopulations.