WolbachiastrainwAlbB maintains high density and dengue inhibition following introduction into a field population ofAedes aegypti

Abstract

Aedes aegypti mosquitoes carrying the w AlbB Wolbachia strain show a reduced capacity to transmit dengue virus. w AlbB has been introduced into wild Ae. aegypti populations in several field sites in Kuala Lumpur, Malaysia, where it has persisted at high frequency for more than 2 years and significantly reduced dengue incidence. Although these encouraging results indicate that w AlbB releases can be an effective dengue control strategy, the long-term success depends on w AlbB maintaining high population frequencies and virus transmission inhibition, and both could be compromised by Wolbachia– host coevolution in the field. Here, w AlbB-carrying Ae. aegypti collected from the field 20 months after the cessation of releases showed no reduction in Wolbachia density or tissue distribution changes compared to a w AlbB laboratory colony. The w AlbB strain continued to induce complete unidirectional cytoplasmic incompatibility, showed perfect maternal transmission under laboratory conditions, and retained its capacity to inhibit dengue. Additionally, a field-collected w AlbB line was challenged with Malaysian dengue patient blood, and showed significant blocking of virus dissemination to the salivary glands. These results indicate that w AlbB continues to inhibit currently circulating strains of dengue in field populations of Ae. aegypti , and provides additional support for the continued scale-up of Wolbachia wAlbB releases for dengue control. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.

AwAlbBWolbachiatransinfection displays stable phenotypic effects across divergentAedes aegyptimosquito backgrounds

“…2011). Wolbachia infections can also be used to suppress mosquito populations through cytoplasmic incompatibility (M ains et al . 2019; Z heng et al .…”

“…2018; R yan et al . 2019) but did not reach high frequencies in many parts of Niterói and Rio de Janeiro in Brazil despite multiple rounds of releases (G esto et al 2021; P into et al . 2021).…”

“…2017b), prompting its deployment in field trials in Kuala Lumpur, Malaysia. Releases of w AlbB led to stable population replacement in some trial locations with a corresponding reduction in dengue transmission (N azni et al . 2019).…”

“…2019). Aedes aegypti carrying w AlbB have also been released in population suppression programs that rely on cytoplasmic incompatibility to reduce wild female fertility (M ains et al . 2019; C rawford et al .…”

“…Host genotype can influence Wolbachia’s effects on host fitness (R eynolds et al . 2003; D ean 2006; K yritsis et al . 2019; C arvalho et al .…”