Integration of irradiation and cytoplasmic incompatibility to facilitate a lymphatic filariasis vector elimination approach

As part of a current global campaign, mass drug administration (MDA) has effectively reduced lymphatic filariasis prevalence, but mosquito vector biology can complicate the MDA strategy. In some regions, there is evidence that the goal of LF elimination cannot be attained via MDA alone. Obligate vector mosquitoes provide additional targets for breaking the LF transmission cycle, but existing methods are ineffective for controlling the primary vector throughout much of the South Pacific, Aedes polynesiensis. Previous work has demonstrated the feasibility of an A. polynesiensis population elimination strategy based upon mass repeated releases of Wolbachia induced cytoplasmically incompatible (CI) males. However, with the reduction in population size due to CI-induced sterility, there is an increasing probability that accidental female releases will permit the establishment of a new infection type, resulting in population replacement instead of population elimination. To avoid the release of fertile females, we hypothesize irradiation could be used to sterilize/neutralize accidentally released females. In this study, A. polynesiensis pupae were irradiated at differing levels to determine a dose that results in sterility of females but does not affect male fitness. Females were sterilized and male fitness was not adversely affected with an irradiation dose of 40 Gy. Subsequent laboratory assays examining male mating competitiveness also demonstrate males irradiated at 40 Gy are equally competitive with un-irradiated males. Results support examination of efficient means to irradiate large quantities of pupae, to facilitate a lymphatic filariasis vector elimination approach.