Table 4.

The Wolbachia approach in the Pacific region [50].

Aim: The World Mosquito Program, with a focus on the Pacific region, aims to eradicate viruses like DENV, CHIKV, and ZIKV by cutting of the transmission routes for mosquito-borne diseases. By infecting larvae with a particular strain of the bacterium Wolbachia (wMel), the wild mosquito population as well as its vector capacities will decrease over time, as well as facilitate mosquito suppression, resulting in reduced virus transmission levels.

Methods: The Wolbachia approach is currently applied by the World Mosquito Program in Fiji, Vanuatu, Kiribati, and Sri Lanka. Mosquito larvae are infected in laboratories with a specific strain of Wolbachia, which is originally taken from Aedes reversi, a related Aedes species. After the infection, the Wolbachia carrying male mosquitoes are released in target areas in order to breed with wild mosquitoes and grow in population.

Results: Wolbachia transmission could be identified from infected male mosquitoes to wild female mosquitoes (horizontal), as well as from parent to offspring inside the mosquito eggs (vertical). As a result, two effects could be observed: First, Wolbachia strains inside the mosquito reduce the replication of viruses, such as DENV, ZIKV, and CHIKV. Second, mosquito eggs may not hatch and, consequently, mosquito populations may be suppressed. This method has been successfully applied in Guangzhou, China, where scientists nearly eliminated Aedes albopictus mosquitoes from two islands by using the Wolbachia technique, with promising long-term effects: Studies in inner Cairns suburbs already showed that the Wolbachia strain can exist in mosquito populations for more than eight years [49]. According to Hervé Bossin, the project’s lead scientist, the Wolbachia approach is expected to help solving the mosquito problem in Island States within the next ten years.