Aseptic technique has reduced the reproductive capacity of Aedes albopictus mosquitoes in Duparc . by 50%

The construction of a large-scale breeding facility for a local line of tiger mosquitoes demonstrates the progress made by IRD and its partners in developing this technology on the island. Since sterile insect engineering (SIT) relies on continuous stocking of large numbers of competitive sterile males, it is essential to establish an efficient system for mass breeding of mosquitoes. Extracted from a pei strain of Aedes albopictus obtained from Sainte-Marie, these sterile male mosquitoes are produced in the new insect farm, inaugurated on June 29.

As part of a pilot phase to demonstrate the effectiveness of SIT in the fight against Aedes albopictus, the release of sterile male mosquitoes officially began in the Duparc Nord district on July 22, 2021. , when the mosquito population is relatively low.

These release of sterile male mosquitoes are monitored by provincial decree, subject to endorsement by the Council of Ministers on Environment and Technology and Health Risks (CODERST) and prior consent from residents. Duparc.

Mid-term campaign status

Since 22 July 2021, and after 6 months of continuous intervention, 22 release of sterile male mosquitoes have been performed at the Duparc pilot site. Each release includes between 120,000 and 150,000 sterile males, with more than 4 million sterile male mosquitoes released into the wild.

To make them happen, a team of eight engineers and technicians work tirelessly in the new breeding unit to produce more than 200,000 sterile males per week.

The projected period for these releases is 12 months, approximately twenty releases of sterile male mosquitoes will still be made, at a rate of one release per week through July 2022.

TIS .’s effective monitoring system and strategy

The strategy implemented is integrated and based on five main actions:

– Communication to inform people about the actions taken.

– The mobilization of residents to destroy artificial spawning sites.

– An additional door control action to mechanically eliminate indoor mosquito breeding sites.

– Weekly stocking of 6,000 purebred males/ha on an area of ​​20ha, at various locations around residential areas and along roadsides.

– Monitor mosquito population with traps, to measure survival, dispersal and competitiveness of sterile males released into the wild.

Scientific evaluation of the effectiveness of these releases focuses on two questions:

(i) Will the release of sterile males change the fertility and reproductive capacity of wild mosquitoes?

(ii) Does tiger mosquito abundance decrease when males are spayed and released frequently?

Initial results are largely satisfactory

The team determined the effectiveness of SIT by comparing mosquito densities in the treated area in Duparc and the untreated control area in Bois Rouge. A first analysis of the results after 6 months of release and evaluation showed that the fertility of wild mosquitoes in Duparc decreased by almost 50% compared with the control area. The next results, reasonably expected, after the reduction in the fertility of wild female mosquitoes, are:

– Significant reduction in the number of mosquitoes,

Impact on nuisance level and risk of dengue virus transmission.

With these encouraging and promising results for the future, IRD and its partners’ goal is to continue releasing through the end of July 2022, remaining at the weekly rate. Final results will be made available by the end of September after final analysis to demonstrate the feasibility of this vector control technique and lay the groundwork for an industrial project to release mosquitoes into the air. coincide on a large scale.

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