This site needs JavaScript to work properly. Please enable it to take advantage of the complete set of features!
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

NIH NLM Logo
Log in
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Jul 2;9(7):e0003864.
doi: 10.1371/journal.pntd.0003864. eCollection 2015.

Suppression of a Field Population of Aedes aegypti in Brazil by Sustained Release of Transgenic Male Mosquitoes

Affiliations

Suppression of a Field Population of Aedes aegypti in Brazil by Sustained Release of Transgenic Male Mosquitoes

Danilo O Carvalho et al. PLoS Negl Trop Dis. .

Abstract

The increasing burden of dengue, and the relative failure of traditional vector control programs highlight the need to develop new control methods. SIT using self-limiting genetic technology is one such promising method. A self-limiting strain of Aedes aegypti, OX513A, has already reached the stage of field evaluation. Sustained releases of OX513A Ae. aegypti males led to 80% suppression of a target wild Ae. aegypti population in the Cayman Islands in 2010. Here we describe sustained series of field releases of OX513A Ae. aegypti males in a suburb of Juazeiro, Bahia, Brazil. This study spanned over a year and reduced the local Ae. aegypti population by 95% (95% CI: 92.2%-97.5%) based on adult trap data and 81% (95% CI: 74.9-85.2%) based on ovitrap indices compared to the adjacent no-release control area. The mating competitiveness of the released males (0.031; 95% CI: 0.025-0.036) was similar to that estimated in the Cayman trials (0.059; 95% CI: 0.011-0.210), indicating that environmental and target-strain differences had little impact on the mating success of the OX513A males. We conclude that sustained release of OX513A males may be an effective and widely useful method for suppression of the key dengue vector Ae. aegypti. The observed level of suppression would likely be sufficient to prevent dengue epidemics in the locality tested and other areas with similar or lower transmission.

PubMed Disclaimer

Conflict of interest statement

I have read the journal's policy and the authors of this manuscript have the following competing interests: Those authors affiliated to Oxitec Ltd. (ARM, DOC, RL and LA) are/or were employees of this company, which therefore provided salary and other support for the research program. Also, such employees may have shares or share options in Oxitec Ltd. Both Oxitec Ltd. and Oxford University have one or more patents or patent applications related to the subject of this paper. LG, CAD, MLC, AM have no patent interests, shares, or share options in Oxitec or any other entity for this technology. This does not alter our adherence to all PLOS policies on sharing data and materials.

Figures

Fig 1
Fig 1. Itaberaba study area.
Untreated control area and treatment areas (A and B). Ovitrap distribution is shown for the period 21/11/2011–19/9/2012; open circles = 1 trap house-1, solid circles = 2 traps house-1. Adult BG Sentinel trap distribution for the period 10/7-25/9/2012 is also shown (open diamonds). Control area = 43.0 Ha, Area A = 5.5 ha, Area B = 5.5 ha.
Fig 2
Fig 2. Field data.
(A) Weather Data. Temperature and weekly rainfall. (B) Releases and fluorescence. Weekly numbers of adult males released per hectare and percentage of larvae recovered from ovitraps in treated areas with the OX513A transgene as detected by fluorescence. (C) Relative ovitrap index. Relative Ovitrap Index (Treated/Control) in treated areas A and B. The horizontal line represents an equal value of ovitrap index in treated areas and control area. (D) Adult density in treated area and Ovitrap index in control area. Estimated adult wild population of Ae. aegypti per hectares (error bars = 95% CI) in treated area and ovitrap index in control area. Overall. There is a clear decrease in relative ovitrap index and estimated wild male population from March 2012 to September 2012 following the increase in fluorescence induced by the increased releases while the ovitrap index in the control area remains relatively stable.
Fig 3
Fig 3. Rangefinder study.
Number of OX513A males released and corresponding % fluorescent larvae recovered from ovitraps. Error bars = 95% CI. The releases were fairly constant over the 6-week period, resulting in a presumed stable population of sterile males in the area, after an equilibration period related to adult male lifespan. The first fluorescent larvae were detected one week after the first release and the proportion of fluorescent larvae stabilized around 10% during the third week of releases until two weeks after the releases stopped.

References

    1. Bhatt S, Gething PW, Brady OJ, Messina JP, Farlow AW, Moyes CL, et al. The global distribution and burden of dengue. Nature. 2013;496:504–7. 10.1038/nature12060 - DOI - PMC - PubMed
    1. WHO-TDR. Dengue: guidelines for diagnosis, treatment, prevention and control. Geneva: WHO; 2009. - PubMed
    1. de Souza RP, Rocco IM, Maeda AY, Spenassatto C, Bisordi I, Suzuki A, et al. Dengue Virus Type 4 Phylogenetics in Brazil 2011: Looking beyond the Veil. PLoS Negl Trop Dis. 2011;5(12):e1439 10.1371/journal.pntd.0001439 - DOI - PMC - PubMed
    1. Shepard DS, Coudeville L, Halasa YA, Zambrano B, Dayan GH. Economic Impact of Dengue Illness in the Americas. The American Journal of Tropical Medicine and Hygiene. 2011;84(2):200–7. 10.4269/ajtmh.2011.10-0503 - DOI - PMC - PubMed
    1. Luz PM, Grinsztejn B, Galvani AP. Disability adjusted life years lost to dengue in Brazil. Tropical Medicine & International Health. 2009;14(2):237–46. - PubMed

Publication types

Full text links
Public Library of Science full text link Public Library of Science Free PMC article
Cite

AltStyle によって変換されたページ (->オリジナル) /