From The Lancet

As stated by Laith Yakob and Thomas Walker,1 the need for efficient and novel mosquito control methods in the context of the Zika virus outbreak is undisputed.

However, technologies such as Release of Insects carrying Dominant Lethal genes (RIDL) are not flawless. Transgenic Aedes aegypti larvae die if they are not fed with a diet supplemented with an antibiotic (tetracycline). However, deprivation of the mosquitoes from the antibiotic results in 5% survival of transgenic larvae,2 resulting in the uncontrolled diffusion of the transgene in large-scale deployment in the field. Moreover, tetracycline is widespread in surface waters in countries where the Zika virus is rapidly progressing, including Brazil.3

By contrast, the Sterile Insect Technique (SIT ) is safe and is undergoing field validation against A aegypti and Aedes albopictus, but has received little attention to date. SIT does not raise public opposition or require regulatory approvals and no intellectual property issues are involved. Most importantly, the released sterilised insects cannot become established in nature. We believe that the SIT could be further boosted by use of sterile males as conveyors of biocides to their wild counterparts.4 A European project, titled Revolutionizing insect control, was launched in 2016 to study the dispersion of densovirus (a species- specific natural entomopathogenic virus)5 from sterile males to wild females and then to their larval habitats as a result of their skipping oviposition behaviour (figure). This strategy might enlarge the effect of the SIT, offering unprecedented opportunities for the control of Zika virus and other mosquito-borne diseases.

Although transgenic mosquitoes might be exciting to the media, more biosafe alternatives should not be neglected.
We declare no competing interests. This project has been selected for funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 682387—REVOLINC). This Correspodence reflects only the authors’ views and the Agency is not responsible for any use that may be made of the information it contains.
Copyright © Bouyer et al. Open Access article distributed under the terms of CC BY-NC-ND.

*Jérémy Bouyer, Fabrice Chandre, Jérémie Gilles, Thierry Baldet [email protected]
Unité Mixte de Recherche Contrôle des Maladies Animales Exotiques et Emergentes, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD),
34398 Montpellier, France (JB, TB); Unité Mixte de
Recherche Maladies infectieuses et vecteurs:
écologie, génétique, évolution et contrôle, Institut de Recherche pour le Développement, Montpellier, France (FC); and Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria (JG)
1 Yakob L, Walker T. Zika virus outbreak in the Americas: the need for novel mosquito control methods. Lancet Glob Health 2016;
4: e148–49.

2 Curtis Z, Matzen K, Oviedo MN, et al.
Assessment of the impact of potential
tetracycline exposure on the phenotype of
Aedes aegypti OX513A: implications for field
use. PLoS Negl Trop Dis 2015; 9: e0003999.
3 Locatelli MAF, Sodré FF, Jardim WF.
Determination of antibiotics in Brazilian
surface waters using liquid chromatography–
electrospray tandem mass spectrometry.
Arch Environ Contam Toxicol 2011; 60: 385–93.
4 Bouyer J, Lefrançois T. Boosting the sterile insect technique to control mosquitoes. Trends Parasitol 2014; 30: 271–73.
5 Carlson J, Suchman E, Buchatsky L.
Densoviruses for control and genetic
manipulation of mosquitoes. Adv Virus Res
2006; 68: 361–92.

IMAGE:
A Release of sterile males coated with a densovirus
B Adult horizontal transmission to the breeding site
C Multiplication of the densovirus plus larval horizontal transmission
D Adult vertical transmission to new breeding sites
(A) Sterile males of Aedes aegypti or Aedes albopictus are coated with crystalised densovirus (AeDNV)5 and released by air. (B) Part of the virus is transmitted to the females during mating and the females that are induced sterile carry it to their breeding sites. (C) The virus contaminates larvae in the breeding sites and multiplies with a long-term persistence. (D) Some larvae survive and emerge as contaminated adults that subsequently deliver the larvicide to neighbouring larval habitats.

SOURCE: www.thelancet.com/lancetgh Vol 4 June 2016

EDITOR: This was sent to us by Anthony Jackson