Genetic control of mosquitoes HEALTHY PEOPLE HEALTHY ENVIRONMENT Luke Alphey, Founder and Chief Scientific Officer Visiting Professor in Zoology, University.

Genetic control of mosquitoes

O X F O R D I N S E C T T E C H N O L O G I E S HEALTHY PEOPLE HEALTHY ENVIRONMENT

Luke Alphey, Founder and Chief Scientific OfficerVisiting Professor in Zoology, University of Oxford

Oxitec Ltd

Based in Oxford, UK,30 employees

Founded in 2002 to commercialise new technology from Oxford University

Control of insects Agricultural pests

Public Health (mosquitoes)

Injecting DNA into mosquito eggs

Introduction Why?

Pest insects cause $$bn damage and transmit major diseases

How?

Engineered sterile males

RIDL®: Release of Insects carrying a Dominant Lethal genetic system

Genetics, molecular biology

When?

Initial strains successfully tested in field

Marker-only moth: USA 2006

RIDL mosquitoes: Cayman Islands 2009, Malaysia 2010, Brazil 2011

Increased Risk of Vector Borne Disease Dengue - growing global pandemic

Over 100 million cases annually Severity increasing No specific medication or vaccine

Chikungunya - emerging threat 1.8 million cases in last 6 years

(WHO) Reunion (2005) had 266,000 cases

and 254 deaths Italy (2007) – 197 cases and I death

Oxi

tec/

Nim

mo

Dengue control

WHO

RIDL®

RIDL

WHO

A Genetic Solution Release engineered sterile

males to prevent mosquito reproduction and so control dengue “birth control for mosquitoes”

Sterile male mosquitoes actively seek females Find mosquitoes better than

human inspectors

Based on Sterile Insect Technique How it works

Rear millions of insects Sterilise with irradiation Release over wide area Sterile males mate with wild

females: progeny don’t survive Pest population declines

Species-specific Used for over 50 years

New World Screwworm Eradicated

RIDL insects are genetically sterile Repressible Release homozygous males

X

RIDL: fail-safe / replacing radiation

Introgression of genes through male line

X

Bi-sex lethal Female-specific lethal

effectortTAtetOpromoter

Antidote (Tc)

death

RIDL®: molecular biology

Thomas et al. 2000 Science 287: 2474-6Fu et al. 2010 PNAS 107: 4550-4

Controllable Gene Expression

Female specificity

Female death

Act4-tTA + tetO-DsRed

OX3545F

effectortTA

tetO + promoterpromoterAct4

(DsRed)

Flight muscles only

OX3604C RIDL mosquitoes

Males FemalesFlightless mosquitoes cannot survive in wild (or find hosts). Unable to mate even in laboratory. Males have normal flight

ability, as have females given antidote as larvae.

fsRIDL phased trials – large lab cage trials

RIDL cage trials performed in Colorado State University (Megan Wise, Bill Black) showing suppression of target population

RIDL insects are genetically sterile Repressible Release homozygous males

X

RIDL: fail-safe / replacing radiation

Introgression of genes through male line

X

Bi-sex lethal Female-specific lethal

Development trials First open release Grand Cayman 2009

mating of RIDL males to local females excellent mating competitiveness provided data for suppression trial 2010

10km

500m

0

Each Area approx 16 Ha (40 acres)

No conventional control for Aedes aegypti

Release period May-Oct 2010 with pre- and post-release monitoring

Cayman field trial 2010

1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct0

20

40

60

80OVITRAP INDEX treated (A) & non-treated (C)

EE - Area C Polynomial (EE - Area C)EE - Area A

Ovi

trap

Inde

x (%

)

Trial was complete success; all endpoints met Clear suppression from early August

Sustained release of RIDL OX513A males can suppress a field population of Aedes aegypti mosquitoes Maximum degree of suppression limited by immigration

GM mosquitoes can perform successfully in the field

500m0

Bringing new technology to the field

Technical

CommunityRegulatory

RIDL

effectortTAtetOpromoter

Antidote (Tc)

death

Nature

Regulatory Progress

The USDA completed (2008) an Environmental Impact Statement (EIS) on the use of autocidal technology (RIDL) in fruit flies and PBW Record of Decision: this is the environmentally preferred alternative

North American Plant Protection Organization (NAPPO) standard signed late 2007

MosqGuide: WHO/TDR develop guidance for use of GM mosquitoes for disease control

Oxitec transgenic insect approvals Multiple movement and contained trial approvals (Medfly, Mexfly, pink

bollworm, Aedes aegypti, Ae. albopictus) Open field release approvals in the USA (PBW 2006,7,8)

Released 15 million Oxitec pink bollworm from aircraft over 2500 acres (2008)

Community Engagement

Focus Group: reactions to Oxitec approach

• breakthrough!• good news• kills larvae• good – something worth trying going forward• provides immediate solution / result in preventing

Dengue• seen as a long term solution cf other methods which

are all seen as short term• some even welcome the research team to test the

technique in their community

From TNS Malaysia

Community engagement

• Malaysian Health Minister Datuk Seri Liow Tiong Lai “We see it as the most efficient and fastest way in eradicating Aedes mosquitoes from our local environment,” Liow said, adding that Aedes is not a species endemic [native] to Malaysia. Monday 11th Oct 2010

Frequently Asked Questions

Will the genetic modification spread outside the release area?

The released mosquitoes and their progeny will die so this is a ‘self limiting’ approach, with no permanent change to the wild mosquito population. The large fitness cost (and no component advantage) also prevents spread.

Do mosquitoes provide valuable ecosystem services (e.g. food chain, pollinators)?

Aedes aegypti originated in Africa and only achieved pan-tropical distribution in the 1930s. Therefore in most countries it is not a native species. There are no birds, fish or other insects that feed exclusively on it and therefore reducing the number of Aedes aegypti is most unlikely to have negative impacts on the environment.

If one mosquito suppressed, will a worse one replace (niche replacement)?

Aedes aegypti it occupies an unusual, human-associated niche normally empty in its absence. Aedes albopictus, a potential alternative, is an inferior vector of dengue. RIDL strains are also available for Aedes albopictus.

Can we release enough (feasibility, economics)?

Long history of success and data from SIT implies ‘yes’, as do modelling and data so far.

Acknowledgements

O X F O R D I N S E C T T E C H N O L O G I E S HEALTHY PEOPLE HEALTHY ENVIRONMENT

Greg SimmonsBob Staten (rtd)Tom Miller (UCR)

IMR, Malaysia

Lee Han LimPI: Tony James

PI: John Mumford

Angi HarrisBill Petrie

Thank you…