United States

FKMCD-logo-PNG-large-e1413831490655Oxitec and the Florida Keys Mosquito Control District (FKMCD) are collaborating on a field trial for the OX513A Aedes aegypti mosquito.

For more information you can view our educational flyers here and here.

Update: FDA publishes preliminary finding of no significant impact

The FDA has released a preliminary finding of no significant impact (FONSI) on Oxitec’s self-limiting mosquito for an investigational trial in the Florida Keys.

In March, Oxitec’s draft Environmental Assessment and the preliminary FONSI were made available for public comment. The public comment period ended May 13th. Copies of the documents are available on the FDA-CVM website here.

Wild Mosquito Problem

Aedes aegypti mosquitoes are a non-native species in the USA. They are more than just a nuisance as they can spread serious diseases such as dengue fever and chikungunya. Dengue fever and chikungunya are currently not an active health threat in the Florida Keys including Key West as FKMCD has been working hard to reduce the Aedes aegypti pest. They are looking for helpful ways to keep mosquito populations down to an acceptable level and the Oxitec technology is a new tool in the fight against mosquitoes.

Technology Benefits

160321-lets-keep-florida-safe_RGB_large

If we use fewer insecticides this will allow more beneficial predators and insects to flourish. Both the released mosquitoes and their offspring will die – they do not stay in the environment. This approach targets only the Aedes aegypti mosquitoes that can spread disease because the Oxitec males only produce offspring with their own species.

Project Plan

key-haven-map

Oxitec and FKMCD are working together to inform the community about the mosquito releases and to answer questions. If FDA agrees that releases can proceed following their review, we anticipate starting in 2015. Oxitec male mosquitoes would be released up to 3 times a week. Project results will be made available to the public.

The Food and Drug Administration Center for Veterinary Medicine (FDA-CVM) is working with other agencies including the Centers for Disease Control and Prevention (CDC) and Environmental Protection Agency (EPA) for federal regulation of this project. There will be no releases until the FDA has completed an evaluation. The FDA will issue public notification when it publishes the draft Environmental Assessment for comment on www.regulations.gov. For more information click here.

Publications

www.oxitec.com/publications

Questions?

floridatrial@oxitec.com

questions@keysmosquito.org

FAQ

Here are answers to commonly asked questions about the Oxitec mosquito. These also address questions submitted at the Key West town hall meeting (see below), and these are noted in parentheses.

What is dengue?

Dengue fever is a severe, flu-like illness that affects infants, young children and adults. There is no available vaccine or specific medicine for dengue fever. Dengue fever is transmitted by the bite of an Aedes aegypti mosquito infected with any one of the four versions of the dengue virus (and a fifth serotype of dengue has now been discovered in Malaysia). Symptoms appear in 3–14 days (average 4–7 days) after the infective bite. Dengue haemorrhagic fever (DHF) and Dengue Shock Syndrome (DSS) are potentially lethal complications, particularly in children, and early clinical diagnosis and careful clinical management by experienced physicians and nurses is necessary to reduce the number of fatalities.

Dengue can only be transmitted by the bite of an infected mosquito and only the female mosquitos bite. The main vector is the mosquito Aedes aegypti, which originated from Africa and has spread around the world, largely in the last 50 years and, as it has done so, dengue fever has followed and increased dramatically.

The global numbers of dengue cases have grown 30 fold in only 50 years because current control methods, relying mostly on insecticides are not adequate to control this mosquito.

Each year there are an estimated 400 million dengue infections, with 500,000 cases so severe they require hospitalisation and 22,000 deaths, many of them children. New approaches are needed.

Further Reading:

Bhatt, S., Gething, P. W., Brady, O. J., Messina, J. P., Farlow, A. W., Moyes, C. L., … & Hay, S. I. (2013). The global distribution and burden of dengue. Nature, 496(7446), 504-507.

WHO Dengue Fever factsheet: http://www.who.int/mediacentre/factsheets/fs117/en/#content

CDC Dengue Fever http://www.cdc.gov/Dengue/

What is chikungunya?

Chikungunya is a viral disease transmitted to humans by infected mosquitos. It causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash.

The disease shares some clinical signs with dengue, and can be misdiagnosed in areas where dengue is common. There is no available vaccine or specific medication for the disease. Treatment is focused on relieving the symptoms.

Until recently the disease occurred mainly in Africa, Asia and the Indian subcontinent. In recent decades mosquito vectors of chikungunya have spread to Europe and the Americas. In 2007, disease transmission was reported for the first time in a localized outbreak in north-eastern Italy. In December 2013 the first case was reported in the Caribbean and within in 12 months there were an estimated 1 million cases in the region and 11 cases of locally acquired chikungunya have been reported in Florida in 2014 according to the CDC.

Further reading:

WHO chikungunya factsheet: http://www.who.int/mediacentre/factsheets/fs327/en/

CDC chikungunya: http://www.cdc.gov/chikungunya/geo/united-states.html

How does the Oxitec mosquito work? (Q1,6,7,8)

The Oxitec mosquito (also known as OX513A) control method is based on the Sterile Insect Technique (SIT), which is an environment-friendly, species-specific approach. SIT has been used very successfully in agriculture for over 50 years. SIT works by releasing sterile insects of a target species. The sterile males compete with the wild males for female insects. If a female mates with a sterile male then it will have no offspring, reducing the next generation’s population. Repeated release of insects can reduce the insect population to very low levels.

SIT is currently restricted by the need to irradiate the insects to sterilize them. For some species, for example mosquitos, the dose of radiation required to sterilize the males also damages their fitness to the extent that SIT cannot be used effectively.

Oxitec scientists developed a more carefully targeted way to produce the same ‘sterilisation’ effect using genetic control instead of radiation. Oxitec insects are given two genes, a color marker and the ‘self-limiting’ pest control gene which causes offspring to die. The modified male insects are released to mate with wild pest females, they pass on these two genes, and over 95% of the offspring die before reaching adulthood. The pest population is brought under control with successive releases.

The color marker

All Oxitec insects and their offspring express a fluorescent protein that can be seen using a special light. In the Oxitec mosquito this can be seen at the larval and pupal stage. The color marker is an important part of our approach. We can collect larvae from the area of release and use the color marker to see how many are Oxitec mosquitos and how many are wild pest mosquitos. Using this color marker we can adjust the number of Oxitec mosquitos we need to release and we can monitor their mating success. We can then increase or decrease the number of mosquitos released to optimise release efficiency and control of pest Aedes aegypti. The ability to monitor the insects we release and the effect on the target population in real-time, is a key feature of this approach.

We believe it is very important to maintain control of one’s product. With the color marker we can detect our product in the field and monitor its effect closely to offer mosquito control agencies the most cost effective release program to control pests.

The ‘self-limiting’ gene

We have introduced a gene into the mosquitos so that their cells do not function as they should, and this effect is specific to the mosquito (also known as a ‘self-limiting’ gene because it makes mosquito reproduction a dead end – the offspring do not survive to adulthood). As a result over 95% of the Oxitec mosquitos die before they become adults and do not live to breed further, and the population is reduced. Aedes aegypti do not produce offspring with other species so the control is species-specific and the genes don’t spread. The released mosquitos and their offspring die and so the genes also do not persist in the environment. The color marker and self-limiting genes are non-toxic and non-allergenic, so if animals were bitten by Oxitec mosquitos, or predators ate Oxitec mosquitos, it would be the same as getting bitten by or eating wild ones.

We need to be able to rear millions of males per week, so we have engineered the mosquito to make production cost effective. If the mosquito larvae in the production unit are given tetracyclines, these act as an antidote inactivating the self-limiting gene. The antidote is not present in sufficient quantities in the environment to allow inactivation of the self-limiting gene, so offspring of the Oxitec mosquito will not reach adulthood.

Further reading:

“Sterile Insect Technique: Principles and Practice in Area-Wide Integrated Pest Management,” 2005, edited by V.A. Dyck, J Hendricks and A.S Robinson.

Alphey, L., Benedict, M.Q., Bellini, R., Clark, G.G., Dame, D.A., Service, M.W. and Dobson, S.L. (2009) Sterile-insect methods for control of mosquito-borne diseases – an analysis. Vector-Borne and Zoonotic Diseases, Vol. 10, Issue 3, 295-311.

Gossen, M. and Bujard, H. (1992) Tight control of gene expression in mammalian cells by tetracycline-responsive promoters. PNAS 89(12): 5547-5551

Lin, H., McGrath, J., Wang, P. and Lee, T. (2007) Cellular Toxicity Induced by SRF-Mediated Transcriptional Squelching. Toxicological Sciences 96 (1) 83-91.

FDA (Food and Drug Administration) (2010). NPC 000004: Agency Response Letter on DsRed2 Center for Food Safety, ed. (Washington DC: Food and Drug Administration).

Nordin, M.O., Donald, W., Ming, H.W., Ney, G.T., Mohamed, A.K., Halim, A.A.N., Winskill, P., Hadi, A.H., Lacroix, R., Scaife, S., et al. (2012). Oral ingestion of transgenic RIDL Ae. aegypti larvae has no negative effect on two predator Toxorhynchites species. PLoS One 8.

Lacroix, R., McKemey, A.R., Raduan, N., Kwee Wee, L., Hong Ming, W., Guat Ney, T., Rahidah, A.A.S., Salman, S., Subramaniam, S., Nordin, O., et al. (2012). Open field release of genetically engineered sterile male Aedes aegypti in Malaysia. PLoS One 7, e42771.

Harris, A. F., Nimmo, D., McKemey, A. R., Kelly, N., Scaife, S., Beech, C., Petrie, W., and Alphey, L. (2011) Field performance of engineered male mosquitos. Nature Biotechnology 29: 1034-1037.

Harris, A.F., McKemey, A.R., Nimmo, D., Curtis, Z., Black, I., Morgan, S.A., Oviedo, M.N., Lacroix, R., Naish, N., Morrison, N.I., et al. (2012). Successful suppression of a field mosquito population by sustained release of engineered male mosquitos. Nat Biotechnol 30, 828-830.

Phuc, H.K., Andreasen, M.H., Burton, R.S., Vass, C., Epton, M.J., Pape, G., Fu, G., Condon, K.C., Scaife, S., Donnelly, C.A., et al. (2007). Late-acting dominant lethal genetic systems and mosquito control. BMC biology 5, 11.

Alphey, L., McKemey, A., Nimmo, D., Neira Oviedo, M., Lacroix, R., Matzen, K., and Beech, C. (2013). Genetic control of Aedes mosquitos. Pathog Glob Health 107, 170-179.

Alphey, L., Nimmo, D., O’Connell, S., and Alphey, N. (2008). Insect population suppression using engineered insects. Adv Exp Med Biol 627, 93-103.

Why do a trial in Florida Keys if there has been no dengue since 2010?

The aim is to keep it that way. FKMCD are world leaders in mosquito control but with current methods they can only reduce the Aedes aegypti population by up to 50% at best. This is still above the disease transmission threshold according to the Focks model (Focks et al. 2000) so there is still a risk of disease transmission. While dengue remains endemic in Central America and the Caribbean, Chikungunya has been rapidly spreading through the region with an estimated 1 million cases arising in just one year according to the CDC. There is no available vaccine or cure for dengue or chikungunya so prevention is the best defense. FKMCD is looking for new tools to provide better control of this mosquito vector to keep the Keys free of these diseases.

The Oxitec mosquito has already been through multiple trials in different countries and in every case this approach has cut the pest mosquito population by at least 90%. It has now been approved for commercial use in Brazil by their National Biosafety Committee (CTNBio).

Further reading:

Focks D et al. 2000. Transmission thresholds for dengue in terms of Aedes aegypti pupae per person with discussion of their utility in source reduction efforts. American Journal of Tropical Medicine and Hygiene, 62(1):11–18.

Do all mosquitos spread dengue and chikungunya?

No. Aedes aegypti is the species of mosquito which is primarily responsible for spreading dengue. Also, only female mosquitos can spread dengue or chikungunya. Males do not bite or spread disease (in fact males cannot bite). Other Aedes species such as Aedes albopictus, can also spread dengue and chikungunya, but Aedes aegypti is overwhelmingly the main vector, and it is this species that is responsible for almost all of the dengue epidemics around the world. Aedes albopictus is often cited as a dengue vector, and can spread the disease, but it is not very efficient. Other mosquito species bite humans but do not spread dengue fever.

Further reading:

Jansen, C. C. and N. W. Beebe (2010). The dengue vector Aedes aegypti: what comes next? Microbes Infect. 12(4): 272-279.

Lambrechts L, Scott TW, Gubler DJ. (2010). Consequences of the expanding global distribution of Aedes albopictus for dengue virus transmission. PLoS Negl Trop Dis. 4(5): 3646.

What happens if Aedes aegypti is controlled, could another species like albopictus move in? (Q4,7,12)

Aedes aegypti is overwhelmingly the major threat in terms of its ability to efficiently spread dengue and chikungunya. Ae. albopictus has the capacity to spread disease but is relatively inefficient at disease transmission. Ae. aegypti feeds almost exclusively on humans. It lives in and around the home and can take multiple bites to get a blood meal. These features make it highly effective at spreading disease once a person has entered an area carrying the virus. Ae. Albopictus, by contrast, is an aggressive biter and will tend to secure its blood meal more easily from a variety of sources. It is less selective about what it bites – so it will bite dogs, birds, etc. which are unaffected and do not act as a source for onward transmission to people. The two species can occupy the same habitat but Ae. aegypti is predominately restricted to areas of human habitation whereas Ae. albopictus is not and tends to live more at the fringes of town, in forested areas and under brush, etc.

In areas of overlap, it is likely there will be an element of competition for breeding sites, but there is no ‘general rule’ as to whether one species reduces in numbers, if there will be an effect on the other. However what is clear is that Ae aegypti is the major threat in terms of disease and it is the major target of mosquito control programs aiming to reduce disease risk. Even if the numbers of Ae aegypti fell and Ae albopictus were seen to rise, the disease threat would still be significantly reduced.

FKMCD monitor both mosquitos on an ongoing basis and Oxitec also monitor both species in our field trials and projects, and will do so in this trial.

Why not just use insecticides? (Q7)

Insecticides are designed to kill insects and they can be very effective, although the development of insecticide resistance can affect their level of control. In the Florida Keys, Aedes aegypti has developed resistance to four of the six insecticides used. No new chemicals for insecticides have been introduced for vector control in over 40 years.

Aedes aegypti generally only fly short distances (about 200 yards in their lifetime) so they tend to stay where they are in and around human dwellings. A challenge of insecticide control is that a public health authority needs access to everyone’s homes to spray and treat standing water and containers on a very regular basis, otherwise they are not able to sufficiently control this mosquito. Even with this level of access, it is still difficult to find and spray every area. As a result, even the best funded and most organised public health authorities cannot successfully control Aedes aegypti in urban environments with more than 30% efficacy, (up to 50% for FKMCD, world leaders in mosquito control), and this is insufficient to prevent disease outbreaks. This is why there is a pressing need to develop new tools to control this mosquito species.

Further reading:

Ballenger-Browning K.K, Elder J.P., (2009) Multi-modal Aedes aegypti mosquito reduction interventions and dengue fever prevention. Tropical Medicine and international health 14(12): 1542-1551.

Have Oxitec mosquitos been tested outdoors? (Q4,7,12)

Yes. From 2009, Oxitec and other groups(below) have performed open release tests of Oxitec’s Aedes aegypti (under permit from the appropriate regulators) in several countries, including the Cayman Islands, Malaysia, Panama and Brazil. In each trial Oxitec mosquitos reduced the local Aedes aegypti population by over 90%. There have been no noted adverse events or effects.

In every case to date, these mosquito trials have been carried out by external institutes or agencies. Oxitec have provided the OX513A strain and technical support. These external evaluators are:

The Mosquito Research Control Unit (MRCU) in Cayman
The Institute of Medical Research (IMR) in Malaysia
Moscamed and University of Sao Paulo in Brazil
The Gorgas Memorial Institute in Panama
In each case the institutes above are able to publish or publicise their results which they have done through a combination of publications, conference presentations, or other media.

Another example of outdoor release of a genetically engineered insect is the pink bollworm (Pectinophora gossypiella), a moth that is a pest of cotton. The US Department of Agriculture has evaluated Oxitec’s GM pink bollworms in three years of open-field and mass-rearing trials, and so far have released over 15 million GM moths in the USA. Oxitec’s strain has performed exactly as predicted in these trials. There have been no negative outcomes (whether environmental, agricultural or to human health) reported. These trials were also subject to rigorous evaluation by the US regulatory authorities before any releases occurred.

Further reading:

Harris, A. F., Nimmo, D., McKemey, A. R., Kelly, N., Scaife, S., Beech, C., Petrie, W., and Alphey, L. (2011) Field performance of engineered male mosquitos. Nature Biotechnology 29: 1034-1037.

Harris, A.F., McKemey, A.R., Nimmo, D., Curtis, Z., Black, I., Morgan, S.A., Oviedo, M.N., Lacroix, R., Naish, N., Morrison, N.I., et al. (2012). Successful suppression of a field mosquito population by sustained release of engineered male mosquitos. Nat Biotechnol 30, 828-830.

Simmons, G. S., A. R. McKemey, et al. (2011). “Field performance of a genetically engineered strain of pink bollworm.” PLoS One 6(9): e24110.

USDA (2008). Final Environmental Impact Statement Use of Genetically Engineered Fruit Fly and Pink Bollworm in APHIS Plant Pest Control Programs, United States Department of Agriculture, Marketing and Regulatory Programs, and Animal and Plant Health Inspection Service, eds. (Riverdale MD 20737: USDA).

USDA (2009). Use of Genetically Engineered Fruit Fly and Pink Bollworm in APHIS Plant Pest Control Programs: Record of Decision, U.S.D.o. Agriculture, ed. (Federal Register: Federal Register), pp. 21314 -21316.

Are Oxitec’s mosquitos compatible with mosquitos found in the Florida Keys? (Q7)

Yes. Aedes aegypti as a species is native to North Africa and has been spread around the world by human activities. Whilst it is possible for Aedes aegypti to be passively transported as adults (for example in an airplane, although there are regulations to prevent this), the main way it spreads is as eggs through the movement of freight and goods from one country to another. In Florida, Aedes aegypti is a non-native species, just as it is in Panama, Cayman and all the Americas. Oxitec mosquitos are a strain of this same species so they mate successfully. Mating studies of Oxitec’s OX513A strain have been carried out with local Aedes aegypti in many countries, showing that they’re able to compete and mate as effectively as local males.

Has the Oxitec mosquito been independently evaluated? (Q4,11,12)

Yes. Independent collaborators around the world have conducted extensive testing on Oxitec’s OX513A mosquitos since the strain was first developed in 2002.

Oxitec insects (mosquitos and other species) have been tested by independent laboratories including the Institute Pasteur in Paris, the Gorgas Memorial Institute in Panama, the Institute for Medical Research in Malaysia, University of Colorado (USA) and the United States University of Health Sciences (USUHS). The Centre for Medical and Veterinary Entomology (CMAVE) at Gainesville, FL have also tested our mosquitos in contained outdoor cage trials.

For outdoor trials, these have been carried out by the Mosquito Research and Control Unit Cayman, the Gorgas Memorial Institute in Panama, the Institute for Medical Research in Malaysia, Moscamed and the University of São Paulo in Brazil. In each of the outdoor suppression trials the wild population of Aedes aegypti in the areas has been reduced by over 90%.

The United States Department of Agriculture (USDA), the Animal and Plant Health Inspection Service (APHIS) and the Centre for Plant Health Science Technology (CPHST) have tested the same Oxitec approach in another insect species and a thorough examination of the risks and benefits has been conducted under the National Environmental Protection Act (NEPA), which concluded that the use of this technology was ‘environmentally preferable’ to alternatives. The alternatives examined included taking no action, essentially maintaining sterile insect technique through irradiation of mass-reared insects in plant pest control programs as is currently practiced, expansion of existing programs in overall size, capacity, and diversity of plant pest species, and integration of genetically engineered insects into APHIS’ plant pest control programs.

Oxitec also use accredited third-party laboratories where appropriate to carry out studies to produce data for regulatory submissions. For the Oxitec mosquitos this has included testing of potential effects on non-target organisms such as fish that eat mosquitos, determining environmental concentrations of tetracycline, and examining the potential for any toxicity or allergenicity. No adverse effects were found.

Further reading:

Lacroix, R., McKemey, A.R., Raduan, N., Kwee Wee, L., Hong Ming, W., Guat Ney, T., Rahidah, A.A.S., Salman, S., Subramaniam, S., Nordin, O., et al. (2012). Open field release of genetically engineered sterile male Aedes aegypti in Malaysia. PLoS One 7, e42771.

Kongmee, M., Nimmo, D., Labbe, G., Beech, C., Grieco, J., Alphey, L., and Achees, N. (2010). Irritant and repellent behavioral responses of Aedes aegypti male populations developed for RIDL disease control strategies. Journal of medical entomology 47, 1092-1098.

Simmons, G. S., A. R. McKemey, et al. (2011). “Field performance of a genetically engineered strain of pink bollworm.” PLoS One 6(9): e24110.

Massonnet-Bruneel, B., Corre-Catelin, N., Lacroix, R., Lees, R.S., Hoang, K.P., Nimmo, D., Alphey, L., and Reiter, P. (2013). Fitness of transgenic mosquito Aedes aegypti males carrying a dominant lethal genetic system. PLoS One 8, e62711.

USDA (2008). Final Environmental Impact Statement Use of Genetically Engineered Fruit Fly and Pink Bollworm in APHIS Plant Pest Control Programs, United States Department of Agriculture, Marketing and Regulatory Programs, and Animal and Plant Health Inspection Service, eds. (Riverdale MD 20737: USDA).

USDA (2009). Use of Genetically Engineered Fruit Fly and Pink Bollworm in APHIS Plant Pest Control Programs: Record of Decision, U.S.D.o. Agriculture, ed. (Federal Register: Federal Register), pp. 21314 -21316. http://www.gpo.gov/fdsys/pkg/FR-2009-05-07/xml/FR-2009-05-07.xml#seqnum21314

Brazilian National Committee on Biosafety Risk Assessment of OX513A mosquitos http://bch.cbd.int/database/record.shtml?documentid=105831

Harris, A. F., Nimmo, D., McKemey, A. R., Kelly, N., Scaife, S., Beech, C., Petrie, W., and Alphey, L. (2011) Field performance of engineered male mosquitos. Nature Biotechnology

Nazni, W.A., Lee, H.L., Selvi, S., Nimmo, D., and Vasan, S.S. (2009). Susceptibility status of RIDL Aedes aegytpi (L.) against conventional insecticides. Dengue Bulletin 33, 124-129.

Nordin, M.O., Donald, W., Ming, H.W., Ney, G.T., Mohamed, A.K., Halim, A.A.N., Winskill, P., Hadi, A.H., Lacroix, R., Scaife, S., et al. (2012). Oral ingestion of transgenic RIDL Ae. aegypti larvae has no negative effect on two predator Toxorhynchites species. PLoS One 8.

Bargielowski, I., Nimmo, D., Alphey, L., and Koella, J.C. (2011). Comparison of life history characteristics of the genetically modified OX513A line and a wild type strain of Aedes aegypti. PLoS One 6, e20699.

Wise de Valdez, M.R., Nimmo, D., Betz, J., Gong, H.F., James, A.A., Alphey, L., and Black, W.C.t. (2011). Genetic elimination of dengue vector mosquitos. Proc Natl Acad Sci U S A 108, 4772-4775.

What do you say to people who say that there should be informed consent?

Informed consent is a process for getting permission before conducting a healthcare intervention on a person. Our approach is emphatically not a healthcare intervention and we make no healthcare claims. Our aim is to control the mosquito population. FDA also see this as an intervention for mosquitos with no human health claims – that is why it is being regulated as an animal drug and not a human drug.

It is the case that by controlling the mosquito population we aim to reduce the risk to people of disease transmission – but that is the same goal as exists for the use of insecticides, mosquito coils, pheromones, traps, etc. What we are doing is introducing a new way to fulfil a standard and well recognized goal – to reduce the mosquito population.

Could the Oxitec mosquito harm other species in the environment such as predators like bats, fish, and frogs? (Q4,7,8,12)

The proteins of the introduced genes (color marker and self-limiting gene) are non-toxic and non-allergenic. Animals that eat the OX513A Aedes aegypti mosquito will be exposed to nutritional elements – protein, fat, carbohydrate and others – as they would from eating any mosquito, but they cannot take up genes through this route.

Aedes aegypti mosquitos only mate successfully with their own species. They cannot produce viable offspring with other insects in the wild, not even with other species of mosquito. Therefore the genes are restricted to this single species of mosquito.

It is important to note that mosquitos can only fly about 200 yards and the offspring die. So the effect is extremely localised. Potential effects of Oxitec OX513A mosquitos only affect the area in which they are released.

We have been asked whether, if this approach was adopted widely, the food chain could be affected. In the Florida Keys, the non-native Aedes aegypti mosquito makes up less than 1% of local mosquito biomass, and is not an important food source for predators; in fact there is nothing that is depends on it as it is a non-native species.

By contrast, the use of insecticides is less discriminating. Insecticide sprays can kill many species and will impact the diversity of insect life and dependent species. By targeting only the key insect species capable of disease transmission we believe that insecticide spraying can be reduced, to help protect biodiversity in the area.

Further reading:

Nordin, M.O., Donald, W., Ming, H.W., Ney, G.T., Mohamed, A.K., Halim, A.A.N., Winskill, P., Hadi, A.H., Lacroix, R., Scaife, S., et al. (2012). Oral ingestion of transgenic RIDL Ae. aegypti larvae has no negative effect on two predator Toxorhynchites species. PLoS One 8.

Fang J (2010) Ecology: A world without mosquitos. Nature 466, 432-434.

Spielman, A., and D’Antonio. M. (2001) Mosquito: The Story of Mans Deadliest Foe, Hyperion, New York.

Could you eradicate Aedes aegypti? (Q12)

A goal of this trial is to demonstrate the ability to control the local non-native Aedes aegypti population. Eradication of a species using this technique, we believe, is not possible or practical.

Further reading:

Fang, J. (2010). A world without mosquitos. Nature 466: 432-434.

Is the Oxitec mosquito harmful to humans or animals? (Q4,7,12)

No. The inserted genes (color marker and self-limiting genes) are not toxic or allergenic. The gene that prevents the offspring from surviving to adulthood affects only those mosquitos that inherit it, and works by causing subtle adjustments to the insect cells, rather than being toxic.

Also, if any other insect bird or fish were to eat a GM mosquito this would be no different to ingesting a wild mosquito. They would obtain nutritional elements – protein, fat, carbohydrate and others – as they would from eating any mosquito.

Independent studies as part of the regulatory approval process showed that OX513A had no effect on arthropods/fish in feeding studies compared to non-GM Aedes aegypti, when they were fed artificially high levels in their diet, much higher than they would ever eat in the wild.

To date more than 90 million Oxitec mosquitos have been released worldwide in different countries and there have been no reports of adverse impacts.

Further reading:

Nordin, M.O., Donald, W., Ming, H.W., Ney, G.T., Mohamed, A.K., Halim, A.A.N., Winskill, P., Hadi, A.H., Lacroix, R., Scaife, S., et al. (2012). Oral ingestion of transgenic RIDL Ae. aegypti larvae has no negative effect on two predator Toxorhynchites species. PLoS One 8.

http://www.ctnbio.gov.br/index.php/content/view/19523.html

Do you release male and female mosquitos?

Oxitec releases virtually all males. We sort the males from the females as pupae and have a greater than 99.9% sorting efficiency. But inevitably we will release some females but this is negligible compared to the number of wild females taken out of the environment through our approach. For, instance, in the recent trial in Panama the wild Aedes aegypti population was reduced by over 90%. During the Panama trial the number of female Oxitec mosquitos released was equivalent to less than one per person per year.

Further reading:

Harris, A.F., McKemey, A.R., Nimmo, D., Curtis, Z., Black, I., Morgan, S.A., Oviedo, M.N., Lacroix, R., Naish, N., Morrison, N.I., et al. (2012). Successful suppression of a field mosquito population by sustained release of engineered male mosquitos. Nat Biotech. 30, 828-830.

Carvalho, D.O., Nimmo, D., Naish, N., McKemey, A.R., Gray, P., Wilke A.B.B., Marrelli, M.T., Virginio, J.F., Alphey, L., Capurro, M.L. 2014. Mass Production of Genetically Modified Aedes aegypti for Field Releases in Brazil. Journal of Visualised Experiments 83 http://www.jove.com/video/3579/mass-production-genetically-modified-aedes-aegypti-for-field-releases

What would happen if a person or animal got bitten by an Oxitec mosquito? (Q4,7)

The bite of an Oxitec female mosquito is the same as a wild one because the proteins of the two introduced genes (self-limiting gene and color marker) are non-toxic and non-allergenic. A study carried out by the National Institute of Health, USA has shown that the protein from the self-limiting gene is not present in the female mosquito’s saliva. Also, it should be noted that the likelihood of a bite is extremely unlikely. During the most recent trial in Panama the number of female Oxitec mosquitos released was equivalent to less than one per person per year.

If the trial goes ahead how many mosquitos would be released?

The number is determined during the trial. There are about 1000 mosquitos released per pot, and the number of pots and release sites is adjusted during the trial based on local conditions which change. There would be about 3 releases per week, and the males disperse quickly.

In Cayman, 3.3 million mosquitos were released during that 6 month trial, which resulted in more than 90% suppression of the target aegypti population. In Panama, a similar sized trial, that worked out to a release of less than 5,000 mosquitos per person across the entire 6 month trial to achieve suppression of the local Aedes aegypti population by over 90%.

Further reading:

Harris, A.F., McKemey, A.R., Nimmo, D., Curtis, Z., Black, I., Morgan, S.A., Oviedo, M.N., Lacroix, R., Naish, N., Morrison, N.I., et al. (2012). Successful suppression of a field mosquito population by sustained release of engineered male mosquitos. Nat Biotech. 30, 828-830.

What are the criteria for success or failure?

In the Florida trial the criteria for success would be that the Oxitec mosquito mates with the local Aedes aegypti mosquitos, passes on the color marker and self-limiting genes to their offspring, and that this brings about a reduction in the local pest Aedes aegypti population in the release area.

What is involved in a release, will it be a nuisance?

Past projects have shown that it should not be a nuisance to residents. We release the male mosquitos in pots of about 1000 mosquitos and the males disperse very quickly. They fly off in search of mates and within a few minutes there is no visible sign of a release having taken place.

What is the lifespan of male and female mosquitos? (Q5,10)

The average lifespan of wild Aedes aegypti male mosquitos is around 4-7 days. Oxitec mosquitos tend to live less long. The average lifespan of wild Aedes aegypti female mosquitos is up to four weeks depending on environmental factors such as temperature.

What would happen if the trial didn’t go ahead?

FKMCD would continue to search for new tools in the fight against disease carrying mosquitos because current control methods are insufficient to lower the Aedes aegypti population enough to definitively prevent a future outbreak of dengue or chikungunya. Oxitec’s work in other countries would continue.

Did Oxitec take DNA from other organisms and put it into the Oxitec mosquito? (Q1,6)

Oxitec uses genes optimised for expression in insects to deliver the technical effect needed. The genes themselves are synthetically manufactured but the inspiration is based on working systems found in organisms from nature, from which sequences are available in DNA databases. Oxitec uses these databases as a starting point and then adjusts the sequence to specifically work in insects. The final genes share little similarity to the DNA from the organisms from which they were derived. Some elements are commonly used, for example, synthetic DNA from the “tet-off” system is the basis of the self-limiting gene, and has also been used extensively and safely in many other biological systems.

Further reading:

/understanding-oxitec-science

www.tet-systems.com

How do you rear mosquitos if the offspring die?

In a production facility, the larvae are given an antidote in their rearing water from the tetracycline family which inactivates the self-limiting gene. This enables us to rear large numbers of mosquitos. Those that are released cannot access this antidote in the right quantities and/or at the right time and so the self-limiting gene works effectively, as demonstrated by field trials in different countries.

What happens if the Oxitec mosquitos find the antidote in the environment? (Q4,7,9)

That would be extremely unlikely. Aedes aegypti breed in fresh still water and avoid polluted or running waters. So they avoid pools where there is effluent or run-off from farms or water treatment plants that could contain tetracycline, from human or animal therapeutic treatments. But even if tetracycline were in a water source, in which Oxitec mosquitos laid their eggs, it would need to be at a high enough dose for it to function as an antidote. Studies have shown sufficient doses have not been found in the environment. Also, tetracycline rapidly degrades in the environment due to factors such as sunlight and microbial communities.

But hypothetically, what would happen if there was a source of tetracycline in the environment in exactly the right dose and condition to act as an antidote? Theoretically they could reproduce in that water but offspring moving away from the source would still die. As we monitor throughout the trial the color marker means that this would be easily identifiable. If desired, the area could be treated with other mosquito control methods such as insecticides, before recommencing with Oxitec release.

Further Reading:

Duff, B. (2005). Presence of tetracycline antibiotics in surface water. A study of the presence/ absence of tetracycline in the Raccoon river watershed, Des Moines water works laboratory.

Gulkowska, A., Y. He, et al. (2007). “The occurrence of selected antibiotics in Hong Kong coastal waters.” Mar Pollut Bull 54(8): 1287-1293.

Le-Minh, N., S. J. Khan, et al. (2010). “Fate of anitbiotics during municipal water recycling treatment processes.” Water Research 44: 4295-4323.

Locatelli, M. A. F., F. F. Sodre, et al. (2011). “Detemination of Antibiotics in Brazilian Surface Waters Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.” Arch Environ Contam Toxicol 60: 385-393.

McQuillan, D., S. Hopkins, et al. (2002). Drug Residues in Ambient Water: Initial Surveillance in New Mexico, USA. 7th Annual New Mexico Environmental Health Conference.

Could the Oxitec mosquitos develop resistance to the antidote? (Q4,9)

That would be extremely unlikely. Our modified mosquitos reared in the production facility require the antidote to stay alive, so there’s no selection pressure for them to develop resistance to the self-limiting gene we’ve introduced. As a result, we’ve not observed any sign of resistance developing in our mosquitos, despite rearing them in large numbers over more than 150 generations. It’s worth noting that the Oxitec mosquitos are the same as wild ones except that they cannot reproduce effectively. If for whatever reasons the self-limiting gene does not work then the result is that the mosquitos would be the same as wild ones. There is no negative over and above the wild equivalent. So we would stop releases. Furthermore, the color marker means that if any resistance developed we would see it in the field, and could address it with other methods such as the application of pesticides which OX513A is susceptible to.

Will there be vast quantities of tetracycline waste produced by the rearing facility? (Q4,7)

No. The amount of tetracycline antidote given mosquito larvae so they can survive to adulthood for controlled release is insignificant compared to usage for pets, farming, and human therapeutic use.

Just considering use by people for context – the amount of tetracycline in waste water at the mosquito rearing facility in Florida would be 140 times lower than the average of amount of tetracycline entering waste water in Florida Keys through human therapeutic use alone. Another way to think about it is that, per day, our tetracycline waste (~200 mg) would be less than what one person excretes when they’re on a standard daily tetracycline dose (2x 500 mg).

Do some of the Oxitec mosquitos survive? (Q4)

In the laboratory, under optimum conditions for the mosquitos, a small number of Oxitec larvae (up to 5%) have been observed to survive until adulthood when they are in highly favourable conditions (for the mosquito) of ideal and constant temperature, adequate food supply, and no predators. But in the open environment, there are very few survivors, and these will quickly disappear from the population.

Further Reading:

Phuc, H.K., Andreasen, M.H., Burton, R.S., Vass, C., Epton, M.J., Pape, G., Fu, G., Condon, K.C., Scaife, S., Donnelly, C.A., et al. (2007). Late-acting dominant lethal genetic systems and mosquito control. BMC biology 5, 11.

Harris, A.F., McKemey, A.R., Nimmo, D., Curtis, Z., Black, I., Morgan, S.A., Oviedo, M.N., Lacroix, R., Naish, N., Morrison, N.I., et al. (2012). Successful suppression of a field mosquito population by sustained release of engineered male mosquitos. Nat Biotech. 30, 828-830.

Who is regulating the Florida trial? (Q2)

The Food and Drug Administration Center for Veterinary Medicine (FDA-CVM) is the lead agency coordinating other federal and state agencies such as Center for Disease Control (CDC), Environmental Protection Agency (EPA) and US Department of Agriculture (USDA).

Why is the Oxitec mosquito being regulated as an ‘animal drug’, is it a loophole? (Q2,4)

No, there’s no loophole – Oxitec is required to work with the regulatory bodies of each country and that country decides according to its laws and regulation how the process will work. In 1986 the US Office and Science Technology Policy published the Co-ordinated Framework for Harmonisation in Biotechnology, which directs the evaluation of products of biotechnology to take place under existing statutes and laws.

The Food and Drug Administration Center for Veterinary Medicine (FDA-CVM) have jurisdiction to regulate the Oxitec mosquito under the Federal Food Drug and Cosmetic Act (FFDCA) as the genetic construct affects “the structure and function” of the mosquito. For the proposed Florida trial they are conducting a multi-agency review, which includes other agencies such as (Centers for Disease Control) CDC and the Environmental Protection Agency (EPA) as well as liaison with Florida state regulators.

In Brazil, the national biosafety regulatory body was CTNBio (National Technical Commission for Biosecurity). They approved the Oxitec mosquito for commercialisation after evaluating OX513A for safety to human, animal and environmental health based on a technical dossier with study and trial results. Their risk assessment is published online: https://bch.cbd.int/database/record.shtml?documentid=105831

Does the public get to see the information the FDA and other agencies review? (Q2)

As part of the regulatory process the agency (FDA-CVM) has to comply with the National Environmental Protection Act, where agency actions – such as approving the trial release, are examined for their environmental consequences. Part of this process involves public consultation on key information.

Further reading:

NEPA – A Citizen’s Guide: https://ceq.doe.gov/nepa/Citizens_Guide_Dec07.pdf

When will FDA make a decision? (Q2)

There is no fixed timeline as such. FDA are conducting an independent review involving multiple agencies and experts. This is an interactive process as they can and do seek further explanations, involve experts, ask for more data, review processes, inspect facilities, etc. Only when they are fully satisfied with all aspects can the trial go ahead.

What would Oxitec do if there was a problem? (Q4,7,12)

We would stop releases. A key aspect of this controlled approach is monitoring, which is intensively conducted thought the trial. The color marker in all our insects and in their offspring facilitates this monitoring control of the insects and releases can be stopped at any time. It should be noted that the stringent regulatory review is designed to anticipate all identifiable risks, their likely occurrence and potential impact along with any mitigation measures that might be required to minimise that impact. If there are significant unanswered questions on safety it is unlikely that any agency would allow release.

What are the results for mosquito control? (Q7,12)

In all trials to date we have shown that the local Aedes aegypti population has been reduced by over 90%. This is a level of control significantly greater than can be achieved with insecticides (typically 30%; Ballenger-Browning & Elder 2009) and one where we consider the environmental impact to be much lighter. According to FKMCD they expect they can control up to 50% with currently available methods including insecticides and that if they used the Oxitec approach in the future, they could significantly reduce the volume and incidence of insecticide spraying.

Further reading:

Ballenger-Browning K.K, Elder J.P., (2009) Multi-modal Aedes aegypti mosquito reduction interventions and dengue fever prevention. Tropical Medicine and international health 14(12): 1542-1551.

http://keysmosquito.org/question-answers-on-gm-mosquitos/

Are there studies of disease control yet? (Q12)

No – but this also applies to all methods of controlling mosquitos, whether insecticides, traps or other approaches. To monitor the actual impact of any mosquito control method on disease is extremely complex and likely to require multi-year trials and large numbers of people.

The recommended method of reducing the likelihood of disease is not in doubt. The World Health Organisation (WHO) states ‘At present, the only method to control or prevent the transmission of dengue virus is to combat the vector’.

However it is in everyone’s interest that practical ways to evaluate and measure the impact of mosquito control are found. Oxitec is working with the WHO Vector Control Advisory Group to determine what sorts of epidemiological studies could be possible.

Some models do exist and some academics have done work to try to estimate what level of Aedes mosquito population one needs to spread or maintain dengue in circulation. Excellent work in this area has been done by Dana Focks (USA) and Lee Han Lim (Malaysia). In each of our trials we have reduced the Aedes aegypti population by over 90% which according to the Focks model would take the mosquito population well below the disease transmission threshold. However we would stress that this is a model – not proof. So for the moment our key metrics are all entomological ones.

Further reading:

Focks D et al. Transmission thresholds for dengue in terms of Aedes aegypti pupae per person with discussion of their utility in source reduction efforts. American Journal of Tropical Medicine and Hygiene, 2000, 62(1):11–18.

Could there be unforeseen consequences? (Q4,7)

The Oxitec mosquito has been evaluated for over 10 years in a variety of studies and trials in many different situations. From these promising results we are confident that any use of the Oxitec mosquito will have minimal impacts. There, of course, remains a small possibility, as with any new technology, that sometime in the future there may be unforeseen consequences. Unforeseen consequences could, of course, be positive as well as not positive. But the potential for unforeseen consequences has to be balanced against the benefits a technology can bring.

Our approach when compared to say insecticides has some very unique points that we believe make it highly preferable in addition to the results seen to date in other countries.

First, it is highly targeted to the one insect species that causes harm to humans. Other insect life is untouched.
Second, the approach works by ensuring that females that mate with Oxitec males do not reproduce – the insects die and their offspring die – so there is no spreading effect or persistence in the environment.
Third, all the males released and their offspring (which will die) contain a color marker so we can monitor them in the environment. We can determine where they go, how long they live and how effective they are.
Further Reading:

http://www.nytimes.com/roomfordebate/2015/02/23/can-genetically-modified-mosquitos-eliminate-dengue-fever

What is Wolbachia and are you working on this?

Wolbachia are bacteria that live within insect cells and are passed from one generation to the next through the insect’s eggs. Wolbachia is present in up to 60% of all the different species of insects. However Wolbachia is not naturally occurring in Aedes aegypti. Some academic groups have engineered Aedes aegypti strains to carry Wolbachia. The hypothesis is that Wolbachia infected Aedes aegypti are less able to transmit dengue than naturally occurring Aedes aegypti. To be effective the plan is that the Wolbachia-infected mosquitos are released into the environment with the intention that, in time, they will spread and replace the naturally present species. Trials are being carried out in a number of countries.

Oxitec does not work on Wolbachia infected mosquitos.

Further reading:

http://www.eliminatedengue.com/program

Would the trial results be made available?

Yes, we will work within the process established by the FDA and will share the results as we have done with all trials to date.

Do Oxitec employees have ownership in the company? (Q3)

Oxitec is wholly owned by a US public company called Intrexon (NYSE: XON). In common with many companies Intrexon operates a stock option scheme in which some employees may choose to participate, and this is disclosed under SEC requirements. As a publicly traded company, Intrexon is subject to a number of rules and regulations, one of which is the implementation of a Code of Business Conduct and Ethics. Intrexon’s Code includes, among other things, an obligation that its employees comply with all laws where they operate, as well as a responsibility to be good corporate citizens in these communities. Additional information can be found here http://investors.dna.com/corporate.

Where can I get more information? (Q11)

Oxitec scientists publish data in peer reviewed journals. Information pertaining to our products, and regulatory reviews of their safety are available on public websites. Here’s a link to our publications: /category/publications/.

Further reading:

http://keysmosquito.org/question-answers-on-gm-mosquitos/

Latest GM Mosquito Information

GM Mosquito Surveys

/category/publications/

Questions from Key West Town Hall Meeting

1. What genes are the mosquitos modified with?
2. Has FDA approved trial? If not, when will they make decision?
3. Does Derric or Andy have any ownership in Oxitec?
4. What is the risk of using genetically engineered Aedes aegypti? Is there a risk assessment?
5. How long do the genetically modified offspring live?
6. How has Oxitec engineered the mosquitos? Are they genetically modified? If yes, what other organisms’ DNA is involved in the engineering?
7. What impact does the genetically modified mosquito have on the environment?
8. Do you know what effect this has on birds?
9. Do you know if the antibiotics will become less effective and will different types be used?
10. What is the life span of the female mosquito?
11. Where are peer review studies published?
12. Do these studies include long term environmental effects on insects, mosquito populations and dengue rates of infections?: