- We implemented a different insecticide than originally planned based on biosafety and biosecurity concerns raised in an expert discussion.
- Our communication in wiki, registry, personal, and on social media is driven by advice on biosecurity from experts.
- We integrated the S.H.I.E.L.D. hardware elements such as the self-healing hydrogel and the NDR-70 sealing rings based on interviews with mosquito researchers.
- We decided where to place the S.H.I.E.L.D. based on advice by international experts.
- We focussed on the application of the S.H.I.E.L.D. against other insect related threats.
Our project deals with the issue of fighting malaria-transmitting vectors, for example Anopheles gambiae. With the S.H.I.E.L.D. we have developed a novel malaria prevention method which contains engineered bacteria to lure and kill mosquitoes. We are aware that working with GMOs and keeping them in a device in the field implies a lot of different aspects to think about. Therefore, we talked to both national and international experts working in malaria research and biosafety. With the help of their expertise we were able to further improve design and safety of our project enabling it to fulfil its purpose of safely and sustainably combating malaria.
Integrated Human Practices
Before starting with the practical implementation in the lab we met biosafety expert Dr. Mirko Himmel. A biochemist by training, he currently works at the Carl Friedrich von Weizäcker-Centre for Science and Peace Research, where he specializes in biological arms control and biosecurity matters. He introduced us to the problem of Dual Use and Dual Use Research of Concern (DURC). After his presentation we discussed safety- and security-relevant aspects of our project. One major topic was the insect toxin we had originally chosen as kill mechanisms of the S.H.I.E.L.D. When asked by Dr. Himmel about its properties, it became obvious that the data available was not sufficient to ensure the safe usage in our trap. Published data indicated a low toxicity to mammals, which outside the field of bioinsecticide research can be interpreted as very toxic in realistic doses.
Since the toxin might prove to be harmful to humans and other mammals we decided to use an alternative insecticide which was known to be exclusively toxic to insects, BjaIT, which we submitted as BBa_K2588019. BjaIT inhibits voltage-gated sodium channels of insects exclusively while not being able to bind to mammalian sodium channels.
We are fully aware of the dual use potential sustained production of a toxin raises. We discussed how to deal with information on toxin-producing and -secreting bacteria with both Dr. Mirko Himmel and Piers Millett, iGEM Director of Safety and Security. Together, we decided to publish all results in wiki and registry, but not to release details on the different toxins, production methods, and experimental and design workflows, increasing the effort people with possible harmful intent would have to take to recreate our experiments with possibly more harmful agents.
With Dr. Mirko Himmel, we discussed the danger of unintentionally releasing the GMOs used in the S.H.I.E.L.D. Two different aspects must be considered:
We had to make sure that the trap is robust in order to prevent breakage or leaks under intended use stresses as well as stronger environmental influences and forces. Therefore, we decided to use a very hard, durable, UV resistant, autoclavable plastic employing strong sealing rings to ensure the S.H.I.E.L.D. is not easily damaged, releasing GMOs in the process.
On the other hand, in the unlikely case that GMOs are released into the environment, they must not be able to spread uncontrollably. While the implemented growth inhibition module BBa_K2588021 ensures that the modified bacteria would not be able to proliferate even under ideal circumstances, we would suggest to introduce a kill switch, such as the Amber substitution kill switch introduced by iGEM Darmstadt 2016 into the organism before using the S.H.I.E.L.D. in the field. A stop codon (Amber codon) is introduced at the beginning of a gene coding for a transcription factor, which under desired conditions inhibits the expression of a lethal gene. A special amino acid that do not naturally occur in E. coli corresponds to the amber codon for the gene to be elongated past the stop signal. In the S.H.I.E.L.D. this amino acid would be provided by the cyanobacteria. In the environment, E. coli would no longer be provided with it, causing the production of the transcription factor to cease. Therefore, the activation of the lethal gene would ensure the death of E. coli cells outside of the trap. Since genetically altered E. coli are only able to survive in the environment as a symbiosis with cyanobacteria and the survival of those in African climatic conditions is highly unlikely, Dr. Himmel agreed this would be a feasible approach to ensure our traps biosafety.
We strongly suggest to implement this feature to anyone deciding to further develop our project before applying it for registration. However, the limited time available in an iGEM period did not allow us to implement the complete iGEM Darmstadt 2016 project.
With Dr. Mirko Himmel, we raised two additional questions we could not find sufficient answers to: Could diseases be spread between mosquitoes landing on the S.H.I.E.L.D., and could mosquitoes develop resistances against the toxin we employ?
To gain more knowledge about malaria-transmitting vectors like Anopheles gambiae, and to answer some of our questions regarding new and existing mosquito traps, we interviewed Dr. Thomas Jacobs from the Bernhard Nocht Institute for Tropical Medicine, who currently works on the topic “Protective and pathogenetic role of T-cells in murine malaria.”
From the mosquito expert we learned that female mosquitoes are fed with blood in the lab using a bowl with pre-warmed blood which is covered with parafilm for mosquitoes to land on and sting through. During this process, the parafilm gets destroyed irreversibly. With our focus on sustainability, this approach would not be feasible for use in the S.H.I.E.L.D. To accomodate mosquitoes landing and taking up the insecticide, we implemented a self-healing hydrogel. However, we worried bacteria could grow on the hydrogel surface, possibly infecting the landing mosquitoes or being distributed by them. When told about the S.H.I.E.L.D.’s approach, Dr. Jacobs assessed transfer of pathogens between landing mosquitoes to be very unlikely because even under laboratory circumstances the infection of mosquitoes is quite hard to achieve, and pathogens would not be able to survive for on the hydrogel for longer times. Since we are aware of insecticide resistances being an abundant problem in fighting malaria, we discussed how likely a novel resistance to our toxin could occur. In his opinion, this should not be a major problem as long as the dose of our toxin is high enough to kill the mosquitoes swiftly enough to prevent them from developing a resistance. Even if a resistance to the toxin should occur, the modular BioBrick system would allow a relatively easy substitution with another insecticide.
We also met with the Deutsche Malaria GmbH and most importantly their managing director Dr. David Hutchinson, who started working as a clinician on tropical medicine in 1971. He suggested to use the S.H.I.E.L.D. to fight mosquitoes transmitting dengue virus as well as malaria. This led to further consideration to use the S.H.I.E.L.D. to fight other threats caused by insects. Apart from mosquitoes we could target different vermins through modulation of the S.H.I.E.L.D.
We sought to gain insights from malaria and mosquito experts from malaria risk regions in which the S.H.I.E.L.D. would be used. Working in Hamburg, Germany, we could not guarantee to not miss details and technical requirements that apply in malaria risk regions in warmer climates, and environments we are not used to.
We interviewed multiple experts from Uganda and Tanzania, countries in which malaria still threatens many people despite significant efforts towards malaria elimination. With the help of iGEM Makerere, we reached out to local experts with different professional backgrounds to get an assessment of the feasibility of our project in Africa. We designed an open questionnaire for them, answering both specific questions and leaving room for advice they would like to give us moving forward with our project. From their answers we gained valuable insights on characteristics important for both the technological feasibility, and the social acceptance for people working and living with the S.H.I.E.L.D.
First and most importantly, it is beneficial to use long-maintenance devices for malaria prevention. Many preventive measures against malaria are not maintained properly due to the financial strain this puts on the population. Once placed, our self-sustaining trap would minimize this problem as well as problems caused by lacking infrastructure in rural areas. Beyond that, the main problem for people living in affected areas is that using repellents, insecticides or other precautionary methods like bed nets has an great impact of their daily life. Since people are inconvenienced by some of the necessary precautions compliance with them is oftentimes problematic. While we strongly encourage the continued use of bed nets and other available safety measures, with the S.H.I.E.L.D. we aim to provide an additional appliance that will place no further strain on the people’s comfort.
Another strong advocate of a multi-pronged approach to combating malaria we had the pleasure to talk to is Dr. Andrew Hammond, one of the leading researchers in the field of malaria control through genetic based technologies. He is postdoctoral researcher at the Imperial College in London. Dr. Andrew Hammond helped pushing our project further by sharing his expertise on project development and legislature with us. He especially gave us a lot of suggestions regarding the experimental design, for example in conducting mosquito experiments and testing odour baits. We got an overview of possible locations for the S.H.I.E.L.D. to be placed for maximal impact. Specifically close to possible breeding sites, such as stagnant freshwater, close to bushes and on the outside of houses by eaves are optimal locations to ensure mosquitoes are eliminated before they get in contact with residents. The latter would allow us to use the natural odours that emanate from households through the eaves to lure in the mosquitoes in addition to our bait system, and eliminating them with our trap before they actually enter the houses.
We would like to thank everyone who gave us their priceless input in order to help us improve our project and its implementation even further.
Student Research Center Hamburg
Since we know how important it is to spark interests at an early age, we wanted to promote knowledge about life sciences and synthetic biology, as well as share our passion for science in general. What better place to do so than Hamburg’s Student Research Center (Schülerforschungszentrum, SFZ)?
Founded in 2017, the Student Research Center is a relatively young institution that gives students of all ages from different schools the chance to work on their individual research projects in their free time. Since the biology and biochemistry lab is not ready yet, we had the opportunity to advise how to equip the lab. We have also planned project days for students once the lab is fully equipped.
We were delighted to give a presentation on synthetic biology, iGEM and our project on the first ever Pizza Friday, an event where all students and advisors working at the SFZ come together to exchange information about their projects. Afterwards, we had a lively discussion with the students. In the long-term, we are available as mentors to students doing research at the SFZ and to help with questions they might have about their projects.
Who knows, with our help there might even be an iGEM Hamburg high school team in a couple of years.
Discussion with Deutsche Malaria Gesellschaft
To introduce ourselves, get expertise on the S.H.I.E.L.D. and discuss further cooperation with the Deutsche Malaria GmbH we met with Dr. David Hutchinson, Erik Lindemann and Frank Oertel. Dr. David Hutchinson is an expert with more than 50 years of experience in the field of tropical medicine mainly working on malaria treatments as a clinical research clinician. Erik Lindemann and Frank Oertel offered us their expertise in funding and development to build a commercial product.
After explaining our idea, we discussed the practical application of the S.H.I.E.L.D and the future challenges for a broad implementation. When explaining their vision in joint fight against malaria, Mr. Oertel mentioned the frightening numbers and put our focus on the high child mortality rate.
Mr. Oertel: “We think the need to fight malaria is getting more relevant. There are about 500.000 deaths and 200 million infections due to malaria and 80 percent of these deaths are children below an age of five.”
At the end of our discussion Dr. David Hutchinson drew our attention to another important topic, we had not investigated at that time.
Dr. Hutchinson: “But out there is a huge disease, causing immense morbidity, insect vector borne disease, which is dengue. That is a crippling disease. […] Very seriously, you should bare that in mind.”
The S.H.I.E.L.D. uses as a device to fight other insect borne diseases shows its great potential as a protection against today’s biggest health risks.
Bjarne: We started our project and developed it and the basic problem we saw is that in Africa in many rural areas you do not have a very good infrastructure like hospitals and electricity. So, we asked ourselves: How can we design something that is everlasting and can actively fight malaria mosquitoes and we came up with this idea of a co-culture between cyanobacteria and genetically engineered E. coli. The plan is that the cyanobacteria produce nutrients for the genetically engineered E. coli, while the E. coli have to do the majority of the work and produce certain molecules, certain proteins, that we can use to basically lure mosquitoes and kill them.
Dr. Hutchinson: The killing part is the interesting one.
Bjarne: That is why we firstly designed pathways to produce certain volatile molecules that lured these mosquitoes so that they get to our trap and then we designed a specific insecticide from a scorpion, that only targets insects and which is able to kill these mosquitoes. Also the E. coli are genetically engineered so that they have limited growth, because otherwise they would simply overgrow and also it improves the trap’s biosafety, since these E. coli are not able to reproduce in a normal environment and also they are not able to exit these traps, because we have a membrane with a distinctive size, so these small molecules and small proteins, the E. coli produce, are still able to exit the trap.
Dr. Hutchinson: May I ask you: Is this mosquito-specific?
Bjarne: The papers this is based on were written about Anopheles gambiae. They tested different kind of luring assembles in order to lure these mosquitoes.
Dr. Hutchinson: And does it kill the mosquito at the time or does the mosquito then fly away?
Oda: Fly away and then die.
Dr. Hutchinson: They will fly away? They will die on their own?
Dr. Hutchinson: Because I belong to the mosquito protection society.
Mr. Lindemann: Do they only kill those mosquitoes that carry the malaria parasite?
Lisa: No, it’s mosquitoes in general.
Bjarne: What I also wanted to say: We haven’t had a chance to test it, so we don’t know whether they fly away or not, but that’s the plan so far. And also, these proteins are not that deathly, that they kill them right away, but we don’t know yet.
Alex: But there is also a kind of aspect of mosquito protection. So, there is an alternative idea, which is called gene drive and with the gene drive technology … You are familiar with it?
Dr. Hutchinson: Yes.
Alex: The gene drive technology would lead to the extinction of these mosquitoes. So, our trap will reduce the population of mosquitoes in a specific place. But we are not aiming at killing them all.
Lisa: We don’t want them to go extinct. Just in the places where you put the trap the mosquitoes are killed, but some miles away they won’t get hurt.
Dr. Hutchinson: So perhaps you would use this in the villages, but not in the forests. Just to make sure again: I’m so sorry about this English. So please talk in German, if you wish. I’m not offended. So again, I understand that you would be killing all mosquitoes within an environment, whether these mosquitoes are transmitters of malaria or not.
Bjarne: What we know is that there are basically three kinds of mosquitoes, that mainly target humans or specifically target humans. The molecules we produce or the enzymes we use are partly from skin microbiota, so we try to imitate human skin or human scent to target certain malaria mosquitoes. And I also think there is this study showing that mosquitoes with plasmodium are even more attracted to humans than others.
Dr. Hutchinson: Yes.
Bjarne: So yes, we would have off-target effects, but we try to minimize them.
Mr. Oertel: So, your trap is kind of a virtual net? It will protect people where the trap is placed.
Bjarne: Yeah. You can imagine them like a giant attractor like a black hole for mosquitoes. You place them and try to get as many mosquitoes in a local area.
Dr. Hutchinson: The trap of course has to be preferential to the mosquito compared to the human being. You have got to make it more attractive.
Mr. Oertel: Do you plan to place it in a house?
Lisa: No, it needs to stay in the sun, because of the cyanobacteria. They need sunlight to grow and produce glucose for the E. coli. It’s not possible to place it inside.
Bjarne: There are other traps that have a similar mechanism, so there are traps that lure mosquitoes and try to kill them. The problem is that they need maintaining, they need electricity and our trap should work as follows: You put them down and it stays there, it is sustainable, it keeps working. But that is why we have some information on how to set up your trap, because if you use these kind of traps that lure and kill you usually not put them inside a house, because you might have the mosquitoes going into the house, because they scent the trap, and they end up stinging the human. So, you put them around certain areas to get the mosquitoes away.
Dr. Hutchinson: Do you have an insectarium here?
Bjarne: We work with the Bernhard-Nocht-institute. Working with the mosquitoes is just possible at the Bernhard Nocht Institute for Tropical Medicine.
[They asked about our trap and we showed them the prototype and pictures. We also repeated the basic idea in German to Mr. Oertel and Mr. Lindemann and talked about the patent and possible collaborations with the DMG.]
Mr. Oertel (translated): We think the need to fight malaria is getting more relevant. There are about 500.000 deaths and 200 million[malaria infections and 80 percent of these deaths are children below an age of five. That is mainly due to too strong medication needed for proper treatment of malaria. The new therapy we develop focusses on a fosmidomycin, a medication that can be used for treatment of children. That is why we thought our ideas fit together and I thought about something like a virtual net. Bill Gates contributed thousands of nets across Africa to fight malaria, but unfortunately these nets ended up in the environment e.g. used as fishing nets and due to their size also fished way to young fishes. They help a lot if used properly, but a virtual net, which would be my spontaneous idea, that consists of a triplet of approaches could work.
Oda (translated): But also, we need to test the reach of the traps. There are just some things we can not anticipate yet.
Mr. Oertel (translated): No, no but this would be something you could work towards. For me the title should be virtual net, but I do not know if that fits your ideas.
Alex (translated): This is the potential. The deciding tests will be carried out at the Bernhard Nocht Institute and depending on the results we will develop our project.
Bjarne (translated): Also, we hope to contribute to the fight against malaria like you mentioned in your vision. One can easily forget, that there are so many lives on the line and you can really make a change, save lives, change lives.
Mr. Oertel (translated): We also like the practical approach. You can always research more and spend more money like the Bill Gates Foundation does, but in the end, they spend a lot money on artemisinin and similar therapies. The big danger are upcoming resistances in Africa. That already happened in Asia, even in London three people died coming back from their travels and they could not be saved using special artemisinin based therapies. If that happens in Africa, the results would be devastating. Now there are Chinese workers coming over, as the Chinese have invested a lot in Africa and build up infrastructure and they could bring along the resistant malaria strains. This problem has not been a topic in the public, but it is there. Now the people start to think what is next, what do we do now to fight malaria. Fosmidomycin can offer an alternative that already had successful clinical trials. We can work out a proper therapy, that works even when artemisinin does not. So, we also have practical approach, that simply helps. But you have an approach that is not just theoretical, sure you still have to figure some things out, what is normal for every company and every startup, but it is something you can grasp. My question is if we do not fund this project, what happens next? Then you just had a good idea and all around the world people have good ideas. But sometimes you have to follow up on your idea and develop it into a relevant application. That is something we could coach and help.
Oda (translated): That are some skills not everybody has.
[We talked about the patent and the possible financial support of our project with Mr. Oertel and Mr. Lindemann]
Dr. Hutchinson: It seem putting a commercial hat, although I am a clinician, this could have tremendous utility, if in fact it really is preferential, that mosquitoes prefer that trap over human skin. It could provide personal protection. They have been telling you about Deutsche Malaria Gesellschaft and what we are up to? Yes? And how possibly the two elements of all this, what you do and what we do, could possibly complement one another. He has been telling you that? I have to check up on him. [chuckle] He may not get it right and I do not know. Thank you.
[We talked about a future collaboration, formalities and Dr. Hutchinson showed us photographs from Africa showing areas, institutes and people working and affected by malaria]
Dr. Hutchinson: Europeans seem to forget about South America.
Bjarne: We talked with a person from Brazil about it. It was also in the context of the competition. He was a so called iGEM Ambassador working on the competition and he was from Brazil and we talked with him in Marburg at an iGEM meetup. But he did not have specific contacts connected to malaria. We talked about possible application not just in Africa, but also in South America. We always just hear about Zika virus coming up, but there are possible other applications of our trap.
Dr. Hutchinson: And thinking about this, while you were talking in German, I mean this is in the same category as impregnated nets in a way. It is in the same sort of business and I do not know impregnated net people. It is kind of all in the same area. They are very active.
Mr. Lindemann: A certain aspect of this is of course the financing of everything. We know the organizations, which are able to finance projects like this. The other aspect is as David mentioned are field studies, getting in the touch with people, who can conduct these studies, and get approvals and so on. Could be a fitful collaboration between our two organizations.
Dr. Hutchinson: So often, as in everything, it is who you know.
Dr. Oertel: And make the process efficient. You probably have some other things to do.
Dr. Hutchinson: Can you do evaluation here with the Bernhard Nocht Institute? I do not know and have no dimension. Do you put it in this room and release a load of mosquitoes and see what happens? Is that what you are doing?
[We showed them our planned mosquito experiments and as Mr. Oertel had to go earlier we finalized on the details concerning our cooperation]
Dr. Hutchinson: As follows: Malaria has understandably a lot of emotion behind it, because we hear all about these dying African children, so many per minute. And we multiply that into hours and days and all the rest of it and that is all of course very understandable, but there is out there a huge disease, causing immense morbidity, insect vector borne disease, which is dengue. That is a crippling disease. Not so much associated with mortality and hence the emotion, that goes with it. But it is a real, real problem. So, first things first, walking before one can run, have you considered looking at this against other insects?
Lisa: Not yet.
Dr. Hutchinson: So, can you bare that in mind. Have you made a note on that? Very seriously you should bare that in mind.
[After taking a photo we said our goodbyes.]
Interview with Dr. Andrew Hammond
In the course of our project, we had the great opportunity to interview Dr. Andrew Hammond, post-doctoral researcher at the Imperial College London in the field of malaria control through genetic-based technologies.
Besides giving us a quick overview of the general functionalities of gene drive as a very promising approach to contain malaria, he also gave us an understanding of his substantial publications.
“What a gene drive could do is, that it can spread [genetic modifications] in theory in the entire population, potentially cross whole sub-Saharan Africa. [...] It worked very well with Anopheles gambiae, which is the main vector of malaria in Africa. [...] Together with a couple of other closely related species [they] are responsible for about 95% of malaria transmission in the region. [...] In 2016 we showed, that we could spread this element through the population and [...] [the females] of the population got unable to reproduce. In theory, you could crash the whole population.”
We debated the difficulties, which malaria researcher are recently facing as well as prevention methods. Furthermore, we discussed different aspects of our project intensively. Dr. Hammond gave us a lot of suggestions regarding the experimental design, especially in conducting mosquito experiments and testing our odours. He also gave us input for the decision, where to place our trap in the field. We agreed, that placing it close to possible breeding sites, such as stagnant freshwater or on the outside of houses by eaves, is not only reasonable but feasible as well.
Finally, we came to the conclusion, that multiple approaches in combating the malaria-transmitting vectors are crucial to prevent Plasmodium falciparum from adapting to other vector species. This includes very focused approaches, e.g. gene drive, which targets Anopheles gambiae, the main vector in malaria, as well as broader approaches, which targets non-dominant vector species too.
“I do not like looking at gene drive as “the” solution. I see it as a chance to get rid of the major vectors in the most affected areas. [...] I think the technology you are developing would be extremely useful in that case, when used in regions were this non-dominant vector species are present. At the same time with other vector control programs, it would be effective, because you do not give malaria enough time to adapt to other vector species. So you want to target a range of all these vector species all at once with a range of different tools, because if you rely on one tool and they become become resistant, we are in big trouble.”
Dr. Hammond: Could you guys tell me something about your project first and then we get along with some question by the way?
iGEM Hamburg: As we told you, our project is mainly about developing a mosquito trap without maintenance. In this trap, there will be different types of E. coli. One type of E. coli will produce a toxin. It’s an α-toxin derived from a scorpion and it targets voltage-gated sodium channels. Another type of E. coli produce different types of odor baits, for example lactic acid, myristic acid and 3-methyl-1-butanol. We also try to inhibit the growth of our bacteria so that they could be alive for a long time. Another important component of our trap is a co-culture with cyanobacteria, which will provide nutrients such as glucose for our E. coli.
Dr. Hammond: How far is your project? Do you already have your genetically engineered bacteria?
iGEM Hamburg: We already have some constructs finished. At this moment, we are not sure, whether our growth inhibition module will work. Instead, we have finished establishing the bacteria which produce lactate. We’ll start testing our toxin as well as the odor baits with Anopheles gambiae next week.
Dr. Hammond: How do you plan to test these with the mosquitoes?
iGEM Hamburg: We will prepare cell lysates and add some sugar, with which the mosquitoes are usually fed. Then we are going to observe, how many mosquitoes will die within which time period.
Dr. Hammond: And you will feed them with your cell lysates with the toxin and a control cell lysate from bacteria, which do not produce any transgenes? Then you will compare both?
iGEM Hamburg: Yes, exactly. We will hopefully prove, that this toxin works as it is shown in the literature. It was ensured, that this toxin is only toxic to insects and does not have toxic effects on mammals. Furthermore, we built a test tube for the examination of our lure substances. If you do not have any further questions at this point, let’s continue with talking about your work. It’s very exciting, what you have published recently. Maybe we could make a little excurse about what you’ve done and then come back to our project.
Dr. Hammond: Sure.
iGEM Hamburg: In your opinion, what is the biggest problem about malaria and do you have the feeling, that research on malaria became much bigger in the last years? Could you give us a quick overview about the recent malaria research?
Dr. Hammond: I think people have studied on this and got a lot of data about how much money there is used for the research of malaria, but I wouldn’d be able to give you “the right answer”. In my personal opinion, I think, money on research on malaria has been at a pretty good level for a while. The Bill and Melinda Gates Foundation set out millenium development goals, in which malaria is one of the biggest things they wanted to tackle. They invested a lot of money in that. The biggest change we’ve seen in recent years has been a move towards novel technologies like gene drive and other genetic based technologies. There is certainly more funding, that exploded in terms of funding, not only from the Bill and Melinda Gates Foundation but others from this entrepreneurial groups. And also with local funding from [...] the american defence agency and they’re interested in investigation in these technologies which is quite cool.
iGEM Hamburg: What is the biggest problem about malaria? Could you give an overview of the effect of malaria on the society or the countries especially affected by this disease?
Dr. Hammond: Since the millenium developing goals in 2000 we’ve seen massive reductions in malaria because of a huge success in primarily bed nets and insecticides, which really works well. Unfortunately, I think last year was the first year that we have not seen a further reduction in the number of deaths, it actually gets worse for one year. This does not mean that the interactions are not working, because you expect some variations, but this is striking as the first year we did not see an increase in the benefits. This might point to somebodies fears that people are having that there is a growing resistance of mosquitoes to the interventions that we are developing, particularly in insecticide resistance. This is a massive problem which threatens all of the main interventions that we are using now. I think that the world health organisation prefers the strategy to try to eliminate malaria from the majority of sub-Saharian Africa within the next 15-20 years. This expectation was based on existing interventions plus an extra of 6 billion a year, which is an ortholog more that we are currently spending. That was assuring that the problem of resistance [becomes] the hell worse as it already is. And it may get worse. The money may not be there. So what we have to think about are other technologies as a solution, so that we can complement what we are doing. Not to replace them, but there are many possible technologies. We have to use as many as possible and try to find the best way to use them. On the one side, economically, but on the other hand we primarily want to get rid of malaria.
iGEM Hamburg: Would you like to sum up your research?
Dr. Hammond: I work on a technology called “gene drive” and it got a lot of attention, but we developed the first one that was shown to work in a very cool way in 2016. So we developed this genetic element that can spread to a population and transform it, so you can engineer modifications. Usually if you release this in a population, you won’t have a huge effect with a few mosquitoes. After a few years, you will still have only a few genetically engineered mosquitoes or less. What a gene drive could do is, that it can spread this modification in theory in the entire population, potentially cross whole sub-Saharian Africa. In 2016, we showed, that you can get the technology working. It worked very well with Anopheles gambiae, which is the main vector of malaria in Africa. Anopheles gambiae together with a couple of other closely related species which are responsible for about 95% of malaria transmission in the region. So in 2016 we showed, that we could spread this element through the population and as it spreads all the females of the population get unable to reproduce. In theory, you could crash the whole population. Unfortunately the mosquitoes adapt, and they develop mutations, that make the gene drive unable to spread. That makes sense, because the mosquitoes don’t want to be eliminated. We sort of predicted, that this would happen and we had a good idea of how it would happen. A year later we published another paper, showing how this happens and how the mutations are generated and propagated through the population. This is not good for gene drive, but it’s good to know, that we know this. Our latest publication is quite interesting too, because we found a way to overcome it, which was unexpected. There were several ways that have been proposed to overcome it. One strategy is rather than targeting the gene drive to one part of the genome you can target it to several. Resistance arises, because one part of the genome will adapt, create a mutation and make the gene drive unable to recognise it. This recognition is essential to make it work. So if you program your gene drive to target several places, than in theory you need resistance in all of these different places to the gene drive to fail. That is a cool way of doing it, but we didn’t even do this. We did something even cooler and simpler: So these mutations require a change in the genome that stops your gene drive from seeing it. Gene drive recognises a sequence of approximately 20 bases and this sequence is very specific. So, if there is a nucleotide polymorphism there, that might mean, that your gene drive can’t see and cut it. But the mosquitoes don’t care about a single base change, because it might not change the gene, which is encoded of this region. Examples for this are so-called “silent mutations” and this could happen if one base is different, but the actual protein produced remains the same. So if mosquitoes develop these mutations, they will be completely normal, but the gene drive won’t function. So we searched through the genome for regions, which for some reason have never shown any variation. This is not normal. In the mosquito genome, everyone in 2.2 bases is variable. We found a few of this regions, which show no variations in the world. One of this is a gene which is absolutely essential for female mosquitoes to become a female, which is one of the most conserved genes in the whole of life actually. It is absolutely essential in all insects. We programmed a gene drive to cut that piece of DNA with the assumption, that any mutation there is probably very bad for the mosquito. After a few generations you don’t generate any more females, because they all developed wrong. So the population goes extinct. So after releasing the gene drive with a low frequency, it spread to 100% and it generates a lots of different mutations, but because the gene drive causes a lot of broken DNA, the mosquito was not able to develop into a proper female. In the end, the population was completely crashed and died out. [...]
[There is only one rare polymorphism which is viable in nature in one or two countries in africa, which maybe stops the gene drive if it is reached.] [...]
iGEM Hamburg: That sounds very promising! Another question that we have is: This sounds like a very promising solution, maybe “the solution”. What do you think about that?
Dr. Hammond: That sounds very good. At this point, I it is quite difficult to say, that it doesn’t look very promising. But my concerns at this moment are, that there are fitness costs for the mosquitoes that is greater, what we measured. At laboratory conditions, it did spread, so they are clearly fit enough. We modeled this and even when there are 40% extra costs, it still spreads. I can imagine that potentially there are more than 50% costs, or when the temperature is very high or low, what could be a problem. We are investigating how we can improve this and try to push this to its limits. Another problem are resistances. We haven’t seen resistances yet, but that does not mean, that it is not possible. We have to test it in bigger populations. Also we try to make up as much as mutations as we could imagine to see if any of this creates a resistant gene.
iGEM Hamburg: What about the social acceptance of this method?
Dr. Hammond: So a staff scientist of mine asked for this in Africa. They said, that it has quite a big potential and is quite exciting. They support the idea of this method without definitely say “yes” or “no” at this point and see this could have a future role in malaria research. I think, this is the best possible outcome, we could have hoped for, because you don’t want people to say, whatever you make, gene drive, just use it. It is a good thing, that they say “we are not against using this technology in principle”.
iGEM Hamburg: Does your innovation make other precautions or safety measures required?
Dr. Hammond: Effectively, a gene drive could spread uncontrolled into a population. So I guess the question is “What if there are any unforeseen consequences?”. Taking back gene drive would be difficult. So you have to make sure, that there will be no unattended consequences. Therefore, we just started a very big study about the effect of anopheles on the ecosystem. A lot of people have done very small scale studies before, but the question not has been answered. People generally agree in the field, that this species is not present in Africa, but this is not enough to answer this question. So a strong study is much better. A recent review suggest, that it is not the main food source of any particular animal and in not a particularly important pollinator of plants. So it is not obviously important. So the other side is the remedy, which limits the impact of a gene drive. So we are also working on a kind of “antidose” for gene drive or how it could be reverted, or even slowed down.
iGEM Hamburg: That’s in fact very important too! Maybe we could come back to our project again. You’ve mention in the beginning, that many ways to target a disease is the best. Do you see any advantages or disadvantages of our trap to contribute to this approach?
Dr. Hammond: I don’t like looking at gene drive as “the” solution. I see it as a chance to get rid of the major vectors in the most affected areas. But then, this is not gonna be the most appropriate solution across the globe and in every region, so probably we have to use a lots of personalized ways of controlling this disease. You could for example go to small villages and towns and implements things like bed nets and insecticides but also the population controls this modified bacteria and you can put them into local breeding sites. Your approach targets not only the predominant vectors, because malaria is not only transmitted by Anopheles gambiae, but by several species. This species is not the predominant species in whole Africa, but there are also very local conditions with other strains present. There for example gene drive would not have a great effect. Your approach is a little bit broader and well-welcomed. So you don’t wanna an approach that eliminates tons of mosquitoes. You want to have a wide-spread suppression. Assuming your trap will be used, you want to use them for the most dangerous and predominant vectors and less propagating approaches to target those minor vectors. I think the technology you are developing would be extremely useful in that case, when used in regions were this non-dominant vector species are present. At the same time with other vector control program, it would be effective, because you don’t give malaria enough time to adapt to other vector species. So you want to target a range of all these vector species all at once with a range of different tools, because if rely on one tool and they become become resistant, we’re in big trouble. So I do like that.
My concerns with your strategy, are the delivery and persistence. Also dosage might me a problem. Is it feasible to get a dose that is high enough to be effective? So at what size of breeding grounds are you looking at? Are these breeding grounds permanent breeding grounds or very short term breeding grounds? Often in the rainy season, you got these very tiny puddles forming, which are formed for a very short period of time. Mosquitoes will breed in these. So is it very feasible to get your intervention into those puddles or is that not possible. And also: if you go for such sugar-based traps: Do you want to lure the mosquitoes outside people’s houses instead of bringing them into it? You’re looking for a very personal protection in addition to the bed nets and insecticides. So you’ve got the push and pull approach: Pulling them to your trap where you could kill them and pushing them away from the person sleeping beneath the bed nets. So I think in framing your intervention, you have to put your intervention into the context of other existing interventions. I like it, it’s cool.
iGEM Hamburg: Thank you very much. Do you have any further questions regarding our project concept?
Dr. Hammond: Well. I wanna have a good look at how you set up your experiments, because these things a very important to get a clear answer. So you have the two aspects: One is how does it kill the mosquitoes? And I think, about this part you are more confident about, because it has been tested a few times already. But perhaps, there is a difference between the cell lysates and the bacteria itselves. And what is the product going to be?
iGEM Hamburg: So do you have any further questions regarding our idea?
Dr. Hammond: I would have a good look on how you set up your experiments because these things are tough to make sure you get a clear answer so you should have two aspects of it. You have the one aspect which how does it kill them. This part you are more confident about because it has been tested a few times already but perhaps there is a difference between the lysates of the bacteria and the bacteria themselves. And then what is it that you imagine the product to be. Is the product you will be selling a super solution that already got your bacteria lysate in it or is it that you are going to be spreading these bacteria somehow into breeding ground. I am not sure exactly how you intend to deliver.
iGEM Hamburg: The bacteria itself is supposed to do. So this is one of our concerns. We are using bacteria as a motor of our trap because the main purpose of our trap is to be sustainable and have no need of human intervention for a long period of time. So we did not tell you this before but the trap is supported by a coculture. We have E. coli that produces our lure and our toxin in one place. But this production is actually started by another culture which produces glucose. These are cyanobacteria which are just dependent on sunlight. And I do not have a model of our trap right now but you have to imagine that there are like two chambers: One above contains all the cyano bacteria which are made to produce all this glucose.
Dr. Hammond: So you are creating a completely self-sustaining environment for these two populations that feed each other.
iGEM Hamburg: We tried to do this. This is our main goal.
Dr. Hammond: I mean that is very cool. Ambitious. Tough, I would say. One of the problems that you might experience is that the bacteria will tend to kick out what you put into them. So these toxins and the lures that will be produced by the bacteria, I would imagine after a couple of weeks they would have all lost this. So you need some sort of selection to keep that.
iGEM Hamburg: Now we have provided them in plasmids. This is because we do not have that much time for the project. We have only one year in order to work on this in course of the competition but of course one of our long-term goals would be to establish them as drains. But maybe another selection factor may be even more needed. We have not actually thought that much about it, it is very good input we actually need to consider. You are right. We needed to establish these cocultures first and of course it is a matter of the concentration of the lures whether it is going to work. We have heard the combination of lactate, myristic acid and 3-methyl-1-butanol should be one of the most promising combinations that we have. Like CO2 is also supposed to be a huge factor in the attraction in the attraction of malaria mosquitoes.
Dr. Hammond: Yes, it is.
iGEM Hamburg: But it is very difficult to integrate this part in our trap. So we thought about other approaches and we came to the conclusion that for example heat production is also a very important factor which is attracting to mosquitoes. So we modeled and established a new promotor which is induced by a cold shock and if the nights get cold the bacteria start to produce heat by uncoupling the electron transport chain from the ATP production for example. And you have mentioned that the production of all these proteins and those modifications is probably a very huge stress and affects the E. coli propagation mechanism very much which is why we controlled it by a gate meaning that as long as there is no glucose in the medium which gives them energy to reproduce and produce things in general there will be no lure or toxin production. So all these lures and toxins are only produced when glucose is available in a certain concentration for the bacteria. But of course it is still not a guarantee that it will work out in the end as well. However, this is one of the measurements we have taken so far.
You have mentioned before that there are breeding sites of mosquitoes. Do you have a few preferences? You are also testing those mosquitoes, so you are also conducting field tests and you probably know a lot about the ecological cycles of mosquitoes because you are researching on that. Do you have tips on where we could place our traps the best if we intend to use them on the field to protect a village efficiently?
Dr. Hammond: So I am actually terrible at answering that question. It is a big concern within the project. I get to hear about very clever people telling me about how you are supposed to do it but as a molecular biologist I am not the best at this but you do have these breeding sights for different types of mosquitoes which are typically this sort of stagnant pools of fresh water in the rainy season that are not large and typically straided. That is the sort of thing I like to go for. But that is going to be the larvels breeding grounds.
The adults will come together in swarms and they usually like to swarm in very specific areas so some of the best experts can tell you exactly where they will swarm but there is not much knowledge across the whole of Africa. There is knowledge about a couple of villages.
But in general for your trap I guess the best thing would be inside someone’s house. And potentially in Africa lots of the houses are built using eaves. And eaves are sort of like an opening in the roof. You have this opening where the roof and the wall meet and allows air to go in and keep the home cool. And at the same time doing that it allows CO2 and all these odors go out of the house and the mosquitoes smell that and then they come in and they fly straight through the eaves. So if you had to place your traps at theses eaves perhaps you would be catching mosquitoes as they are coming in into the house right where the odors are coming out most strongly. So you can benefit from the odors that are naturally coming out of someone’s home and then lure them with a little bit extra with your stronger lactate or CO2 whatever that is being produced and then kill them before they actually kill a person. Quite a cool idea.
iGEM Hamburg: That sounds very promising.
Dr. Hammond: And as a general piece of advice I would try to stick clear of including to many attractants and killing components. I would keep it minimum because it is much easier to keep your construct stable and ensure that your bacteria maintain the different components and it is all working. If you can test them separately and find this is the best attract component out of the five we have tested. And it might not be necessarily the same as the best that has been shown in publications because your bacteria might to be able to produce so much of each one. And at the concentration you are producing it might turn out that the one that is usually less good is better in your specific case. So I would pick one good attractant and I would pick one good killing component or perhaps two good killing components. Keep it nice and simple.
iGEM Hamburg: We have a last question. You are introducing some kind of genetic modification into another country, maybe a poorer country where people are not that educated. You have talked about it at the ESCH and I thought it is very interesting but maybe just for the interview: You are basically introducing something new into another country and need the allowance. Does the population know what you are doing? Does the population need to agree on what you are doing to “their” nature? Sorry for the provoking question.
Dr. Hammond: There are a few levels of the question. One part of it is it is not going to be “us” as our lab and our project that is actually going to run this. This is going to be in the hands of African scientists and African countries that are going to come together and really do this on themselves. [...] We are really hoping we are going to develop the technology, we are going to develop the mosquitoes, and we are going to try and show that they are safe and efficacious and provide recommendations of how to use it. But really this needs to be in the hands of the people how are suffering from this disease. So actually a lot of people on this project are African scientists. They have been on this project for a long time so they actually know very well how the technology works and very well how she will be implemented and they are actually the ones who are telling us how to implement it because they are “us”, they are part of our project. So it is not going to be one small group of scientist implementing this grand technology. It is going to be something in the hands of a lot of people over a wide region. The initial tests obviously going to be in one or two locations.
In Burkina Faso they are about to release the first ever modified animal ever to be pulled into Africa. And this is one of the strains we produced in our lab. It is not a gene drive; it is just a sterile strain. So the idea was that we are build up capacity and that we are going to take the mosquito strain they are going to rear it and going to get used to checking for integrity of the synthetic compounds, checking for whether they can track them after release whether they can rear them to the number we need to rear whether they can sex them and these such things. And then we are going to measure impact of the release; so how well do they mate with individuals in the wild things like this. So this is very important to build up a capacity. And I think it will give everyone the confidence to know, is it really possible that these technologies could be taken up by Africans in Africa and used to cure an African disease. And I think they are going to do it, these goals are fantastic.
iGEM Hamburg: We are also thinking about what to do with our stuff because of course we do not want to be the people that introduce something into another country and say: “We have a solution for a problem that you have worked on so long.” So we are also looking for maybe corporations in order to conduct all these things.
Dr. Hammond: As part of our project we have a massive communications team which is being going to Africa. Actually, most of our team is African. Like Africans going to other countries in Africa. And we are meeting with regulators; so with government regulators, with community leaders and chiefs of villages and anyone who has a big stake in what we are doing. And we are getting feedback on what their concerns are. We are spreading the technology in a way that is actually as relevant as it needs to be. So different people want to know different levels of detail. We are trying to help to provide info graphics and cartoons and anything to try to explain what we are doing at a different level of detail. So that we get it across as well as possible.
iGEM Hamburg: We should do this, too.
Dr. Hammond: I think cartoons are generally a good idea. And you can do them in a sort of very simple to more complicated. So if your audience wants to more they can go for the more complicated stuff.
iGEM Hamburg: That is a good idea. Then, I think we have no questions left. Except you have any questions.
Dr. Hammond: I think we have covered quite a lot.
iGEM Hamburg: Of course, we have covered so much. This is really good, we thank you so much for your time.
Interview and group discussion with Dr. Mirko Himmel
Projects dealing with genetically modified organisms (GMO) offer a great chance to recreate living organisms in a novel way, opening new possibilities to address problems. However, taking advantage of these new opportunities comes with responsibility for the GMOs as well as for the environment. The big keywords here are biosafety and -security. While developing the S.H.I.E.L.D as a malaria prevention method this year, we used bacteria which were modified to sustain itself for a potentially indefinite amount of time while producing a neurotoxin. Regarding these two aspects of our project, biosafety was of great concern to us. To discuss the risk factors of our project with an expert, we invited Dr. Mirko Himmel from the Carl Friedrich von Weizäcker-Centre for Science and Peace Research. He holds a degree in biochemistry, with a specialisation in biological arms control and biosecurity matters today. He gave us a detailed introduction into biosafety and security focusing on the difficulty of Dual Use Research of Concern (DURC). This informative lecture was followed by an open discussion addressing potential issues in safety and security as well as possible solutions. Lastly, Dr. Himmel raised the topic of important and sensible precautions for lab work.
The first major topic of the discussion was possible off-target organisms of the S.H.I.E.L.D. In the device we developed, the toxin produced by our bacterial culture is separated by a hydrogel from the environment. Due to this specific design, only animals that can sting this gel have access to the toxin and can suck it out. This prevents any other animals from getting in contact with the toxin while the trap is intact. Furthermore, the composition of attractants used in the S.H.I.E.L.D. are specifically designed to lure mosquitoes, reducing the chance other animals might fly into the trap.
Under normal operating conditions, the GMOs are entrapped in our device. A nanofilter with pores small enough to prevent the E. coli from exiting and other microorganisms from entering the S.H.I.E.L.D. is placed between the hydrogel the mosquitoes land on and the dextran-based one from iGEM Eindhoven 2018 which contains E.coli. Nevertheless, there is a chance of exposure, for example in the case of severe damage, and escape safety needs to be considered. The bacteria we use are almost as fit as normal bacteria and they can sustain themselves over a long period of time. However, our implemented growth inhibition module is not only controlling cell size but also suppressing cell division, making it impossible for the bacteria to proliferate and spread even under ideal circumstances. An additional suggestion was the introduction of a separate kill switch before using the S.H.I.E.L.D. in the field, such as the Amber substitution kill switch introduced by iGEM Darmstadt 2016. In this strain, a stop codon called Amber codon is introduced into a transcription factor which inhibits the expression of a lethal gene. In the S.H.I.E.L.D. the amino acid that corresponds to the Amber codon and does not naturally occur in E. coli would be provided by the cyanobacteria. In the absence of the amino acid the transcription factor would no longer be produced, causing the activation of the lethal gene.
Another important topic was the selection of the insecticide used in the S.H.I.E.L.D. The data for the toxin we originally chose were not sufficient to ensure safe usage in the lab or the trap itself. Not only could the toxin be potentially harmful to off-target organisms in case of damage to the trap, but it might pose a health risk to people working with it in the lab. Dr. Himmel stressed that we would always have to assume higher concentrations of toxins when produced in the lab than could be observed in nature. Given that information, we were not able to state with certainty that working with the toxin would be in accordance with the safety regulations of a biosafety level 1 laboratory.
As a consequence, we decided on an alternative insecticide, namely BjalT. It is a neurotoxic polypeptide derived from the Judean Black Scorpion which acts on voltage-gated sodium channels and most importantly, proven to be harmless to mammals.
We also discussed the issue of modification and misuse of the trap for possible malicious purposes. One potential misuse addressed was the decantation of toxins that diffuse through the hydrogel. However, considering the small amount of toxin produced and the specificity of the toxin, this is not a concern. There are other possibilities to collect the toxin; one could try to cultivate the bacteria to produce bigger amounts of it, but the growth inhibition module and the co-culture with the cyanobacteria make it hard to culture them to larger populations if isolated. Moreover, there is the risk of misuse of the device as a bioweapon or to kill animals besides mosquitos, for example bees, by replacing the toxin. For this to work, though, an individual would need great expertise as the multiple aspects of the trap would have to be changed. Not only would the hardware design needed to be altered, but one would have to exchange the toxin and eliminate the growth inhibition.
To further increase the effort needed to misuse the trap we decided to post sensible information about the method of toxin production only on the iGEM website, rather than spread it on social media.
We discussed testing our odour baits and toxin on Anopheles gambiae, the main vector of plasmodium falciparum. We worked with mosquitoes that were not infected and thus harmless to humans. All the experiments involving mosquitoes took place in the Bernhard Nocht Institute for Tropical Medicine. Dr. Thomas Jacobs, who supervised our work, was also able to answer questions that remained unanswered during our discussion with Dr. Himmel. Namely, whether or not one could expect the occurrence of a resistance to our toxin and the possibility of pathogens growing on the hydrogel.
As we would not want the S.H.I.E.L.D. to depend on antibiotics, we discussed the necessity to introduce the DNA stably into the bacterial genome rather than working with plasmids as we currently do.
At a later point in our project we visited Dr. Himmel again, updating him on our progress and improvements we made after our group talk.
Interview with Dr. Thomas Jacobs
Towards the end of our project we had the chance to work in the laboratories of the Bernhard Nocht Institute for Tropical Medicine (BNI) where we conducted experiments on mosquitoes to test our hydrogel as well as the bait and toxin. Before we started working in the lab we talked to Dr. Thomas Jacobs of the BNI to gain knowledge about the malaria-transmitting vectors and to discuss some safety concerns raised during discussion with Dr. Mirko Himmel.
He gave us more detailed information on the seasonality of the mosquitoes and talked about successes and difficulties of vector control both in Africa and Germany.
He was able to diffuse our concerns that different pathogens might grow in our trap and could thereby be distributed by mosquitoes.
“No, I think this is for me very unlikely […] I would not expect that you have living pathogens on the trap’s surfaces for a very long time.”
Another major concern of ours was the occurrence of resistances to the insecticide we are using.
“Well, I think the toxin should be effective. I would not expect any development of resistance because normally they should not see this kind of toxin.”
He stressed the importance of a dose high enough to swiftly kill the mosquitoes so there would be no sufficient time for them develop and pass on a resistance.
iGEM Hamburg: Thank you very much, for taking the time to talk to us. Could you briefly introduce yourself and tell us what you do here at the BNI (Bernhard Nocht Institute for Tropical Medicine)
Dr. Jacobs: My name is Thomas Jacobs. I am a group leader here at the BNI. We are working in the field of immunology. I am working on how the immune system is regulated, for example how it reacts to malaria. [...] Our major research quest is to find out why children on the one hand can suffer from severe malaria and die and [...][on the other hand] somehow develop a kind of clinical immunity. Over time the situation or the disease is attenuated and eventually they are protected.
iGEM Hamburg: Can you tell us why the science of malaria research has gained importance in the last years?
Dr. Jacobs: I think it was actually important all the time. It is a major bottleneck for the development in [...] Sub-Saharan Africa because of the very high disease spread. The problem is, that over time when you develop new medications you develop resistances. This is increasing over time, so there is a lot of pressure to get hands on new measures to [...] stop the disease or stop the transmission of the disease. That is the problem we are facing now and I think therefore there are major efforts to design new vaccines strategies. We know that normal vaccines strategies, like done in the past for virus diseases are not working in malaria. In my opinion that is why there is so much new science in malaria research.
iGEM Hamburg: Is malaria linked to climate change? Do you think it is possible for malaria infected mosquitoes to come to countries where they were not before?
Dr. Jacobs: No, I actually think this is more for virus diseases, for example West-Nil-virus and dengue fever. There are certain mosquitoes which can come to Germany and I think their introduction will be faster if we have higher temperatures. But with malaria, we must keep in mind that we had malaria in northern Germany for quite a long time. The major question is how to control the vectors. Each country in Africa that has an economical situation of growth made major steps forward. Malaria can be controlled to a big extend if they have vector control programs, screening programs and the people have access to medication. I think [...] [Malaria is] a poverty related disease and not so much related to climate change.
iGEM Hamburg: Alright. Do you think that it is possible that in the future we see the Anopheles mosquitoes here in Europe?
Dr. Jacobs: I think that could be possible. But again, we have to keep in mind we have mosquitoes in Germany that are able to transmit malaria. So, we have had a certain case of airport malaria for example in very hot summers where infected people got bitten by a mosquito and then on a very small scale we can even have a small epidemic of malaria transmitted by German mosquitoes.
iGEM Hamburg: We have heard about gen-drive. Will this approach be pursued and why is it not used yet?
Dr. Jacobs: Well I think this is a very interesting technology and I think many labs are interested in this technology. There are even small-scale applications of the gene drive technology. But we have to keep in mind that we render mosquitoes, or we have genetically modified mosquitoes. I think there are major concerns about this technology and I think we should invest more into science and study this in depth before we actually start using this technology. We already have certain measures to control the vectors. For example, in the Region of the Rhein we tried and were able to control vectors to a very high extend. Without it we would have a lot more mosquitoes there. So I think we do not need the gene-drive technology, at least not at this stage.
iGEM Hamburg: So, you said that you want to make further investigation, more experiments with gene-drive. How would these experiments look like?
Dr. Jacobs: Well, to be honest I am not an expert in gene-drive technology and I would say, that we have to really proof that this technology is safe. I think this is what we should investigate first and then we can go one step ahead. But I think when we step one step back to the classical technology like vector control and bed nets we have a good opportunity to control the mosquitoes, even in Africa. We have to invest a lot of money to set up this basic technology. This should not only be in one area this should be applied in the whole region. This is low-tech, but it is proven very often, that this low-tech is working.
iGEM Hamburg: Can you tell us somethings about the seasonality of the mosquitoes?
Dr. Jacobs: I think it depends really on the region where you are. But normally you can see the increase of the transmission [of Malaria] during and after the rain season. For example in Ghana we have major transmission in March, April and May and then again in September, October and November.
iGEM Hamburg: Which of the ways to fight malaria is the most promising one today?
Dr. Jacobs: To fight malaria or to control the vector?
iGEM Hamburg: Could you answer both questions?
Dr. Jacobs: I think there are normal control measures, for example getting rid of wet areas. For example it is forbidden in Hong Kong to get water trapped in a bottle, so mosquitoes cannot breed. But I think that in Germany for example the BT-toxin application works quite well in the Rhein valley. We have also made studies here at the BNI about the use of bed nets. Bed nets for examples are really working quite well and have a major impact on transmission. Secondly, I think it is important to treat the people with allow infection with the malaria parasite. They will not get sick but can still be the host for the parasite and mosquitoes can be infected when they are feeding on their blood. So actually we need screening and treatment of all the infected people, even those with a low level of infection so that we can stop the transmission of the parasite to the mosquito. I think this is a very important thing to do these days.
So normally I think to control 90 % of the disease is very easy, because you can make mass drug administrations. So in endemic regions where most of the people are infected you will provide the drug and the [prevalence] will go down and you will see a major benefit. But once you stop the treatment infection numbers will again increase because you have all these low-level infections and mosquitoes can be infected on their blood. This causes a major rebound. We have seen this in regions where they made major efforts to control malaria and
malaria was nearly extinct. Once they stopped the measures they had a worse situation than in the beginning. So once you start to control malaria you must not stop it. I think this is important.
iGEM Hamburg: Are there traps, which are designed to heal the mosquito from the Plasmodium instead of killing the mosquito?
Dr. Jacobs: I am not aware of any traps, which can do this. Manly traps are used to kill mosquitoes. But there is one example which might be similar. There is a vaccination of humans against a protein from malaria, which is only expressed in mosquitoes. When the mosquitoes suck the blood they will also ingest these antibodies [formed in the human] and the Plasmodium will die within the mosquitoes. So this vaccination is not beneficial for the human or at least not for the patient directly. It actually will kill the parasite in the mosquito. So somehow you get a “vaccination of the mosquitoes”. – So to say. There are some ethical problems, because you have to vaccinate the people and they will not directly benefit from the vaccinations. But the vaccination can have side effects and so on and so forth. However this might be very interesting, because there are not many polymorphic molecules in the mosquito, which will change over time since in the mosquito there is not a big immune system and there are no antibodies in the mosquitoes. Once the parasite needs this protein the antibody will be there and will prevent the function of the protein. I would not expect any resistance at this stage. So this is actually similar to what you asked.
iGEM Hamburg: How about the following generation of mosquitoes?
Dr. Jacobs: The Plasmodia will be killed within the gut of the mosquito. So the mosquito will be healed as you suggested and will developed normally over time. But over time this human antibodies in the mosquito will be degraded. There are also proteases in the mosquito for example. So the antibody will be vanished. It will not be a long lasting action, but with the next blood meal they will take up the antibodies and again they will be protected.
iGEM Hamburg: What do you think about our approach for a self-sustaining mosquito trap?
Dr. Jacobs: I think it is really interesting and I think this technology is amazing. I am not sure if the prize will actually meet the criteria which we will need for Africa. I do not know, I just do not know. I think for German situation it will be wonderful, because we are used to spend a lot of money for such devices. But for example, in Africa where we even have discussions if we should spend 3 € for a new vaccine per dose. So, I do not know if you can actually build this trap for Africa. I do not know maybe you have to find a sponsor, like Bill Gates for example who would like to invest a lot of money in these traps. But I think apart from this, it is an interesting technology
iGEM Hamburg: Let’s imagine we get founded and we can invest enough money to develop the trap. Do you see problem within the trap? Problem with the concept or things that might not work?
Dr. Jacobs: Well I think the toxin should be effective. I would not expect any development of resistance because normally the mosquitoes should not come into contact with this kind of toxin. From this angle I would not see any problems. No, not yet.
iGEM Hamburg: Do you think, that there could be a resistance development against the toxin?
Dr. Jacobs: No normally not. I would assume, if the dose is high enough and the mosquitoes will be dead afterwards there will be no transmission of resistance. We made this experience in Germany where we used this BT-toxin over a very long time. I do not think there are any issues with that.
iGEM Hamburg: Do you think there are pathogens that can grow on our trap which can be transmitted by a mosquito? And therefore, our trap could help to spread it.
Dr. Jacobs: No, I think this is very unlikely. Normally the transmission of pathogens by mosquitoes is really relying on sucking blood. I would not expect that you have living pathogens on the trap surfaces for a very long time. Even should there be microorganisms on the trap, they would not easily transmitted by mosquitoes. The proboscis is antimicrobial and we do not observe microorganisms from any surfaces to be distributed by mosquitoes. If that were the case we would have a whole lot of different problems. We have a lab where we try to experimentally infect mosquitoes and even in the lab it is complicated to infect mosquitoes. So, I think this will not happened by chance.