E-interviews are a new section on MalariaWorld, where we interview members about their work and role in the field of malaria. This is our first e-interview, with Mr. Fredros Okumu, working at the Ifakara Health Institute in Tanzania and PhD student at the London School of Hygiene and Tropical Medicine.
A: I’m presently involved primarily with two malaria research topics. Firstly, we are trying to figure out if there is any added advantage of using insecticide treated bednets in houses that are also sprayed with residual insecticides; in other words investigating potential benefits of combining Insecticide Treated Nets (ITNs) with Indoor Residual Spraying (IRS). Though these are the most common malaria vector control methods, and though they are in many instances used together in the same households, there is no evidence that combining them would have greater impacts on vector populations and or malaria transmission than using either method alone. We are conducting experimental hut studies to determine if there would be any synergisms or redundancies with such combinations, but also to determine which insecticides are most appropriate whenever the two strategies are combined.
Q: What made you decide to move into medical entomology and work on attractants for malaria mosquitoes? Tell us about your career path.
A: When I started working on Medical Entomology, I was an 18 year old fresh high school graduate, and to a great extent I was driven by an inner spirit of adventure. My long term friend, Dr. Wolfgang Richard Mukabana, had recruited me as a volunteer in his PhD experiments, essentially to sleep inside closed tents as a ‘mosquito bait’ during experiments in which he wanted to characterize people who are most attractive to malaria mosquitoes versus people who are least attractive. It was 2-4 months later that I realized I could possibly exploit my teenage interests to help find a solution to one of mankind’s greatest problems, malaria. The greatest motivation at the time was provided by a group of scientists with whom we worked western Kenya, notably Dr. Ulrike Fillinger, presently at London School of Hygiene and Tropical medicine, Dr. Gerry Killeen whom I later joined at Ifakara Health Institute, Dr. Bart Knols (MalariaWorld), and perhaps most importantly Dr. Mukabana, now at the University of Nairobi.
Q: You recently developed a blend that is 3-5 times as attractive as a human being. That sounds unbelievable. Tell us how you did come up with this.
A: Perhaps I should start by saying that it should not be unbelievable that we have a synthetic mosquito lure that attracts more mosquitoes than humans. I believe that even more attractive blends can be developed, based on methodologies similar to the ones we used. Secondly, the scientific community has worked on this subject for more than two decades, mainly identifying, isolating and characterizing individual compounds found in human sweat, body odor or breath, which can attract or repel mosquitoes. In the beginning we hypothesized that because mosquitoes can choose more attractive people over less attractive ones and because different people produce different amounts of known natural attractants, that it might be possible to make something that consists of several of these individual attractants, and therefore create a synthetic mixture which smells like real humans, and which would potentially have several applications in mosquito control. What we have done since 2 years ago was to put together some of these candidate attractants (that had been pre-identified by previous researchers including members of our research consortium at the time). But there were two very important things that we did differently and which we believe led to the success. One, we started by determining the optimal doses at which each of these individual attractants should be added so as to obtain a maximally attractive lure, and two, while previous researchers have worked mainly inside laboratories and small wind tunnels, we opted to optimize our synthetic lure in a very large (200m2) screened cage and then tested it in a rural village using experimental huts. This way we demonstrated that if put a distant apart (in different huts) our synthetic odor blend consistently attracts 3-5 times more mosquitoes than humans, which was far beyond our expectations at the time. But we also observed that if humans are inside the same huts as the lure, then the lure is inferior, meaning the lure is best for long range use. This is why we believe also that there might be some synthetic lures previously developed by other researchers that may show the same or perhaps greater efficacy than our lure, but which unfortunately have not been tested in a real life or long-range scenario the way we did.
Q: You received an exploration grant from the Gates Foundation, what are you doing with it?
A: Thanks to the Global Health Discovery program of the Bill and Melinda Gates Foundation, the Grand Challenges Explorations grant was awarded to us in May 2009. These grants are awarded generally to explore innovations for future application in public health. The purpose of our grant was to test the concept of using optimally located outdoor interventions to complement insecticide based intra-domiciliary vector control methods like ITNs and IRS. Specifically we are fabricating decoy mosquito resource points to lure mosquitoes that are seeking blood, egg laying grounds or resting grounds. Some of these decoy sites are embedded with mosquito killing agents such as pathogenic fungi. Using computer based Geographical Information Systems but also participatory community mapping, we are also developing location models with which we can identify the best places to locate these devices so as to achieve maximum health benefits. By consistently integrating these new technologies with existing methods, primarily ITNs and IRS, we envisage that even in areas of intense malaria transmission, dynamics of control can be shifted so as to achieve local elimination more readily and cost effectively.
Q: You were recently awarded the Scientist of the Year (2009) award at your institute. What does that do to you, and lastly, where do you see yourself ten years from now? What would you like to be doing then?
A: 2009 was a particularly beautiful year for me and for our research group, even though there might have been a few difficulties at the beginning. To be named Scientist of the Year in an institution with such a magnificent international reputation as Ifakara Health Institute is indeed a great achievement for me at personal level. It has indeed provided an immense motivational boost at this stage of my science career. In the same year, I also won the American Society of Tropical Medicine and Hygiene Young Investigator Award (2009). But, I genuinely consider the ‘IHI Scientist of the Year Award’ as the most significant ever in my career. And like any other scientist would be, I am very very happy about this award. At the institutional level, I imagine that this recognition may also motivate other investigators, especially young scientists who may wish to do even greater things and achieve greater goals in their careers. On the other hand, I take this as a worthy challenge to continue to pursue answers to key research questions in public health.
It is difficult to say where I will be in 10 years or what I will be doing. But in summary, I wish to actively participate in public health research and related campaigns towards elimination and possibly eradication mosquito-borne diseases notably malaria. God willing, this happens in my lifetime. And similar to the beautiful mentorship that I received from my long term friends, colleagues and teachers, I hope also that I can provide the same or even better academic and scientific support to students and future scientists that come after us.
Q: What book had a major impact on you?
A: I will name three books in this case because these have nearly equally affected my perception of life and in many ways my view of human survival versus the environment in which we live:
1): Malaria Capers: Tales of Parasites and People by Robert Desowitz.
2): Guns, germs and steel: a short history of everybody for the last 13000 years by Jared Diamond:
3): The Commonwealth of Thieves: The Sydney Experiment by Tom Keneally
Thank you very much for this interview.
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