Professor Chris Curtis
Chris Curtis was one of the world's leading medical entomologists, and most of his professional life was devoted to the development of low-technology methods for mosquito control. In the field of malaria control, his work helped to establish insecticide-treated mosquito nets as the dominant technology for prevention and the control transmission.
His influence as a teacher has been even greater: he gave lasting inspiration to countless students, and there is still a worldwide community of students and colleagues (including the writer) who are linked by what Chris taught them about how to do science, how to value it and how to enjoy it.
Chris was completely dedicated to the cause of useful science in the service of practical public health. Even during his PhD, a study of basic genetic mechanisms in fungi, he was looking for useful applications of this work, and came up with the idea of using chromosomal translocations as a method of genetic control. He went on to develop translocations in tsetse flies, which are especially vulnerable to this form of control because of their low fertility, and then to work on the genetic control of mosquitoes in a World Health Organisation research unit in Delhi, India. When false rumours about biological weapons and the CIA caused the Delhi unit to close, Chris joined the London School of Hygiene & Tropical Medicine in 1976. In London, he started to work on various forms of ‘appropriate technology for mosquito control’, which would remain the focus of his research for the rest of his life.
One these technologies was a simple idea for control of Culex mosquitoes, which carry the disfiguring disease filariasis and breed in places such as pit latrines, soakage pits and flooded
basements. The idea was to use loose beads of expanded polystyrene (the white plastic spongey packing material) to form a self-sealing layer on the water surface and suffocate the larvae. The first field trials of this method, designed by Chris and carried out by colleagues in Zanzibar and Dar es Salaam, produced several world records: more than 20,000 adult female Culex mosquitoes emerging from a single pit in a single night; breeding in a pit latrine prevented for more than seven years by a single polystyrene-bead treatment; better than 98% reduction in adult mosquitoes from community-wide application to all the breedingsites in a village. They also produced a typical Curtis-style joke. One day the team was inspecting a large flooded soakage pit, when the concrete cover began to give way, and Chris fell in. From then on, he took every opportunity to observe that when immersed in the soup, he was "not so much swimming as going through the motions".
Since the 1980s, Chris's main research focus has been on practical methods for controlling malaria vector Anopheles mosquitoes, especially the use of insecticide treated nets (ITNs). He led some of the very first work using experimental huts to study the entomological effects of ITNs and how they work to control malaria transmission. From then on, until the present, Chris's work has continued to promote and inform the development of this technology, as it gradually moved to centre-stage as a means of practical malaria control. Much of this was concerned with the ‘mass effect’ of ITNs. When ITNs are used by most people in a village, there can sometimes be a ‘mass effect’ on the local mosquito population, reducing its ability to transmit malaria and giving extra protection to everyone in the area, including those without nets. This has implications for the way that ITNs should be distributed. Chris's team originally predicted this effect, and were the first to demonstrate it in the field and to confirm the mechanism that mediates it. Chris himself developed this concept into a political argument in favour of ‘free nets’ - the principle that donor funds should be used to give ITNs free of charge to everyone in the target population. Chris became a tireless and highly influential campaigner for this cause, and against the notion that nets should be sold, or should be targeted only at the sub-groups more vulnerable to malaria (especially small children). In doing so, he contributed (with many others) to a significant strengthening of political will in developed countries, and thus to a truly vast increase in donor-funding for malaria control. Now, about 50 million treated nets have been given away for free in the way that Chris promoted, preventing tens of thousands of deaths due to malaria among African children.
In the process of this research, Chris was also responsible for introducing numerous techniques - mostly methods of evaluating interventions - that are now considered standard. He was also a rigorous and highly regarded theoretical scientist, and produced simple models of genetic control in insects, and the evolution of resistance to insecticides. These were back-of-an-envelope style models, but they have proved to be remarkably durable in their influence because of the way they identified and explored the 0practical weaknesses as well the theoretical strengths of bright new ideas.
No account of Chris's research would be complete without some mention of the way he went about his work, which is one of the reasons why he has been so influential. First he was invariably straightforward, never over-elaborate. Second, he was always the sceptical scientist, rigourous and careful. He had a luminous integrity that sometimes bordered on the naive: you could never suspect Chris of falseness or pretension of any kind. He was modest: although he worked productively and effectively with colleagues from many disciplines all over the world, he never assembled a big research team, and was invariably careful to give the primary credit to his collaborators, assistants and field teams.
This selflessness and generosity was extended to Chris's students. All over the world there are ex-students who are still inspired by the way that Chris showed them how to work. The number of messages sent since he fell ill, and the strength of feeling that they express, show that Chris made a strong and lasting impression on a very large number of people, of all kinds and in all walks of life.In fact, his influence as a figure of inspiration may in the end to prove to be even more important than his contributions to science. Many of these messages mention Chris's wife Jill, to whom he was devoted, weekend trips to their cottage in Somerset, and field trips to look at mosquitoes in Epping Forest and the Kent marshes. They mention Chris's prodigious intellect and moral sense, his compassion, dedication, and kindness - as well as his famous antidote to writer's block: "don't get it right, get it written!".
Although he retired five years ago, Chris continued his usual classroom teaching until very recently. Indeed, he was in the middle of his own 5-week course on vector control when he first
fell ill. His collapse at home, in mid May, came as a complete surprise and shock. Chris was ill and awake for only a mercifully short period. In due course, his wife Jill and his colleagues will organise a thanksgiving get-together to celebrate Chris's life and work.
Dr Jo Lines