£2.5million Wellcome Award for Keele researcher

Share |
Posted on 02 February 2011

The Wellcome Trust has awarded Dr Gordon Hamilton in the Centre for Applied Entomology and Parasitology, Institute for Science and Technology in Medicine, and co-applicant Dr Orin Courtenay, Warwick University, £2,562,995 for a Strategic Translation Award, “Field trials of synthetic sex pheromone to reduce visceral leishmaniasis (VL) transmission by Lutzomyia longipalpis in Brazil”.

The 40 month project follows on from a successful University Translation Award awarded to Dr. Hamilton in 2007, which demonstrated the feasibility of using sex pheromone as part of a “lure-and-kill” approach for controlling the sand fly L. longipalpis in the field.

Among parasites transmitted by insects, single-celled parasites of the genus Leishmania are second only to malaria parasites (transmitted by mosquitoes) in terms of their impact on health. Leishmania parasites cause the potentially fatal disease, visceral leishmaniasis (VL), which affects some half a million people worldwide each year.

Currently the disease is controlled by the use of therapeutic drugs. These can have unpleasant side effects for the patient because they are toxic, they are expensive which limits their availability and may be difficult to administer because of poor health care infrastructure. There is also evidence of the parasite becoming resistant to drug treatments. Vaccines may be developed in the future but none are available yet. Historically controlling the insects that transmit disease (vector control) has led to disease control and mosquito control to reduce malaria transmission is a good example. This is however an expensive and environmentally damaging option and according to the World Health Organisation new methods for disease control are urgently sought.

In South America, the parasite that causes VL is transmitted by female L. longipalpis sand flies between infected and uninfected dogs (the mammalian reservoir of the infection) and to humans. If sand fly feeding on dogs and humans could be better controlled, or even prevented, transmission would be less likely to occur, and consequently the number of dog and therefore human cases may be reduced.

The strategy adopted by Dr Hamilton and his team has been to achieve vector control through an innovative 'lure-and-kill' approach which targets the female sand flies. This approach exploits the natural communication system that controls sand fly reproductive behaviour. At dusk, male sand flies aggregate on and around host animals, releasing chemicals (sex pheromones) that attract the females to mate. Dr Hamilton and his colleagues in Keele and Brazil; Dr Krishnakumari Bandi, Dr. Dan Bray and Dr Reginaldo Brazil have demonstrated that the male pheromone can be synthesized in bulk from an inexpensive and easily obtained plant derived intermediate and shown that it can be used to attract female (and male) sand flies to insecticide treated targets in the field.

The Strategic Translation Award will allow Dr Hamilton and his colleagues in Keele and Warwick, in collaboration with colleagues and agencies in Brazil, to determine if wide scale deployment of synthetic sex pheromone, with an appropriate insecticide treatment, will reduce the population of L. longipalpis and therefore VL incidence and infectiousness. The project will therefore devise new ways to synthesise, formulate and present the sex pheromone and then measure the effects of a wide-scale intervention on sand fly abundance and disease incidence in a 3-arm cluster randomised trial. A significant additional commercial objective of the award is to development the innovation to the point where it can be commercially exploited as a healthcare product.