Malaria, Mosquitoes and Man - Breaking a Deadly Cycle

Malaria kills one child every thirty seconds in Sub-Saharan Africa, according to recent estimates. It is a huge problem threatening over 40 per cent of the world's population and is still on the increase. The infection causes more than 300 million acute illnesses and at least a million deaths annually and is recognised as a major factor impeding the development of some of the poorest nations.

It is a major health challenge worldwide, yet the resources devoted to tackling malaria are woefully inadequate and it is often argued that if it had the same impact in Europe or the USA, it would be receiving far greater attention. Yet with accelerating climate change, the fact that it could spread further is no longer beyond the bounds of possibility.

Past strategies to kill off mosquitoes with insecticides failed as they developed resistance, just as malaria itself has developed resistance to some of the drugs used to control the disease.

Researchers in the Centre for Applied Entomology and Parasitology, part of the Institute for Science and Technology in Medicine at Keele University in the West Midlands region of the UK, are focusing their efforts on trying to break the transmission cycle through which the disease is passed on, by studying the complex relationship between the parasite and the mosquito itself.

By studying the biology of the interaction between host and parasite, they are looking at ways that it could be altered, biologically and genetically, to prevent the parasite being passed on by the mosquito.

Discoveries of particular interest are that the mosquito kills off many of the parasites in its gut in the first 24 hours, posing the question as to whether this action could be enhanced? Additionally, the egg production of an infected mosquito falls, possibly to preserve resources and stay alive, while the malaria parasite develops to an infective stage, leading researchers to question whether this could be altered so that the mosquito dies before the parasite is ready.

They are also working on a novel approach to genetically engineering mosquitoes by creating a “docking site” on a mosquito chromosome, which could provide a stable and reliable way of introducing a gene to a mosquito, for example to combat malaria.

The ultimate aim would be to replace natural populations of mosquitoes in disease endemic areas, with a “genetically modified mosquito” incapable of carrying the malaria parasite.

Footage:
- Mosquito insectary
- Mosquito cages
- Mosquito feeding on arm
- Mosquito embryos injected with DNA
- Genetically modified mosquito images under UV

Interviewees:
- Professor Hilary Hurd, Professor of Parasitology, Keele University
- Professor Paul Eggleston, Professor of Molecular Entomology, Keele University