Discovery

Dengue fever is carried in the tropics all around the world by the mosquito Aedis aegypti. The disease passes from person to person via these mosquitoes. Dengue doesn’t exist in forests and fields, only where people live, so it’s particularly prevalent in towns.

Dengue is endemic in Brazil. The only weapon against it is chemical spray. But it’s hard to catch the mozzies as they lurk in the tiniest pool of water. Also, once you get infected with Dengue (symptoms ranging from mild-flu-like to bedridden ‘breakbone fever’) all subsequent infections just get worse. It’s why the Brazilians are desperate to find a new way of stopping Dengue – for which there is no vaccine.

That’s the reason Brazil is the first country in the world to run a GM mosquito public health programme. They already have facilities for producing vast numbers of sterile mosquitoes – though they produce them via irradiation. Last summer we reported on caged outdoor trials in Mexico of mosquitoes genetically modified to fight Dengue.

In Brazil in February this year, UK company Oxitec, in collaboration with the University of Sao Paolo and a company called Moscamed in Brazil, started doing test releases in the city of Juazeiro, in Bahia province of N E Brazil. (Juazeiro is close to Brazil’s major tropical fruit exporting city of Petrolina). The test was to see whether the GM mozzies would survive and do their job in the wild, which they seemed to.

Should we deliberately make a living organism extinct? Some argue that we should, where that organism is a deadly virus that killed around 300 million people during the 20th Century, leaving many more scarred for life. The organism in question is the smallpox virus.

Smallpox is one of the few complete medical success stories, the only disease to have been totally eradicated in Nature. The last natural case occurred in 1977 in Somalia, after a long and intensive vaccination campaign that used 2.4 billion doses of vaccine.

But there was one more smallpox death in 1978, when a laboratory worker in Birmingham, England was accidently infected with virus stored there. Those stocks were destroyed, leaving only two secure reserves; one in Atlanta in the USA and one now in Siberia. But should these too now be destroyed?

Jon Stewart looks at the history of smallpox and discusses its possible future with Edward Hammond, consultant to The Third World Network NGO, who believes the virus should be destroyed; and Raymond Weinstein of Georgetown University School of Medicine who makes the case for preserving it in secure facilities for possible research to combat disease or bioterrorism.

Physicist and science writer Brian Clegg guides Jon Stewart on a journey though the science of aeroplane flight. The whole experience of flying is filled with scientific discoveries – starting with how huge, heavy jumbo jets manage to get off the ground, how they navigate and why, unlike in Hollywood movies, it’s practically impossible to open the door mid flight?

Plans are advancing for the biggest radio on Earth, an array of up to 3000 radio telescopes across a continent. The Square Kilometre Array (SKA) will have its central core in either South Africa or Western Australia, but its spiral arms of outlying giant dishes will reach out 3000 km in every direction. Astronomer Dr Lucie Green hears how it could search for habitable planets, intelligent life and new-born galaxies.

The ambitious €1.5 billion plan is a partnership between 70 institutions in 20 countries, with its headquarters at Jodrell Bank near Manchester. But wide-open spaces with sparse population and few mobile phone masts are needed to build it. So there is fierce competition between the two remaining short-listed host countries as the time to decide between them approaches. For one proposal, the array would be centred in the ancient desert of Western Australia, with outlying dishes as far away as New Zealand. The other comes to a focus in South Africa’s Northern Cape and reaches out to Ghana, Kenya and Mauritius.

The rewards could, quite literally, be astronomical, with 50 times the sensitivity of anything before and the ability to detect alien broadcasts from distant solar systems and even to image the gaps in dusty discs where planets may be forming. But the astronomers also have to justify the cost at times of financial restraint and given that the array will not be complete until 2024. And engineers have to prove that it will be possible – something they’ve already begun to do by linking together 7 existing radio telescopes in the UK with a new high-speed fibre optic network.

Producer: Martin Redfern

Can surgery be submitted to the same rigorous clinical trials as drugs to ensure the right surgical procedures are being carried out? Or does the very nature of the craft make this impossible? Every operation is unique to each patient and the surgeon who carries it out. No two surgeons will ever carry out the exact same operation. How do we know therefore, which procedure is best?

The answer is not straightforward. What if a surgeon decides to alter regular surgery in some way. How does he or she evaluate whether the new alteration is better than the old? If the same were to happen with a drug, it would take six or seven years to make one ingredient change, carry out randomised clinical trials to test the safety and efficacy of the alteration before coming into use. Not so with surgery.

By its very nature, surgery, a craft, is dependent on the surgeon carrying out the operation, on the patient before him and on the manifestation of the disease he is dealing with in that patient. No two patients are the same, and thus no two operations will be the same.

Although 30% of hospital admissions require surgery, only 2% of medical research funding goes into testing whether surgical procedures have a scientific grounding. Surgeons are now trying to alter that figure and see how this problem can be addressed.

In this programme Geoff Watts looks at the problems faced by surgeons and how they may be overcome.