Gold is an indispensable component in a range of diagnostic medical technologies. But from extraction to manufacture, there are challenges at every step of the way. Photograph: John W Banagan/Getty Images
Does gold save lives? When it comes to malaria, the answer is yes.
Malaria is one of the most significant health issues in the world today, putting high economic and social burdens on those countries most affected. According to the World Health Organisation (WHO), there were about 219m cases of malaria in 2010, leading to an estimated 660,000 deaths, concentrated in the poorest countries in the world.
However, malaria is both preventable and treatable, and incidences of malaria are decreasing thanks to improved prevention and control measures. This is partly due to early diagnosis, often carried out through rapid diagnostic tests (RDTs) – and this is where the gold comes in.
Trevor Keel, head of technology at the World Gold Council, explains: "Each RDT contains a tiny quantity of gold. It is the enabling material that allows you to detect malaria accurately. It is reliable and useful in hot countries, where you need a material that is stable, so gold is perfect for that."
The gold used in RDTs comes in particles tens of thousands of times smaller than the width of a human hair. "RDTs contain hundreds of nanoparticles invisible to the naked eye. The particles are so small, you can't even really see them with a normal microscope," says Keel.
Malaria RDTs detect specific antigens (or proteins) produced by malaria parasites that are present in the blood of infected individuals. The gold particles help to produce a simple colour change – a bright red line – that indicates the presence of malaria in the patient's blood sample. The results can be available in just 15 minutes.
But there are challenges in taking the gold from mine to strip. "Turning gold into a useful material for diagnostics is quite a challenging procedure," Keel stresses. "Each kit needs to work – these are life-threatening conditions – and every test has to be uniform and reliable."
RDTs have been available for some 25 years, but their initial uptake was slow. But it was only in the late 1990s – and then increasingly after the Abuja Declaration (when African governments agreed to increase their spending on health) and the introduction of the UN's Millennium Development Goals – that the use of RDTs gained momentum.
According to the WHO, the number of RDTs available in the public sector has gone up from fewer than 200,000 in 2005 to more than 74m in 2011. About 155m malaria RDTs were sold worldwide in 2011 – and this figure is set to rise still further.
"The total world market for malaria RDTs is growing by some 30% annually," says Russell Glanz from ICT diagnostics, pioneers of the rapid diagnostic industry in southern Africa. The Cape Town-based company produces a substantial number of these tests – some 15m last year.
"In the past, people suspecting they had malaria infections were not properly diagnosed, and were just given medication like sweets," says Glanz.
About half the world is at risk of malaria, particularly young children and pregnant women in areas where malaria is endemic. It is transmitted through the bite of an anopheles mosquito, and is an acute febrile illness, with symptoms including headache, chills and vomiting.
Treating malaria appropriately is important to cutting down this risk, but first it is essential to find out whether a patient actually has malaria. The disease used to only be tested for in laboratories, so people had to travel to be seen, making widespread screening impractical.
But this situation is much improved, says Elizabeth Streat, senior public health specialist with a focus on diagnostics, for the Malaria Consortium. "RDTs have enabled testing of malaria outside of clinics. Increasingly there has been a use of them at community level by community health workers," she says. "There is a push to scale up and increase access to RDTs by training people without high-level technical qualifications to use them."
Accurate diagnosis has also previously been a problem. Not all fevers are malarial, even though people with fever often assume they are, and malaria has in the past been treated pre-emptively. Now, the WHO recommends that all cases of suspected malaria be confirmed using parasite-based diagnostic testing, such as RDTs, before treatment is given.
Streat says diagnosis stops antimalarial therapies being overused and, in turn, the potential for drug resistance to develop. "We don't want to waste antimalarials," she adds.
Given that [antimalarial] artemisinin combination therapies (ACT) are among the few drugs that still treat malaria effectively, it is vital that they is used properly. And this means demand for RDTs is on the increase. "Malaria RDTs and the use of gold particles to visualise the result is of great importance to the Roll Back Malaria programme around the world," says Glanz.
Streat sees another possible avenue for the use of RDTs: "In some countries, over 50% [of people with suspected malaria] go first to pharmacies or drug shops. There are now a dozen or so pilots testing out the use of RDTs there. If we don't use them, we are missing out on half the people we could help."
This content is brought to you by Guardian Sustainable Business in association with the World Gold Council. Produced by Guardian Professional to a brief agreed and paid for by the World Gold Council. All editorial controlled and overseen by the Guardian.
After service in the British SAS Regiment the author became a physician and then an orthopaedic surgeon.
He has held professorial positions in Canada, Vietnam and the United States, practiced and taught orthopaedic surgery in three continents and in several wars.
He has extensive experience as an expert witness in court. Somewhere along the way, time was found to operate a four hundred acre mixed farm, a one hundred seat restaurant and to obtain a licence as a flying instructor.
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