MALARIA, a disease that has shaped human society, settlement and history probably more than any other, is on the downward trend everywhere – globally, new infections are down 37%, and deaths have fallen 60%.
Governments, health organisations and scientists are accelerating the fight against the disease, particularly in Africa, where 90% of cases are concentrated. Thanks to improvements in prevention, diagnosis, treatment and surveillance, possibly for the first time in history, a world without malaria seems plausible.
Still, the disease is stubborn to eradicate, and has left behind it a long trail of resistant drugs, failed vaccines, and broken hearts.
Part of the reason is the remarkable adaptability of the Plasmodium parasite, which has eluded defeat time and time again. It has conquered quinine, chloroquine and sulphur as first-line drugs, and currently, the most promising vaccine – 28 years in the making – has been modestly successful, conferring only partial immunity against the disease in children.
A major hurdle in eliminating the disease is in one of the peculiarities of malaria infection. A number of studies have shown that many people who live in malaria-endemic areas — up to 60% of some sample populations — actually carry the parasite without showing symptoms, as the parasite “hibernates” in the body, eluding its immune responses.
Plasmodium falciparum infection has been shown to persist asymptomatically in semi-immune individuals for more than 18 months. These so-called asymptomatic carriers act as disease reservoirs, allowing malaria to circulate in the population.
The trouble is that finding the disease in asymptomatic patients requires serious scientific firepower. To get anywhere near finding most hidden cases, trained scientists and technicians need expensive and complicated tools called thermal cyclers, which help them recognise whether Plasmodium’s genetic material is present in a person’s bloodstream.
But that type of equipment and skills isn’t necessarily available close to patients in malaria-endemic regions of Africa, South Asia and Central and South America. As a result, the process often takes days.
But that’s about to change. GE has partnered up with Global Good, itself a collaboration between the Gates Foundation and Intellectual Ventures, and are developing a new paper-based test called a lateral flow assay (LFA), which uses a patient’s blood sample to detect malaria in asymptomatic carriers.
“We’re operating under the idea that if you can find those asymptomatic malaria carriers and treat them, then you could eliminate the disease from a region,” says David Moore, the laboratory manager of membrane and separation technologies at GE’s Global Research Center.
Like a pregnancy test from a pharmacy, the malaria LFA is designed to identify proteins made by the parasite that are present in the blood, and provides results within minutes. A positive result is indicated by a color change on the bioactive paper.
“Today, existing solutions tackle diagnosis in symptomatic patients, albeit sometimes inadequately, but miss infection in asymptomatic patients, resulting in the cycle of infection continuing,” wrote Matt Misner, a materials scientist and project leader working in Moore’s lab.
“We expect that the combination of these technologies will stack up to provide the performance necessary to make a real impact on the way malaria is treated. Additionally, when successful, we plan to adapt this diagnostics platform to target other infectious diseases that persist around the world.”
Says GE’s Moore: “Overall, we’re very pleased with the way things are progressing. So far, the results are promising and we’re encouraged by the data we’re getting back.”