HEALTH

Two-hour test boosts HIV care in rural Africa

0402 hiv

A blood diagnostic kit that can detect infectious diseases such as HIV and hepatitis B in just two hours is helping to track and better treat diseases in resource-poor regions of the world.

The device - SAMBA (Simple AMplification Based Assay) - was developed by a team of Cambridge scientists headed by Dr Helen Lee, who says the device is robust, simple and precise.

"It's really quite simple; the patients come in and the sample is taken. And that then gets tested. Within 90 minutes you get the results. And so you can really decide whether their drug, their treatment is being effective or if they have developed resistance, whether they are infected or not infected. So really you can get a result in 90 minutes of an extremely complicated test," Lee told Reuters, adding, "Normally to do this type of testing it's done in a machine the size of a Mini [car], and we've reduced it to the size of a coffee machine that literally anyone can use."

More than ten years in development, the first iteration of the machine had to be completely re-designed to overcome environmental factors, such as dust and heat.

"The SAMBA I machine, which is the first generation of this machine, for two days it didn't work in Malawi because the temperature in the lab went to 38 degrees Centigrade. So we ended up having to redesign SAMBA II to widen the temperature, now it can go to 40 degrees Centigrade," said the University of Cambridge researcher.

The simple test uses a tiny drop of the patient's blood which is loaded into the machine and mixed with a combination of chemicals and reagents in a disposable cartridge that changes color if a virus is present in the blood or plasma sample. It also evaluates the viral load in a patient's blood, critical for determining the effectiveness of treatment.

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The invention solves a number of fundamental problems of infectious disease detection in remote and resource-poor areas. Primarily, the test can be carried out by personnel with minimal training.

Lee and her team demonstrated how the reagents and blood sample are loaded into the machine in separate, individually shaped compartments: "It needs to be so intuitive that when you open it [the machine] up and you put it in, there is only one way you can put it - you couldn't put it wrong. And so we have actually simplified the procedure in such a way that I always think that anyone who can cook can do it."

Each SAMBA machine can run four samples at a time, at a cost of 17 USD for each test. It runs on electricity but can be battery powered in case of energy outages.

Crucially, the test delivers accurate results without the need for reagent refrigeration thanks to innovative freeze-drying that allows the test kit not only to remain stable at room temperature but also withstand heat up to 55 degrees Centigrade.

"The reagents need to be so stable because it needs to be able to be transported in the truck, which often can go to 50 degrees Centigrade. And also it needs to be able to be stored at room temperature because there is no refrigerator or there is very little room for the refrigerator," said Lee.

Sub-Saharan Africa has for decades been the epicenter for HIV, the virus that causes Aids. Nearly three quarters of all people with HIV live there.

In Malawi, an estimated one million people were living with HIV in 2013 and 48,000 died from HIV-related illnesses in the same year, according to UNICEF. Every year around 10,000 children die of the virus, a number the agency says could be tackled by early diagnosis and better medical care.

Huge strides have been made in recent years in identifying and treating those with HIV. South Africa, with the world's largest HIV and Aids treatment program, has seen HIV-related deaths decline to 140,000 in 2014 from 320,000 in 2010, according to recent government figures.

However, in developing countries with isolated communities, treatment remains an uphill battle.

Lee said that SAMBA II is perfect for 'test and treat' facilities while the patients are on site, thereby eliminating the time gap between testing and when diagnosis results are ready.

"It's very important to me that the tests are done then and there, and the results are given to them then and there. And the appropriate treatment or counseling should take place in one trip."

Lee's spin-off company, Diagnostics for the Real World, has raised around 85 million USD in grants from organizations including the U.S. National Institutes of Health, the medical research charity The Wellcome Trust, the Children's Investment Foundation (CIFF) and UNITAID to help fund development of the device and key implementation in resource-poor regions of Africa. The company says the tests have been used to screen 40,000 people for HIV in Malawi, Uganda and a growing number of other sites.

On Thursday (June 9) Lee won the Popular Prize at the European Inventor Award organized by the European Patent Office, winning nearly two-thirds of the votes in an online poll. EPO President Beno��t Battistelli said: "The overwhelming public vote for Helen Lee recognizes her major contribution to the early detection and treatment of infectious diseases in areas most in need."