How African Scientists Are Testing Cheaper, Faster Ways To Test For Malaria, Pregnancy, HIV SuccessDate Released: Wed, 14 November 2018 10:34 +0200
Longer-lasting and more cost-effective ways of testing for pregnancy and whether HIV treatments are working effectively, as well as checking for the top two strains of malaria, are being tested by scientists at a South African university. These could ultimately help save lives in emerging countries, they believe.
Testing for malaria and the efficacy of a HIV treatment have traditionally been very difficult to do in Africa without a blood test – which are expensive and require a trained nurse and a trip to an often distant clinic.
But scientists in South Africa are testing a way to do this with widely prevalent urine dipsticks, with a new disruptive way of creating the more advanced and cheaper active ingredients needed for these tests.
"We have made aptamers, which behave like antibodies in a diagnostic test, but they are cheaper and last longer," said Professor Janice Limson, director of the Biotechnology Innovation Centre at Rhodes University in Grahamstown. The tests are being done at these laboratories with support from Unicef's Global Innovation Centre.
Urine dipstick tests have been around for decades and are ripe for disruption, they are demonstrating.
"The business end of the dipstick is the antibody. We are replacing the antibodies with something that is cheaper and lasts longer, which is really important for remote areas," Limson told me. This is especially helpful for the HIV test, which checks for the number of the key CD4 blood cells which indicate if the treatment plan is being effective or if the HIV strains have mutated to resist the medication. Previously such a test would require blood tests, which can only be performed by nurses and are very expensive.
The malaria tests are significant in that they "can distinguish between two different types of the most common species of malaria: Plasmodium falciparum and Plasmodium vivax," says Limson, who is also the prestigious DST/NRF South African Research Chair in Biotechnology Innovation and Engagement.
Unicef Senior Adviser on Innovation Tanya Accone says these tests are a breakthrough.
“This is a breakthrough approach because these diagnostic tests use completely new biological materials to the existing tests," she told me. "This means the tests could cost half as much to produce and will be able to be distributed and used by women in remote locations because, unlike existing tests, these biomaterials are not sensitive to temperature and humidity."
Due to the cost of blood test and difficulty of travelling to a clinic, many people receiving antiretroviral (ARV) drugs have to wait for up to a year for their blood to be tested to see if the medication is working.
"The number of living cells in a HIV patient's blood is a very important metric of overall health," Dr Ron Fogel from Rhodes Biotechnology Innovation Centre told me. "When people have been on HIV medication for a long time, it starts losing effectiveness because the different strains of HIV in a patient are becoming resistant. The way that you track that is by the CD4 count. As HIV numbers increase, the CD4 starts dropping, so that's when you know to start a new treatment."
The new test will be able to give feedback on CD4 count much quicker.
For the pregnancy dipstick, the Rhodes team are able not only to measure the presence of the beta-hCG (b-hCG) hormone which indicates pregnancy, but how much of it. The benefits of this are an early warning system for possible complications, says Limson.
"The same test can be semi-quantitative, it's not just saying you are pregnant. Because they can monitor b-hCG levels, it can be used as a tool. In normal pregnancy they should increase in first few weeks. The b-hCG levels can be an early indicator or raise a red flag of potential high-risk pregnancies, which can indicate whether the mother needs better or different care, especially with multiples, from twins to triples and quadruplets."
The three urine dipsticks are currently in the laboratory testing phase, but as Accone says, are already a breakthrough. "This work has game changing implications for emerging markets not only because of potential cost savings, but also the potential to produce these diagnostics domestically instead of importing them," she says.