Infectious diseases

A research team in Germany is exploiting the speed, sensitivity and stability of RPA and RT-RPA to develop a fully mobile suitcase lab platform that can be used for the field-based diagnosis of some of the world’s most devastating diseases, including Ebola1, Dengue2 and Chikungunya viruses as well as Visceral Leishmaniasis.

Dr Ahmed Abd El Wahed’s team at the Georg-August-University in Goettingen says that its RPA-based point-of-need tests are as sensitive and specific as laboratory PCR-based detection assays, but require no sophisticated equipment, and provide results in just 3-10 minutes.

“RPA has proven to be a truly enabling, open platform that has allowed us to develop a completely new generation of transportable, easy-to-use, fast and highly sensitive assays that will meet the criteria for WHO screening initiatives targeting diseases elimination including malaria and leishmania,” comments Dr Abd El Wahed. “The dried RPA reagents are stable over a number of months, and testing is highly reliable. The RPA assays are also far more sensitive and specific than current non-amplified lateral flow tests or lab-based ELISAs. The suitcase laboratory tests that we have already developed are proving ideal for resource-lacking field settings where sending samples off to a central laboratory and waiting days for the results just would not be feasible. Our latest funded project is to develop a rapid assay as part of a malaria detection program in Nigeria.”

It’s important to take the time to develop the right primer combinations that will work with the desired assay, he continues. “Once you have designed the optimum RPA primers, the assay is completely straightforward, user-friendly, and works faultlessly every time. We are using the technology with portable devices that have integrated touch screens, so that you can see the amplification curve in real time, but you can also use RPA with many different types of flow system. TwistDx has been an ideal partner to help us develop our tests for use in the field.”

The Göttingen team, together with researchers at Institute Pasteur de Dakar, the University of Stirling, Cairo University and icddr,b has to date applied the RPA platform to develop screening tests for Ebola, Dengue and Leishmania, as well as for Chikungunya virus, H5N13, foot and mouth, and lumpy skin disease virus in cattle. Dr Abd El Wahed maintains that the RPA-based tests will be ideal for use as a screening tool in the event of disease outbreaks, as part of disease screening and elimination programs, and at airports and other borders and or sites of animal importation to prevent cross-border disease spread.

1http://www.eurosurveillance.org/images/dynamic/EE/V20N44/art21289.pdf
2 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129682
3 http://www.sciencedirect.com/science/article/pii/S016609341500244X