Cell-free diagnostics for the surveillance of livestock viruses

The overall aim of this project is to build a liquid phase cell-free diagnostic test for livestock viruses.

The Idea

Cell-free paper based diagnostics like those developed by Pardee et al. for the detection of Zika and Ebola viruses, are low-cost, point-of-use and highly stable, and are therefore poised to revolutionise diagnostic testing in resource-limited settings across the Global South.

Livestock viruses such as Foot and Mouth Disease (FMD), Newcastle Disease (ND), and Bovine Respiratory Syncytial Virus (BRSV) are an emerging threat to global food security, farmers’ livelihoods, and national economies. In many countries, livestock diseases are endemic; meaning they are impossible to eradicate due to uncontrollable transmission between domestic and wild animal populations. Implementation of disease surveillance programmes is the most effective way of controlling disease-related losses, since rapid detection of disease enables timely action to be taken, preventing further spread of the disease. The greatest barrier to the implementation of disease surveillance programmes in low-middle income countries (LMICs) is the lack of affordable, point-of-use diagnostics.

In the proposed project, we outline how we plan to firstly replicate the work of Pardee et al. 2016 in detecting a fragment of the Zika virus genome with an RNA-based toehold switch-lacZ gene circuit, in a cell-free system. Secondly, we will adapt this circuit to detect a viral fragment from a livestock virus – the specific virus will be selected upon consultation with disease experts at the University of Cambridge and the Pirbright Institute. Adaptation of the circuit will involve in silico design of RNA amplification circuits and novel toehold switches, which activate in the presence of amplified viral trigger RNA, to express LacZ, an enzyme which produces a visible colour change.