Biomarkers and Diagnostics

Detecting the pathogen by examining the host

Current diagnostics for infectious diseases rely on the infection being advanced enough that either

  1. the pathogen has replicated to high numbers and so can be easily detected, or
  2. the body begins to create distinct symptoms.

But what happens if the infection doesn’t cause distinct symptoms? Or if by letting the infection progress we dramatically reduce the survival rate?

These are the problems faced by those trying to combat some of the world’s most dangerous viral pathogens, such as Hendra and rabies virus. Bats show no symptoms of Hendra virus, horses can’t tell us they feel unwell until the symptoms start (by which time they may have infected humans), and human infections typically start with non-specific symptoms (fever, cough, sore throat, and tiredness).  Once rabies becomes symptomatic the infection has a 99% mortality rate.

By examining the host’s molecular response to these infections, we can identify new biomarkers to determine who is infected, even before symptoms develop. This will allows us to intervene earlier, decreasing both the transmission and mortality rate of these infections.

One class of host molecules with significant potential as disease biomarkers are microRNAs (miRNAs). These small (18-22nt), non-coding RNAs respond rapidly to changes in a biological system and can be easily found in biological fluids, meaning we can detect changes without having to sample infected tissues (particularly important for brain or heart infections). Our team has spent years understanding these molecules, and implementing advanced machine learning / artificial intelligence algorithms to identify miRNA signatures of infectious disease.
If you’re interested in learning more or collaborating with us, get in touch!

Relevant Publications

  • Farr RJ, Rootes C, Rowntree L, Nguyen T, Hensen L, Kedzierski L, Cheng A, Kedzierska K, Au G, Marsh G, Vasan S, Foo CH, Cowled C, Stewart C. Altered microRNA expression in COVID-19 patients enables identification of SARS-CoV-2 infection. PLoS Pathogens 17(7):e1009759. PLoS Pathogens.
  • Tribolet L, Kerr E, Cowled C, Bean AGD, Stewart CR, Dearnley M, and Farr RJ. 2020. MicroRNA Biomarkers for Infectious Diseases: From Basic Research to Biosensing, Front Microbiol, 11: 1197. PubMed
  • Cowled C, Foo CH, Deffrasnes C, Rootes CL, Williams DT, Middleton D, Wang LF, Bean AGD, Stewart CR, 2017. Circulating microRNA profiles of Hendra virus infection in horses. Sci Rep 7, 7431. PubMed
  • Stewart CR, Marsh GA, Jenkins KA, Gantier MP, Tizard ML, Middleton D, Lowenthal JW, Haining J, Izzard L, Gough TJ, Deffrasnes C, Stambas J, Robinson R, Heine HG, Pallister JA, Foord AJ, Bean AGD, Wang LF. 2013. Promotion of Hendra virus replication by microRNA 146a. J Virol 87, 3782-3791. PubMed