Conventional techniques lack the potential to easily sample wider geographical areas and huge numbers of individuals. This often hampers real-world disease and parasite monitoring.
DNA. Image Credit: Billion Photos/Shutterstock.com
This can lead to patchy data that lack what scientists require to predict and mitigate outbreaks. In a new study reported in BioScience, researchers Jessica Farrell (University of Florida), Liam Whitmore (University of Limerick), and David Duffy (University of Florida) explain the potential of innovative molecular methods to overcome such drawbacks.
The researchers note that sampling of environmental DNA and RNA, or eDNA and eRNA, will enable scientists to better identify the presence of both human and wildlife pathogens. The eDNA and eRNA method works by collecting a sample (usually from an aquatic source), the genetic contents of which are then sequenced to uncover the occurrence and prevalence of pathogens.
The eDNA or eRNA offers scientists a timely picture of the disease spread, which “can help predict the spread of pathogens to nearby new and susceptible geographic locations and populations in advance, providing opportunities to implement prevention and mitigation strategies,” added the researchers.
During the COVID-19 pandemic, for example, scientists employed eRNA analysis of wastewater to trace large-scale outbreaks of disease and found that “wastewater detection of SARS-CoV-2 eRNA increased rapidly prior to medical detection of human outbreaks in those regions, with environmental virus concentration peaking at the same time or before the number of human-detected cases, providing advanced warning of a surge in infected individuals.”
This progressive knowledge will help limited and vital medical resources to be provisioned where they will be most required.
The advantages of eDNA and eRNA analysis are not limited to the detection of human pathogens. The researchers add that these tools could even help understand the presence and transmission of pathogens that hinder wildlife conservation efforts, for example, chelonid herpesvirus 5, the turtle-specific DNA virus.
The eDNA tracking of this pathogen might enable scientists to assess the spread of the disease—specifically, the idea that the virus is most often transmitted by “superspreader” individuals.
According to Farrell, Whitmore, and Duffy, these technologies have a bright future, “with the potential to vastly exceed traditional detection methods and the capacity to improve the detection and monitoring of aquatic pathogens and their vulnerable host species, including humans.”
Farrell, J. A, et al. (2021) The Promise and Pitfalls of Environmental DNA and RNA Approaches for the Monitoring of Human and Animal Pathogens from Aquatic Sources. BioScience. doi.org/10.1093/biosci/biab027.