Fault Lines of Human-Animal Interaction May Aid in Predicting Next Infectious Disease Pandemic

As global health researchers work to predict when and where the next big infectious diseases will emerge, the authors of one new study suggest that the best places to observe emerging viruses are along the “fault lines” of interaction between humans and animals.

Although the viruses highlighted in some epidemics, such as the Ebola virus outbreak that began in West Africa in 2014 and the Zika virus outbreak that emerged in South America in 2015, involved pathogens that were identified decades ago, the 2003 outbreak of severe acute respiratory syndrome (SARS) involved a newly identified pathogen. New or old pathogen aside, in each of these high-profile outbreaks, global health officials had not predicted the epidemics and even the most rapid response efforts were not fast enough to squash them at the onset.

Still, the World Health Organization (WHO) works with global public health experts to identify emerging diseases and attempts to predict the next big epidemics and create strategies to address such threats. WHO’s Department of Pandemic and Epidemic Diseases, for example, monitors threats such as pandemic influenza, yellow fever, and cholera, creating readiness strategies and stockpiling vaccines in preparation for the next big outbreaks. Despite all these efforts, could even more work be done to better predict pandemics?

The authors of a new study, published in the open access journal Open Biology, argue that current efforts to predict the next pandemic outbreaks just don’t work. They cite new ventures such as the Global Virome Project started in 2016, a cooperative scientific initiative to reduce the potential for harm from future virus outbreaks. Although the project is still in its nascent stages, it’s aim is to identify and characterize 99% of the zoonotic viruses that may cause the next human epidemics. The study’s authors, however, contend that such an effort is unlikely to spot the next viral threat, as there about 4400 recognized viruses and millions more yet to be discovered in the virosphere.

Instead, to better study virus emergence, the authors suggest that more accurate predictions may come from studying ecological “fault lines” of human—animal interface. “Examples of the fault lines we refer to are where humans and animals meet,” said study co-author Jemma Geoghegan in an interview with Contagion^®. “For example, during deforestation, at live animal markets, and hunting wild animals.”

The study notes that it is at these lines that heightened contact occurs between humans and animals, raising the chance for cross-species virus transmission events through wildlife trade and consumption. Researchers cannot predict whether an animal virus will develop the mutations to infect humans; however, the authors suggest we may better spot emerging diseases by conducting virological surveillance at such fault lines of human encroachment.

“The inconvenient truth for all those working in the realm of disease emergence is that the vastness of the unknown virosphere and the diverse range of viruses that have achieved endemic transmission in humans means that any attempt to predict what virus may emerge next will face substantial, and probably crippling, difficulties,” write the authors. “In light of this, we suggest it may be of more benefit to public health to target, via surveillance, the fault-line of disease emergence that is the human-animal interface, particularly those shaped by ecological disturbance.”