International study yields model to better predict, dissect infectious diseases

An international effort has created a new model for the identification and study of hosts critical to the spread of infectious diseases.

Such hosts are known as superspreaders, but their superpower is their role in epidemics. Not every infected person has the same potential to damage. Take the 2014-2016 Ebola epidemic in Western Africa, where researchers reported that just 3 percent of patients led to more than 60 percent of infections. Those individuals represent the superspreader element, a role present in other diseases as well.

The epidemiological models currently used for these diseases have proven unable to deal with such diseases’ behavior patterns. They fail to account for variation in host competency — the capacity for one human or animal host to cause new infections — and leave a knowledge gap behind.

“The relationship between physiology and behavior in individual hosts determines the dynamics of how infectious disease emerges and spreads in the community,” said Lynn Martin, a professor at the USF Health College of Public Health and lead author of this study. “Individuals are not the same – and distinguishing how they differ within the context of host-parasite interactions is critical. This new framework might help us better target vaccinations, hygiene and other measures to those individuals most likely to influence the spread of infections during epidemics.”

The new test tracks competency through four stages: exposure to, susceptibility for, suitability for and transmissibility of infectious organisms. It concludes that their combination is what determines a host’s role in disease circulation. The test has already been used to investigate how host body size also might affect disease influence.