The Center for Tropical Research has received, in partnership with Dr. Rick Schoenberg, chair of the Department of Statistics at UCLA, an NSF-funded grant to apply Hawkes point process models to characterize how infectious diseases, including ebola, spread. These models have typically been used in seismology to accurately predict earthquakes and their aftershocks, and although they are often referred to as epidemic-type models, have rarely been applied to actual disease epidemics.

A good test of these models are long-term data on infectious diseases, where it appears as if the disease has been eradicated, only to have it spuriously pop up again in a host population some time later. These host populations could be human or wildlife.

Ebola disease is caused by a virus that has periodically emerged in human populations in Africa (and most recently crossing continental borders in a 2014 outbreak) for the last 40 years. There have been at least 25 outbreaks of ebola since 1976, and these outbreaks cover a wide geographic range, from West to Central Africa. Our current work seeks to understand why outbreaks occur when and where they do.