PT  - JOURNAL ARTICLE
AU  - Marina Voinson
AU  - Alexandra Alvergne
AU  - Sylvain Billiard
AU  - Charline Smadi
TI  - Stochastic dynamics of an epidemics with recurrent spillovers from an endemic reservoir
AID  - 10.1101/213579
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 213579
4099  - http://biorxiv.org/content/early/2017/11/03/213579.short
4100  - http://biorxiv.org/content/early/2017/11/03/213579.full
AB  - Most emerging human infectious diseases have an animal origin. Yet, while zoonotic diseases originate from a primary reservoir, most theoretical studies have principally focused on single-host processes, either exclusively humans or exclusively animals, without considering the importance of animal to human transmission for understanding the dynamics of emerging infectious diseases. Here we aim to investigate the importance of spillover transmission for explaining the number and the size of outbreaks. We propose a simple stochastic Susceptible-Infected-Recovered model with a recurrent infection of an incidental host from a reservoir (e.g. humans by a zoonotic species), considering two modes of transmission, (1) animal-to-human and (2) human-to-human. The model assumes that (i) epidemiological processes are faster than other processes such as demographics or pathogen evolution and (ii) that an epidemic occurs until there are no susceptible individuals left. The results show that during an epidemic, even when the pathogens are barely contagious, multiple outbreaks are observed due to spillover transmission. Overall, the findings demonstrate that the only consideration of direct transmission between individuals is not sufficient to explain the dynamics of zoonotic pathogens in an incidental host.