Abstract:
Ebola virus disease (EVD) is a zoonotic disease (i.e. disease that is spread
from animals to people). Therefore human beings can be infected through direct contact
with an infected animal (fruit-eating bat or great ape). It has been demonstrated
that fruit-eating bats of pteropodidae family are potential reservoir of EVD. Moreover,
it has been biologically shown that fruit-eating bats do not die due to EVD and bear the
Ebola viruses lifelong. We develop in this paper, a mathematical model to assess the
impact of the reservoir on the dynamics of EVD. Our model couples a bat-to-bat model
with a human-to-human model and the indirect environmental contamination through
a spillover process (i.e. process by which a zoonotic pathogen moves (regardless of
transmission mode) from an animal host (or environmental reservoir) to a human host)
from bats to humans. The sub-models and the coupled models exhibit each a threshold
behavior with the corresponding basic reproduction numbers being the bifurcation
parameters. Existence of equilibria, their global stability are established by combining
monotone operator theory, Lyapunov–LaSalle techniques and graph theory. Control
strategies are assessed by using the target reproduction numbers. The efforts required
to control EVD are assessed as well through S-control. The spillover event is shown to
be highly detrimental to EVD by allowing the disease to switch from bats to humans
even though the disease was not initially endemic in the human population. Precisely,
we show that the spillover phenomenon contributes to speed up the disease outbreak.
This suggests that the manipulation and consumption of fruit-bats play an important
role in sustaining EVD in a given environment.
