The stimulus
might be stress, co-infection and change in food sources and
pregnancy as displayed in vivo and in vitro investigations[20,21].
This hypothesis describes the infrequent nature and periodicity of
EHF in Africa. Mammalian species including NHP vulnerable to
infection are considered as the dead end hosts. The probabilities of
seasonal outcome on introduction of ebola virus infection have also
been proposed[22,23]. The future studies require consideration of the
level of infections of ebola viruses in fruit or insectivorous bats in
areas prevalent for these viruses. Issues such as virus pathology and
perseverance in bats, conceivable activation process of insistent virus
and possible transmission routes required to be monitored by field
and experimental investigations. Other possible reservoir species and
a role for potential augmenting hosts, particularly after the detection
of Reston ebola virus in pigs in the Philippines should also be
investigated[24].