| dc.description.abstract | Ebola virus (EBOV) has caused several outbreaks as the consequence of spillover events
from zoonotic sources and has resulted in huge death tolls. In spite of considerable
progress, a thorough know-how regarding EBOV adaptation in various host species and
detailed information about the potential reservoirs of EBOV still remains obscure. The
present study was executed to examine the patterns of codon usage and its associated
influence in the adaptation of EBOV to potential hosts that dwell in Africa, the origin
of the viral outbreaks. Correspondence analysis (CA) revealed that the codon usage
signature in EBOV is a complex interplay of factors including compositional bias and
natural selection, with the latter having a more pronounced impact. Low codon usage
bias in EBOV indicates a flexibility of the viruses in adapting to diverse range of hosts with
different codon usage architectures. EBOV adaptation in potential hosts, as estimated
by codon adaptation index (CAI) and relative codon deoptimization index (RCDI),
revealed that the viruses were relatively better adapted to African primates than other
mammals examined, which might account for the high fatality rate of primates owing to
EBOV infection. Bats have been speculated as natural reservoirs of EBOV. In the present
analysis it was interesting to note that EBOV displayed lower degrees of adaptation,
as estimated by CAI and RCDI, with bats in comparison to the primate hosts. Lower
degrees of adaptation might contribute to long-term co-existence and circulation of the
viral pathogens in bat populations. Codon usage patterns of EBOV isolates associated
with different outbreaks varied significantly, with discrete patterns between the West
and Central African isolates. Additional evolutionary analyses indicated that the West
African Epidemic began with an initial spillover infection and there was more than one
population of EBOV circulating in the natural reservoir in the Democratic Republic of the
Congo. The present study yields valuable information regarding the possible circulation
of EBOV in various African mammals. | en_US |
