Abstract:
The Egyptian fruit bat, Rousettus aegyptiacus, is currently regarded as a potential reservoir host for Marburg virus (MARV).
However, the modes of transmission, the level of viral replication, tissue tropism and viral shedding pattern remains to be
described. Captive-bred R. aegyptiacus, including adult males, females and pups were exposed to MARV by different
inoculation routes. Blood, tissues, feces and urine from 9 bats inoculated by combination of nasal and oral routes were all
negative for the virus and ELISA IgG antibody could not be demonstrated for up to 21 days post inoculation (p.i.). In 21 bats
inoculated by a combination of intraperitoneal/subcutaneous route, viremia and the presence of MARV in different tissues
was detected on days 2–9 p.i., and IgG antibody on days 9–21 p.i. In 3 bats inoculated subcutaneously, viremia was detected
on days 5 and 8 (termination of experiment), with virus isolation from different organs. MARV could not be detected in
urine, feces or oral swabs in any of the 3 experimental groups. However, it was detected in tissues which might contribute
to horizontal or vertical transmission, e.g. lung, intestines, kidney, bladder, salivary glands, and female reproductive tract.
Viremia lasting at least 5 days could also facilitate MARV mechanical transmission by blood sucking arthropods and
infections of susceptible vertebrate hosts by direct contact with infected blood. All bats were clinically normal and no gross
pathology was identified on post mortem examination. This work confirms the susceptibility of R. aegyptiacus to infection
with MARV irrespective of sex and age and contributes to establishing a bat-filovirus experimental model. Further studies
are required to uncover the mode of MARV transmission, and to investigate the putative role of R. aegyptiacus as a reservoir
host.
