Abstract:
This study aimed to determine the vector competence of bat-associated nycteribiid flies
(Eucamsipoda africana) for Marburg virus (MARV) in the Egyptian Rousette Bat (ERB), Rousettus
aegyptiacus. In flies fed on subcutaneously infected ERBs and tested from 3 to 43 days post infection
(dpi), MARV was detected only in those that took blood during the peak of viremia, 5–7 dpi.
Seroconversion did not occur in control bats in contact with MARV-infected bats infested with bat
flies up to 43 days post exposure. In flies inoculated intra-coelomically with MARV and tested on
days 0–29 post inoculation, only those assayed on day 0 and day 7 after inoculation were positive
by q-RT-PCR, but the virus concentration was consistent with that of the inoculum. Bats remained
MARV-seronegative up to 38 days after infestation and exposure to inoculated flies. The first filial
generation pupae and flies collected at different times during the experiments were all negative by
q-RT-PCR. Of 1693 nycteribiid flies collected from a wild ERB colony in Mahune Cave, South Africa
where the enzootic transmission of MARV occurs, only one (0.06%) tested positive for the presence
of MARV RNA. Our findings seem to demonstrate that bat flies do not play a significant role in the
transmission and enzootic maintenance of MARV. However, ERBs eat nycteribiid flies; thus, the
mechanical transmission of the virus through the exposure of damaged mucous membranes and/or
skin to flies engorged with contaminated blood cannot be ruled out.
