Vector Competence of Eucampsipoda africana (Diptera: Nycteribiidae) for Marburg Virus Transmission in Rousettus aegyptiacus (Chiroptera: Pteropodidae)

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.

Isolation of infectious Lloviu virus from Schreiber’s bats in Hungary

“…It is not yet clear whether these bat flies may be acting as natural vectors or mechanical vectors for LLOV transmission or are simply dead-end LLOV spillover hosts. A recent article reported the unsuccessful infection of bat flies with MARV, ruling out the biological vector competence but still considered the possibility of mechanical transmission 47 . Our observations are in accordance with this recent report, since LLOV-positive ectoparasites were only retrieved from positive animals, suggesting the presence of the viral RNA in engorged parasites.…”

Ectoparasite and bacterial population genetics and community structure indicate extent of bat movement across an island chain

“…Published data on Rousettus bats and Eucampsipoda bat flies indicate similar patterns (Rajemison et al, 2017;Pawęska et al, 2021). It is also possible that bat flies may be experiencing weaker selection pressure than bats because the environment they experience as parasites is relatively stable compared to the environment that bats experience.…”