In a recent study published in Emerging Infectious Diseases, researchers reported the detection of Bombali virus (BOMV, of the genus Ebolavirus) ribonucleic acid (RNA) among three free-tailed Mops condylurus (Molossidae) bat species in Mozambique.
Study: Bombali Ebolavirus in bats Mops condylurus (Molossidae), Mozambique. Image credit: Rudmer Zwerver/Shutterstock
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Studies have reported six viral organisms of the genus Ebolavirus, including Sudan, Zaire, Bundibugyo, Bombali, Taï Forest and Reston), some of which have caused disease outbreaks with considerable mortality on the African continent.
BOMV was initially detected among free-tailed bat species of the Molossidae family, particularly in the bat species Chaerephon pumilus and Mops condylurus in 2016 in the Bombali district of Sierra Leone.
Two years later, BOMV was identified in the bat species Mops condylurus in Kenya and a year later, in Guinea. Studies have not reported BOMV-induced infections in humans, including people experiencing symptoms of febrile illness and residing in locations where Bombali virus has been detected in bats. BOMV is the only Ebola virus identified recurrently by polymerase chain reaction (PCR) between 2015 and 2019 and among bats located more than 5,000 kilometers apart.
The epidemiology of BOMV in bats Mops condylurus is not fully understood. Seasonal alterations in population-based and environment-based changes are key factors in the dynamics of infectious agent transmission in nature-based settings. For example, pulses of paramyxovirus, coronavirus, and Marburg virus have coincided with a seasonal increase in juveniles among bats.
About the study
In the present study, the researchers detected Bombali virus RNA among three female Mops condylurus bats captured in Mozambique at a site located toward the southeast of the bats’ geographic distribution.
In May 2015, 54 species of Mops condylurus bats living in buildings in Inhassoro district, southeastern Mozambique, and other bats (n = 211 from 10 other bat species) were sampled , who reside mainly in caves. All samples were screened for viruses belonging to the Coronaviridae, Paramyxoviridae, and Astroviridae families. RNA was extracted from the samples and subjected to reverse transcription PCR (RT-PCR) analysis.
Complementary deoxyribonucleic acid (DNA) was screened using three assays targeting the large (L) protein gene of the Filoviriridae family, and the products of the PCR analysis were sequenced. The maps were generated using data obtained from the International Union for Conservation of Nature Red List website and Natural Earth. The phylogenetic analysis was performed based on transversion plus gamma evolutionary modeling. A maximum likelihood tree was generated from partial nucleotide sequences (587 base pairs) of the L gene of certain filoviruses.
results
The study’s findings supported the detection of Bombali virus south of the geographic range of Mops condylurus bats, a known residential location of the bat species. Partial sequencing of the L gene showed that BOMV genomic sequences identified in bats from Mozambique were closely associated with sequences documented among bats from Kenya, Guinea and Sierra Leone.
The virus was detected in three bats in Guinea between May 2018 and March 2019. In Sierra Leone, the virus was identified in an adult female in May 2016. In Kenya, the virus was detected in an adult female on May 2018 and two adult females in May 2019. In Mozambique, the virus was detected in three females in May 2014.
Although the results were obtained from short genomic sequences (587 base pairs), they indicated a strong relationship between M. condylurus and BOMV bats throughout their geographic distribution. BOMV was only detected in female bats, with no differences between adult and subadult populations. The team captured most BOMV-positive bats in daytime roosting regions occupied by livestock or humans.
Conclusions
Overall, the findings of the study supported the suspicion that Mops condylurus bats play a role in maintaining BOMV. Neither Bombali virus nor any other species of ebolavirus had been identified in humans in Mozambique, highlighting that the study’s findings should not be taken as evidence for a mass warning to individuals who flourish in the local community. Still, they should catalyze the initiation of future studies and continued surveillance efforts.
Further research should emphasize other members of the bat family Molossidae, as Bombali virus was first documented in Chaerephon pumilus, a part of the bat family that is often roosted in synanthropic sites and therefore , gives rise to propagation opportunities. Using a unified One Health approach (i.e. multi-sector, trans-disciplinary and collaborative) can prevent future disease outbreaks, promote sustainable human community development and protect bats with important functional roles in various ecosystems