Ebola epidemic likely stemmed from contact with insectivorous bats
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The ongoing Ebola outbreak may have originated from contact with infected bats, according to recent data published in EMBO Molecular Medicine.
Researchers from the Robert Koch-Institute in Berlin examined possible sources of transmission in the index village of Meliandou, Guinea, through wildlife surveys and interviews with residents. The investigators hypothesized that the initial infection of a male, aged 2 years, came from either the hunting of fruit bats or, more likely, contact with a nest of insectivorous free-tailed bats.
Because no decline in local populations was observed, larger mammals and wildlife were eliminated as sources of infection. This is supported by the early infections of children and women, as opposed to adult men who typically would be the first to have contact with infected game meat as a result of their role as hunters.
Bat hunting, however, was found to be very common among residents of the area. Although fruit bats are more prevalent and sought for their meat, researchers wrote it was unlikely they were the point of transmission when considering there were no hunters in the index patient’s family.
The most promising explanation comes from interviews with Meliandou locals who described a hollow tree near the index patient’s home that children frequently played in and around. Although the tree had since burned down, villagers reported that it had housed a large colony of insectivorous free-tailed bats. Deep sequencing of a short 16S mitochondrial DNA fragment recovered from soil and ash samples near the tree revealed that the bats were most likely of the Mops condylurus species.
Researchers also captured various species of bats around Meliandou and two nearby regions. PCR-testing of these recovered samples did not detect signs of Ebola virus infection, but three of the captured species, M. condylurus, Eidolon helvum and Hypsignathus monstrosus, had been reported as Ebola virus positive in previous studies.
“Our findings support the idea that bats were the source of the current Ebola virus disease epidemic in West Africa and enlarge the list of plausible reservoirs to include insectivorous bats,” the researchers wrote. “Future sampling campaigns, in-depth serological studies and modeling efforts should take into account the possibility that fruit bats may not always be the ultimate source of Ebola virus disease outbreaks.”
Disclosure: The researchers report no relevant financial disclosures.