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angradillo t1_ja7pyt6 wrote

Likely transfer from fruit bats in or around the Kitum Cave region in then-Zaire (which gives its name to the most dangerous case-death strain) and modern Congo/Gabon. High monkey populations around this area function as a reservoir for Ebola Zaire.

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Allfunandgaymes t1_ja8d08h wrote

Ebola (or ebola hemorrhagic fever) is a zoonotic viral disease which has resurfaced multiple times in separate "spillover" events from its animal reservoir species, which likely includes bats and nonhuman primates. There's more than one ebolavirus, and multiple strains have been implicated in outbreaks, with the Zaire ebolavirus thus far being the most deadly.

Even though ebola can be transmitted from one human to another, humans are not a reservoir species for ebolavirus due to the fact that it a) does not remain indefinitely latent in the human body b) is relatively hard to transmit in that it requires direct physical exposure to infected material and c) it is very frequently fatal. This is why outbreaks have been relatively sporadic with no global spread.

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PHealthy t1_ja8fy3d wrote

Given the immune environment of bats, it's thought that most hemorrhagic fevers are evolved from them.

https://www.nature.com/articles/s41586-020-03128-0

There has certainly been a lot of press around Kitum cave but there are earlier recorded outbreaks and the pinpoint origin really can't be said definitively since viral studies were pretty cutting edge 50 years ago.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4166725/

https://academic.oup.com/trstmh/article/109/6/366/2461644

Of course, just saying it likely originated from bats doesn't really give the whole current story, there are many mammals that are thought to act as reservoir species so the cat is out of the bag...

https://www.science.org/doi/10.1126/science.1172705?url_ver=Z39.88-2003

https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004815

Took a little digging but Dorothy Tovar provided some great bat facts in this COVID AMA:

https://www.reddit.com/r/science/comments/ezstsw/science_discussion_series_the_novel_coronavirus/

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babar90 t1_ja9wu6c wrote

Search for https://www.ncbi.nlm.nih.gov/nuccore/?term=Ebolavirus%5Borganism%5D+AND+bat on genbank you'll find two batches of bat ebolavirus sequences: one 2019 paper https://pubmed.ncbi.nlm.nih.gov/31002301/ sequencing full Bombali ebolavirus genomes from bats, this study is considered trustful and indicates a bat origin of Bombali. This is also confirmed independently by some Predict sequences such as https://www.ncbi.nlm.nih.gov/nuccore/MT929359.1

And another 2005 paper https://www.nature.com/articles/438575a using nested PCR to obtain short partial Zaire ebolavirus (the genuine Ebola) sequences. This hasn't been replicated since 2005, this paper is not considered trustful.

There is a similar nested PCR story for Reston ebolavirus https://virologyj.biomedcentral.com/articles/10.1186/s12985-015-0331-3 but they didn't bother to upload the sequence to genbank..

Still Marburg (a distant filovirus) also has a clear bat origin.

Together with the serological studies and the lack of other putative reservoir it means that fruit bats are still our best guess.

But the truth is that we don't know for sure.

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