See these files I think useful for you.

1) Could a special immune system help protect bats from Ebola?

https://www.mpg.de/9403928/ebola-bats

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15 sept. 2015 - Bats frequently come into contact with infectious diseases, but ... The research could also be significant in the fight against viral ... The animals seem to be able to fight off the pathogens without becoming ill themselves.

2) Ebola Virus - Baylor College of Medicine

https://www.bcm.edu/departments/.../ebola-virus

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Ebola viruses cause a severe illness known as Ebola hemorrhagic fever that can ... which may allow enough time for the body's immune system to fight off the virus. ... Infected bats can transmit the virus to monkeys and apes, so humans can ...

3) Bat's immunity may hold key to preventing future Ebola ...

theconversation.com/bats-immunity-may-hold-key-to...

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15 oct. 2014 - Bats can harbour viruses such as Ebola and don't display clinical signs of disease. ... Ebola shuts off the immune response to the virus, resulting in rapid viral ... Two trials signal pivotal point in fight against the AIDS epidemic.

Thanks Nouhoum for your links. If you come across a paper with regards the first link drop me a line. Best wishes!

Hi Diego, my little contribute to this discussion is related to  a recent pubblication which I add as link.

I know that is a partial explanation and more is only a part of  the matter but to me seems intriguing.

In the meanwhile I whish happy new year.

See you

http://elifesciences.org/content/elife/4/e11785.full.pdf

It seems that in co-evolving with the host species (flying foxes, etc.), it seems that bat innate immune sensing is not inactivated by VP35 of Ebola and/or type I IFN responses are not blocked by VP24 or VP40. This is likely the same level of co-existence of African Swine Fever Virus in wild boar/warthogs, Nipah and Hendra in fruit bats, etc.

O'Shea et al "hypothesize that flight, a factor common to all bats but to no other mammals, provides an intensive selective force for coexistence with viral parasites through a daily cycle that elevates metabolism and body temperature analogous to the febrile response in other mammals. On an evolutionary scale, this host–virus interaction might have resulted in the large diversity of zoonotic viruses in bats, possibly through bat viruses adapting to be more tolerant of the fever response and less virulent to their natural hosts." 

http://dx.doi.org/10.3201/eid2005.130539

Thank to you all, I agree with all of your points of views, the papers that you have shared are great and full of details, nevertheless further studies will be require to know insight out the role of NPC1 with possibly inclusion of other types of bats in different settings. More than 60 viruses that can infect human have bats as reservoirs, so possible interactions among them might not be excluded.

Flight plays a major role in that question, so future investigation comparing the immune response of bats at their rest time versus after flying. Unlocking how bats are resistant to Ebola will open new windows on how to prevent and treat this deadly disease.

It's very doubtful NPC1 will prove by itself to explain it. The amino acid sequence homology is too high. Same with VP35 when you actually do the  MSA. The interacting residues (see Jeffers et al) in GP1, however are less conserved (15/17=88.2%) and it may be a simple single nonsynonymous change to explain a part of it. 

It certainly has been the subject of a lot of discussion, without a definite conclusions. This  Plos One paper that discussed a number of possible factors is worth reading (https://www.researchgate.net/post/Why_bats_seem_to_be_able_to_fight_off_Ebola_virhttp://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1003651)

 For an extensive survey on bats and viruses see : 

Bats and viruses : a new frontier of emerging infectious diseases / edited by Lin-fa Wang and Christopher Cowled. 2015, John Wiley & Sons, Inc.

Great question and discussion! Bob Grant at UCSF/GIVI did a great piece on this topic in the Dec 2014 issue of The Scientist. Bats are able to harbor diverse pathogens, including Ebola, Marburg, SARS, and MERS viruses. In addition to those already pointed out in this discussion, it is possible that the bat's hyperkinetic physiology - as if they are continuously running a fever - also contributes to its ability of keeping an otherwise lethal infection at bay. Geza Harczi above also alluded to this. Also, the metabolic demands of flight might have led to the evolution of heightened DNA damage-repair pathways in bats.  http://www.the-scientist.com/?articles.view/articleNo/41537/title/Lurking-in-the-Shadows/

Hi Diego,

FYI

I found a recent paper which tried to reply to the question, here is the link with full details

http://www.pnas.org/content/early/2016/02/17/1518240113.full.pdf

Thanks, Diego, this is very interesting. An odd difference between alpha and beta IFN. In chickens, constitutive activation of IFN lambda was found to be lethal by two weeks of age (essentially after the yolk-sac was resorbed). I wonder how IFN alpha expression in the gut does not affect uptake of nutrients.  Weird.  Thanks again.

Ebola virus : EBOV, formerly designated Zaire ebolavirus) is one of five known viruses within the genus Ebolavirus. Four of the five known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals, known as Ebola virus disease (EVD). Ebola virus has caused the majority of human deaths from EVD, and is the cause of the 2013–2015 Ebola virus epidemic in West Africa,[2] which resulted in at least 28,616 suspected cases and 11,310 confirmed deaths.

regards

https://www.mpg.de/9403928/ebola-bats

@ Diego Mpia Elenge

Please have a look at the following PDF attachment.

Thanks!

Another good summary on this topic is:

Lisa A. Beltz (2018). Bats and Human Health: Ebola, SARS, Rabies and Beyond, John Wiley & Sons