Let's get something out of the way first: it's Eh-bowl-a, with an emphasis on the middle syllable.

If only other facts about the virus were that easy to clear up. Unfortunately, concerns and fears have rapidly outstripped knowledge. Despite the public fears, we do know a fair amount about Ebola and its activities, and what we know tells us a lot about the prospects for treatments and vaccines.

To get a clearer picture of what we know about the virus and the illness it causes, we've spent some time diving into the papers that describe the virus' biology. We also called up Vincent Racaniello, a researcher at Columbia University's Medical School and host of the This Week in Virology podcast, who helpfully provided us with a professional's perspective on Ebola.

A simple virus

In some ways, Ebola is remarkably average. Appearance-wise, it forms an unusually long and flexible filament—although other viruses are filamentous, Racaniello was hard pressed to think of any that are quite as bendy as Ebola. On the genetic level, however, things look fairly mundane. Its genome consists of a single linear strand of RNA that's about 19,000 bases long. It contains only seven genes, most of which encode proteins that give the virus its structure. (For comparison, a typical herpes virus is over 10 times larger and carries over 35 genes.) "It's a pretty basic complement of proteins—all RNA viruses need the same ones," Racaniello said.

One gene, called NP, encodes a protein that coats the RNA and keeps it packaged inside the virus particle. Two other proteins, VP24 and VP40, coat the inside of the membrane that forms the outer layer of the virus—membrane that was originally produced by an infected cell.

Beyond those proteins, things get more interesting. The only genetic material that can be duplicated by the enzymes carried by cells is DNA. But, as we noted, Ebola's genome is encoded by RNA. Viruses handle this discrepancy in two ways. Some of them, like HIV, encode an enzyme that copies RNA into DNA, and additional copies of the virus are then made from this DNA. Ebola virus takes the alternative route: its genome encodes a protein that can copy RNA into RNA.

This gene (creatively called the polymerase, or L) is the largest one carried by the virus. The viral polymerase performs a double role in that it also copies the viral genome into messenger RNAs that are then translated into proteins by the infected cells. So, without a working polymerase, you can't make any proteins inside an infected cell. For this reason, every copy of the virus has a working polymerase protein packed inside.

There's a second protein that's involved in making messenger RNAs and copies of the virus—it tells the polymerase where to start copying. It's called VP 35, and it's also packed inside the virus when it's sent off to infect new cells.

This all may sound rather exotic, but it's actually quite common. The group of negative-strand RNA viruses, including Ebola, is quite large. Among human pathogens alone, it includes influenza, measles, mumps, rabies, and hantaviruses. So while this aspect of Ebola is interesting, it's anything but exotic, and it certainly doesn't explain the disease's behavior.

Immune shutdown

Another gene that's somewhat more intriguing is called VP35. This protein functions to help the virus evade an immune response. The body's immune system consists of two parts that work cooperatively. The one we mostly learn about, acquired immunity, involves antibodies and other specialized receptors that recognize specific infectious agents. Acquired immunity is the whole reason vaccines work. But this takes a while to get up to speed when a pathogen has never been encountered before.

To help protect the body at that point in the infection, cells rely on what's called the innate immune system. This isn't specific to any particular pathogen, but instead this recognizes features that are common to many pathogens, like sugars or lipids made by bacteria. Many viruses carry a protein that helps shut the innate immune system down, and Ebola is no exception. That task is handled by VP35.

"Ebola happens to have a protein that antagonizes innate immunity, and most viruses must have one of those, so it's not really unusual," Racaniello told Ars. "The innate response is so powerful that, if a virus doesn't have something to counter it, it's going to be wiped out pretty quickly."

In Ebola's case, VP35 does several things to tone down innate immunity. It binds to and inactivates some proteins involved in this response. It also blocks a branch of the innate immune system that recognizes double-stranded RNA. While these are a necessary part of the replication of single-stranded RNA viruses, they're not normally produced in the cell in any great quantities, so it's a useful way of identifying when a viral infection may be in progress. Research suggests that VP35 handles its task via a very simple route: it binds to double-stranded RNA and hides it from the innate immune system.

Partly as a consequence of this, the innate immune system doesn't trigger the production of immune signaling molecules called interferons. These interferons normally help marshal specialized immune cells and can boost the adaptive immune response.

On the surface

The last gene in Ebola is also common to viruses, and it's one that helps them latch on to and enter cells. It's called Glycoprotein, with the "glyco" referring to the fact that it's typically linked up to sugars on its way to the surface of the membrane.

The Ebola glycoprotein is hugely important. To begin with, as the only part of the virus that normally sticks out from the membrane, it's the primary thing that the immune system sees. If someone survives an infection and has antibodies to the virus, the chances are that these antibodies target the glycoprotein. As a result, efforts to develop a vaccine against Ebola—several of which are now fairly advanced—have focused on exposing the immune system to this glycoprotein, either by injecting the protein or by injecting a harmless virus that has been engineered to carry the gene that encodes it.

Antibodies that target the glycoprotein would have two effects. The first is that they would create antibody-virus aggregates that the immune system could safely clear. In addition, antibodies that bind to the glycoprotein can physically block it from latching on to cells, thus limiting the chances of further infections. The experimental treatments for Ebola that have been used recently are all based on the same principle, in that they consist of a collection of antibodies that target the glycoprotein.

There's also evidence that the glycoprotein is what actually kills individual cells. Inserting the gene alone into cells that normally line blood vessels is enough to cause their deaths. Glycoprotein appears to kill cells by blocking their ability to put new proteins on their surface. This causes the cells to lose contact with their neighbors and die. (It also has the side effect of limiting cells' ability to inform the immune system that they are infected.)

Further studies suggest that this effect is level-dependent; moderate amounts of glycoprotein don't cause cells much difficulty. It's only the high levels that accumulate later in infections that can kill them. This ensures that high levels of virus are made before their host dies.