Source: European Commission DG ECHO via Flickr.

It's official: the first case of Ebola has been diagnosed on U.S. soil. According to the Centers for Disease Control and Prevention, a man in Dallas, who had been traveling from Liberia, was confirmed to have the Ebola virus as of Sept. 30.

As you might imagine, the diagnosis has unnerved Dallas residents and those who may have come in contact with this infected individual (some 80 people as of this writing). But even more so, it's frightened a nation that really has no concept of what the Ebola virus is, how it spreads, and what's being done to stop it from spreading beyond the current one confirmed case, considering that there is no approved cure for the deadly disease.

With that in mind, let's answer these questions so you can fully understand what this week's diagnosis actually means.

What is the Ebola virus and how does it spread?
The Ebola virus is a fairly rare and often fatal disease that presents with flu-like symptoms at first, but develops into more severe symptoms such as vomiting, diarrhea, and the perhaps the most distinct feature of the disease, unexplained hemorrhaging, which happens in a majority of cases. It's only during this latter stage that an infected individual is considered contagious.

Ebola virus budding from the surface of a Vero cell. Source: NIAID via Flickr.

The virus itself can lie dormant within the body for anywhere from two to 21 days, so infected individuals may not know if they've contracted it right away (one of the scarier aspects of the Ebola). However, it's important to note that Ebola can only be transmitted through an infected person's bodily fluids such as sweat or saliva. This isn't an airborne disease, nor is it something you can get through water, yet it's also not a disease to overlook as it can spread quickly in a hospital or healthcare setting if not quickly identified.

How deadly is the Ebola virus?
Although the current Ebola outbreak is the deadliest on record, it's also relatively small in scale when compared to other global killers. In total, some 6,500 people have been infected with the virus since it began to spread in Dec. 2013, and it's killed approximately 3,000 of those infected patients. By comparison, the World Health Organization notes that HIV/AIDS killed just shy of 1.1 million people in 2012. While mortality rates will vary depending on the source, Ebola tends to be lethal in 80%-90% of cases.

Source: European Commission DG ECHO via Flickr.

What's being done to stop Ebola from spreading?
At the moment, the CDC, as well as other health organizations around the world, are doing their best to quarantine infected patients and ensure that healthcare workers who come into contact with infected patients are wearing proper protective clothing, such as masks, gloves, gowns, and eye protection. Isolating Ebola patients should help reduce the spread of the disease as long as the aforementioned precautions are taken. 

In addition to carefully monitoring hospitals and advising U.S. citizens to avoid all non-essential travel to regions where the disease is most prevalent (Liberia, Sierra Leone, and Guinea), U.S. officials are also working with airports in these regions to ensure that passengers are screened for a fever before getting on their flights. Even though the Ebola virus can lie dormant for up to three weeks, it's a way of at least ensuring that no one flying is contagious during the flight.

Companies are also taking steps to reduce the potential for a pandemic. Integrated oil and gas giant ExxonMobil (NYSE:XOM), for instance, forbid its roughly 75,000 employees from traveling to the West African region for the time being.

Finally, U.S. officials have also urged biopharmaceutical companies to develop a vaccine to treat the Ebola virus.

Why Is an Ebola vaccine taking so long to produce?
It may not be the answer you want to hear, but the truth is that vaccine development takes a lot of time and costs a lot of money, and these two factors act to dissuade most drug developers from taking the plunge to develop a possible lifesaving cure.

Source: Flickr user Army Medicine.

As much as the public would like to see an Ebola vaccine hit pharmacy shelves, the Food and Drug Administration is also unwilling to sacrifice safety or efficacy in the process. Even with fast-track designations and priority reviews, drug companies will still need to dose patients and prove that their experimental Ebola vaccine is both safe and effective. It could be many months before Ebola clinical trials are complete and drug companies have enough data to submit their vaccine for approval. Once the application is filed with the FDA it could take a number of additional weeks or months to gain approval.

On top of the time it takes to develop a vaccine, or any drug for that matter, it's also very costly. A vast majority of lab-discovered drugs won't be approved by the FDA or will fail in clinical trials, so drug companies have to be picky about what they choose to develop. The costs to develop an Ebola vaccine might simply prove too high for most drug companies since the Ebola strain could mutate or the disease quickly vanish under quarantine controls, thus rendering an innovative vaccine useless and costing the developing company a fortune.

Which companies are currently working on an Ebola vaccine?
Currently, there are six major players that have taken on the task of trying to develop an Ebola vaccine.

Tekmira's experimental TKM-Ebola vaccine is probably the most-followed of the bunch given that, in August, the FDA removed its full clinical hold on TKM-Ebola and moved it instead to a partial clinical hold, thus allowing the vaccine the potential to be tested in human patients. TKM-Ebola has already been shown to be effective in preventing primates from what should have been lethal doses of the Ebola virus in preclinical studies. At the moment TKM-Ebola is in phase 1, or early stage studies, and is being developed in combination with the U.S. Department of Defense's Medical Countermeasure Systems BioDefense Therapeutics Join Product Management Office.

In addition to Tekmira, there are some large pharmaceutical companies throwing their clout around in an effort to cure this terrible disease. Johnson & Johnson, for example, received word a month ago from the FDA that it would fast-track the development of an investigational combo vaccine that would combine technology from J&J and partner Bavarian Nordic. With the assistance of the National Institutes of Health, or NIH, J&J hopes to begin clinical testing in early 2015.

Source: GlaxoSmithKline via Flickr.

Simialrly, GlaxoSmithKline and the NIH are cooperating to develop an Ebola vaccine with clinical research funding coming from an international consortium. GlaxoSmithKline began dosing its first patient early last month, and data from the study is expected before the year is over. Glaxo and J&J's experimental vaccines are particularly intriguing because both have the production capability to make tens of thousands of doses in short order if they needed to.

On the other hand, that's a problem for Sarepta Therapeutics' experimental Ebola vaccine candidate AVI-7537. Development on the vaccine began four years ago, but budgetary constraints sapped any follow-through on the project. At the moment Sarepta only has enough ingredients to make between 100-150 doses of AVI-7537.

Realistically, when might we see an approved vaccine?
Unfortunately, there's no set date as to when this might happen, but my best guess would be in the first half of 2015. GlaxoSmithKline's study, for instance, should have results before the year is over. In theory, it should be able to apply for an expedited approval shortly thereafter, upon which I'd have a hard time believing a regulatory agency wouldn't give it top priority. A number of other vaccines aren't scheduled to get results until well into the first quarter of 2015.

If and when we do have an approval from the FDA or another global agency, regardless of where that approval comes from, the big question is going to be whether or not the pharmaceutical company in question can keep up with vaccine demand. That's a question I, nor anyone, has the answer to as of yet. Right now the amount of vaccine needed wouldn't be astronomically high with less than 7,000 people in total getting infected with the virus, though a lot will depend on how well the virus is contained between now and when a vaccine is actually approved.