The outbreak of the deadly Ebola virus in West Africa is the largest oubreak ever recorded, has claimed the lives of 932 people as of the latest report from the WHO Wednesday, and has infected two American healthcare workers now receiving treatment in the U.S. Meanwhile, there is no vaccine, no FDA-approved treatment and no cure for the virus.

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Why is that? Les Funtleyder, portfolio manager at E Squared Asset Management who focuses on healthcare points to two factors. "It's so rare that it's hard to get a population large enough to do a trial," he says, and second, there's "really no commercial incentvie to do it. There's no money in emerging market diseases."

He explains that in a place like Africa, many people don't have health insurance. Without it, he says, there's no mechanism to pay for an expensive drug; therefore, pharmaceutical companies won't attempt to develop a drug that they won't get paid for.

The two American healthcare workers who were infected with the disease while treating patients in Africa and evacuated to the U.S. for treatment in Atlanta were reportedly given an experimental serum from privately-held biotech firm Mapp Pharmaceuticals. So, while there is no FDA-approved treatment, there are some companies purporting to have a treatment or be working on one, as in the case of a publicly-traded biotech company called Tekmira (TKMR).

Funtleyder is more skeptical. "Every time we see an outbreak [of a disease], we see an outbreak of companies who claim to have a drug or vaccine in an area," he says, noting that he wouldn't judge any experimental Ebola treatments until we see more than two patients treated with one.

Meanwile, shares in Tekmira were on a roller-coaster ride this week in reaction to various reports having to do with its in-the-works Ebola treatment. Shares were up 26% at one point Monday and then closed down 7%, and were rising again Tuesday, closing up 4%. Should investors stay away from trading any Ebola-related stocks?

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Funtleyder says yes, explaining that almost all of these outbreaks -- including MERS and SARS, and anthrax fears after 9/11 -- have led to ups and downs for shares in biotech companies that could play a role in treatments. Funtleyder says it usually doesn't end well. "It's hard to make a new drug for anybody, especially a small company. More drugs fail than succeed."

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