The plight of two U.S. aid workers who had been caring for victims of the deadly Ebola virus in West Africa and contracted the illness themselves has raised concerns about other microscopic killers that could lead to a pandemic.

“Ebola is only spread by direct contact with blood or bodily fluids,” says Infectious disease expert Dr. Catherine Troisi at the UT School of Public Health.  “What we should be worrying about is an airborne infection, which Ebola is not.  Even if we were to have a case here in the United States of someone who hops a plane in Africa and flies here and has been incubating Ebola, the likelihood of it spreading is virtually nil.”

The airborne virus that we don’t take seriously that Dr. Troisi warns of is influenza.  Flu.  It happens every year. 

“Thousands of people, tens of thousands of people, die every year from the flu,” Dr. Troisi tells KTRH News.

She says we got lucky with H1N1 in that not too many people died, but says the fear is that we will see a new virus that we won’t be so lucky with.  H7N9 is a mutated version of avian flu that infectious disease experts are watching closely.

“Right now, it doesn’t spread easily from person to person, but the virus can change easily, and if it acquires that characteristic we could have a pandemic,” Dr. Troisi cautions.

Middle East Respiratory Syndrome (MERS) has been spreading throughout the Arabian Peninsula, and there were two instances this year of Saudi health care workers infected with the virus flying to the U.S. (Indiana and Florida) and requiring hospitalization.  In both cases, the infection did not spread to anyone else.  It appears to have originated in camels, and in some cases has made the jump from camels to humans.  Infectious disease experts are closing monitoring the virus should it jump to being spread by human to human contact.

Henipavirus, originating from bats, is another cause for concern.  In most cases they have spread only to horses, and in isolated cases in Australia from horses to people.  The three known species can always morph into something new that can spread through a human population like wildfire.

The world came precipitously close to a pandemic in 2003 with SARS, Severe Acute Respiratory Syndrome. It spread to more than 20 counties with 8,098 people infected and 774 fatalities before the CDC and the WHO were able to eradicate it worldwide.