Updated

When it comes to fighting deadly diseases, the thin line between life and death often comes down to a question of time.

"The quicker you can detect it, the quicker you can get in there and do something about it," says Dr. Kristy Murray, a member of the Epidemic Intelligence Service team at the Centers for Disease Control and Prevention.

For 50 years now, when a disease has broken out anywhere in the world, the Atlanta-based EIS "Virus Hunters" have often been the first ones called. The elite team of disease detectives has been venturing out to the far corners of the globe to detect and fight infectious illness.

"We're saving lives every day; these investigators are out there to determine the health problem as quickly as possible, and put a stop to it," said CDC director Dr. Jeffrey Koplan, who was himself an EIS officer.

EIS officers are regarded as medical sleuths who work around the clock and serve as the first line of defense against unseen and often unknown killers. They've battled numerous diseases, including Hantavirus, malaria, E. coli, typhoid fever and the West Nile virus.

"Our officers are frequently in dangerous settings, because health disasters don't always occur in the most pristine and serene settings," Koplan told Fox News.

Throughout their 50-year history, EIS disease detectives have played a key role in the global eradication of smallpox. They were involved in restoring confidence in the polio vaccine, and now they are optimistic they can wipe the crippling virus off the face of the earth.

More recently, the EIS has received increased Congressional funding to help it fight against bioterrorism. Koplan says more resources have been needed to fight against the increased threat.

"We in the U.S., because of our position in the world, have to be prepared for this sort of thing," he said.

Murray, a bioterrorism specialist, agrees. "Certainly, in light of Iraq and the U.S. understanding that other countries have the ability to actually perform bioterrorism, we got concerned that there wasn't enough preparedness with these issues," she said.

Murray says keeping an eye on common symptoms among those who get sick is the key to early detection or bioterrorism, adding:

"Any time you have a cluster of of cases that are all very similar, and something above what you would normally see, that could certainly raise alarms for bioterrorism."

Some EIS investigations involve less-hazardous public-health matters, such as tracking strains of influenza or monitoring bike-helmet and seat-belt use.

But EIS officers who traveled to Uganda in the fight against the deadly Ebola virus have willingly placed themselves in harm's way.

"Every one of those investigators, on almost a daily basis, was in mortal danger," Koplan said. "I'm not exaggerating."