Don't worry, it can't hurt you—yet.

Scientists have identified Reston ebolavirus—a member of the deadly Ebola group of hemorrhagic viruses—in domestic swine from the Philippines.

The virus, which looks like a piece of yarn with a slight bend, is the only Ebola pathogen not known to cause disease in humans. Even so, the U.S. Centers for Disease Control and Prevention in Atlanta considers it a biosafety level 4 pathogen, reserved for the most dangerous and exotic diseases.

Ebola and the closely related Marburg viruses are highly contagious, causing vomiting, diarrhea and bleeding with death rates as high as 90 percent. These viruses, originally from Africa, are thought to be caught from close contact with monkeys and apes, their primary hosts, although they have also been isolated from bats that show no symptoms.

Indeed, Reston ebolavirus was first identified in 1989 in crab-eating macaque monkeys that were shipped from the Philippines for research in Reston, Va. Human caretakers developed an immune response to the virus, but they never came down with any symptoms.

The latest outbreak of the Ebola family was discovered in July 2008 as the Philippine Department of Agriculture was investigating "blue ear disease" in pigs, a respiratory condition that causes their ears to turn blue from lack of oxygen. Investigators sent tissue and blood samples to Michael McIntosh at the U.S. Department of Agriculture's Foreign Animal Disease Diagnostic Laboratory at the Plum Island Animal Disease Center in Greenport, N.Y.

McIntosh says he was surprised to find that the tissue samples also contained the Reston strain, which had not been previously identified in swine. His team also confirmed pig-to-human Ebola transmission by identifying six pig handlers, whose blood tested positive for antibodies to the virus, although they showed no symptoms. Manila had announced preliminary findings in January, and McIntosh's study is published in this week's Science.

McIntosh says there are still a lot of unknowns, including how the virus was transmitted to the pigs and whether they show any symptoms independent of blue ear disease.  He worries that the virus's passage through pigs could allow it to mutate into something more harmful.  The research also raises the possibility that pigs could be infected with lethal Ebola strains. "What is the level of risk? We really don't know," he says, "The fact that it shows up in domestic pigs raises that risk."

9 Comments

1. 1. P.H. 03:08 PM 7/9/09

   Since humans appear to be asymptomatic after exposure, might this strain offer some benefit to vaccine research?

   Reply | Report Abuse | Link to this

2. 2. galaxy_man 09:18 AM 7/10/09

   It's dissimilar in configuration with its sister strains, Zaire, Sudan, and Marburg. I doubt it would actually help in the effort to produce any life-saving measures against those diseases. Also, there's always a possibility of mutation into a form that would create symptoms in humans.

   Reply | Report Abuse | Link to this

3. 3. leolima75 03:21 PM 7/10/09

   I think unless this new strain evolves into a form os the desease with a significant incubation period chances are samll that it'll ever become a pandemics... ebola kils much to fast and is thus easily contained currently.

   Reply | Report Abuse | Link to this

4. 4. Joy 05:36 AM 7/12/09

   Since when people are threatened by so many dreadful viruses that cause fatal disease. It makes me feel that we are exposed in a world of unsafety.

   Reply | Report Abuse | Link to this

5. 5. CB_Brooklyn 05:15 PM 7/12/09

   Press Release - Researchers Question Nature, Cause and Treatment of “Swine Flu” Outbreak
   http://www.checktheevidence.co.uk/cms/index.php?option=com_content&task=view&id=231&Itemid=75
   
   The Swine Flu Propaganda Explained
   http://www.checktheevidence.co.uk/cms/index.php?option=com_content&task=view&id=230&Itemid=75
   

   Reply | Report Abuse | Link to this

6. 6. Amandine in reply to CB_Brooklyn 09:48 AM 7/13/09

   "The Swine Flu Propaganda Explained"'s reference, http://www.whale.to/vaccine/sf1.html , stated that "...doctors had tried to suppress the symptoms of the typhoid with a stronger vaccine...", which is a really silly thing to say because vaccines do not treat diseases, they only prevent them. If the patient's immune system is already compromised, then a vaccine will be pointless, and even harmful.
   I do not believe this is a reliable source because of the time period of which it was written (1976), the emotional rhetoric and the covert angry tone.
   
   This mini documentary in PBS seems to explain the 1918 pandemic better.
   http://www.pbs.org/wgbh/nova/sciencenow/3318/02.html

   Reply | Report Abuse | Link to this

7. 7. vickiemc 10:12 AM 7/13/09

   "vaccines do not treat diseases, they only prevent them. If the patient's immune system is already compromised, then a vaccine will be pointless, and even harmful"
   
   Vaccines can either be prophylactic or therapeutic. Vaccines work by enhancing an immune response to a specific 'threat'. Prophylactic vaccines prep the body's immune system prior to invasion so that when infcetion occurs, it is primed to destroy the pathogen. Therapeutic vaccines (eg the therapeutic cancer vaccines in development) enhance the immune response in a person already suffering from the disease - it would be almost impossible (probably) to immunize every person in the coutry against every different type of cancer, but when a person does develop a certain cancer, the hope is that at that point, they could receive a vaccine against the particular type of cancer (including the specific markers that that cancer expresses), thereby re-directing the immune system towards the tumor.

   Reply | Report Abuse | Link to this

8. 8. crazy-dayz 11:17 PM 7/13/09

   Well, it's just like swine flu, isn't it? Originally, it wasn't contagious to humans, and now look. With Swine Ebola, if it isn't studied, it will probably mutate and transmit to humans. Then... well, you can imagine.

   Reply | Report Abuse | Link to this

9. 9. andi123456 05:14 AM 7/14/09

   It makes me feel that we are exposed in a world of unsafety.
   
   thanks for sharing....
   
   ___________________
   Andrew
   <a href="http://www.directstartv.com/jump.html?referID=oa-0-173189">Entertainment at one stop</a>
   

   Reply | Report Abuse | Link to this