First Swine Flu, Now Swine Ebola

Scientific American has an article on the latest virus found to be harbored by pigs: Ebola. (Reston ebolavirus). The virus was discovered in the Philippines being harbored by domestic pigs. The U.S. Centers for Disease Control and Prevention categorizes Ebola as a bio safety level 4 pathogen. This is the level reserved for the most dangerous viruses. This includes the variety found in the domestic Philippine pigs, despite the fact that the virus has never been found to cause symptoms in humans.

The swine variety of Ebola was found when the Philippine Department of Agriculture investigated a disease in the pigs known as “blue ear disease.” The disease is a respiratory illness that causes the pig's ears to turn blue from a lack of oxygen. Tissue samples were sent to U.S. Department of Agriculture's Foreign Animal Disease Diagnostic Laboratory, where the tissue samples were found to contain the Ebola virus.

More importantly (for humans, anyway) pig-to-human transition of the swine variety of the Ebola virus has been confirmed. Six pig handlers have tested positive to having antibodies to the virus in their blood, but have shown no symptoms. Interestingly, the Reston ebolavirus was first discovered in macaque monkeys shipped from the Philippines to Reston, VA for research. (This, presumably is where the name is derived from.) Again, handlers developed an immune response to the virus but never developed sysmptoms.

Currently, the Ebola variety infecting Philippine pigs seems to be far less dangerous than other varieties and the closely related Marburg viruses. It isn't even certain at this point whether the virus even causes symptoms in the host animals.

There is a risk that the virus could mutate into something more dangerous, and the fact that it can be transmitted to humans from the pigs is a reason for concern. Another reason for concern is the fact that pigs can harbor the Ebola virus. It is possible that pigs could catch a different form of the virus, one that is far more dangerous, and transmit that variety to humans.