A new host for Ebola

Contributed by Guest Blogger: S. Brucker ’14

Ebolavirus is a relatively new threat to the living world and therefore still enigmatic to the medical community in many ways. The question of where Ebolavirus strains come from remains unsettled, but they are thought to mainly infect humans and non-human primates. However, the feasible targets for Ebola expanded when researchers ran tests on pigs in the Philippines. A recent porcine epidemic in the Philippines lead the worried government to contact the USDA along with other mammalian medical laboratories for help diagnosing the problem. The disease was originally thought to solely be Porcine Respiratory and Reproductive Syndrome Virus (PRRSV) also known as “Blue Ear Disease,” but as it turns out, the swine were carrying something else. A technique called microarray analysis was used to identify any other pathogens infecting the pigs. This process consists of comparing an unknown genetic sample to an array of signature sequences belonging to known pathogens. The results of this test showed 28 out of 28 positive matches of the pigs’ genetic samples to signature Reston Ebolavirus (REBOV) sequences. This finding came as a surprise to a scientific community who believed Ebola to only infect primates. This seemingly small discovery has large implications for the way we think abut Ebola. Although Reston Ebolavirus has not yet been shown to infect humans, it is of concern that Ebola strains are appearing in the human food chain. This discovery leads to many questions that must be answered. How long has Ebola been able to infect pigs? If it recently evolved to include pigs in its host tropism, then what is different about this strain? What else can it affect? Are more virulent strains also going to evolve to expand host range? The biggest danger about Ebola is the fact that there is so much that we do not know about it, and until we answer these questions, the virus will be a constant threat.