By Chris Healey
Almost 25 years before the 2014 Ebola epidemic began spreading through West Africa – and the resulting treatment of two American Ebola patients on U.S. soil – public health officials responded to an Ebola outbreak inside the U.S.
Reston Ebola is the name given to an Ebola species discovered among macaque monkeys in a pharmaceutical research company’s primate quarantine unit in Reston, VA.
In 1989, a veterinarian at Hazelton Research Products, a pharmaceutical research company, contacted the United States Army Institute of Infectious Diseases at Fort Detrick, MD, concerning an unusually high mortality rate among macaques in a shipment from the Philippines. The veterinarian wanted USAMRIID to confirm suspected simian hemorrhagic fever, a viral illness lethal to primates but innocuous to humans. Tests on macaque carcasses unexpectedly showed signs of a deadly filovirus infection – Ebola hemorrhagic fever virus.
Initially, Ebola species Zaire – with mortality rates as high as 90%, and the cause of the 2014 African Ebola epidemic – was implicated as the agent at work. Faced with an unprecedented public health threat, state and federal health agencies converged on the primate quarantine facility in Reston. The Centers for Disease Control and Prevention monitored quarantine facility employees for Ebola symptoms. USAMRIID euthanized primates and sterilized the quarantine facility.
Comprehensive tests later identified the Zaire species identification as an error – Reston Ebola was a new species incapable of infecting humans. However, the enormous public health response was not unwarranted.
Unlike other Ebola species, researchers suspected Reston Ebola demonstrated airborne transmission at the quarantine facility. The longer the virus remained in human presence, the longer it was given opportunities to adapt. If Reston Ebola were to adapt to humans with airborne communicability it would pose a catastrophic public health risk.
Although no quarantine facility employees demonstrated Ebola-like symptoms during the 1989 outbreak, six workers produced Reston Ebola antibodies, meaning the virus elicited an immune response. Reston Ebola’s quick eradication was paramount to ensure that the virus—with its suspected airborne communicability—did not adapt to humans.
Restriction of the 2014 African Ebola epidemic to only a few countries has been attributed to the limited means of Ebola virus transmission. All Ebola species which affect humans are communicable only through direct contact with an infected person or their bodily fluids. Airborne transmission would increase viral spread and undermine containment efforts.