Reston virus

Reston virus (RESTV) is one of six known viruses within the genus Ebola virus in the family Filoviridae. Unlike its more famous relative, the Ebola virus, Reston virus is not known to cause disease in humans, although it can be lethal to nonhuman primates and pigs. First identified in 1989 in Reston, Virginia, USA, among imported crab-eating macaques, the virus has since been detected in the Philippines and China. The discovery of RESTV has heightened awareness of the potential for zoonotic transmission of filoviruses.

Discovery

The Reston virus was first identified in 1989 during an outbreak of a mysterious illness among crab-eating macaques (Macaca fascicularis) housed in a quarantine facility in Reston, Virginia. The facility was importing these monkeys for research and testing purposes. Initially, it was feared that the outbreak was caused by the much more deadly Ebola virus, but subsequent investigations identified the new virus, which was named after the location of its discovery.

Virology

Reston virus is an RNA virus with a filamentous structure, similar to other members of the Ebola virus genus. It is enveloped, with a genome consisting of a single strand of negative-sense RNA. The virus's replication mechanism involves entering a host cell, transcribing its RNA into positive-sense RNA, and then using this as a template to produce viral proteins and new viral RNA.

Pathogenesis and Symptoms

In nonhuman primates, Reston virus infection can lead to symptoms similar to those caused by the Ebola virus, including fever, respiratory distress, and, in severe cases, death. However, in humans, the virus appears to be asymptomatic or causes only mild flu-like symptoms. There have been several instances of laboratory workers in the United States and the Philippines testing positive for antibodies to RESTV, indicating they had been exposed to the virus, but none developed serious illness.

Transmission

The natural reservoir of Reston virus remains unknown, although bats are considered a likely candidate, as they are for other Ebola viruses. Transmission to primates and pigs in the Philippines and China has been associated with contact with contaminated materials or direct contact with infected animals. Human infections have been linked to exposure to infected nonhuman primates or pigs. There is no evidence of human-to-human transmission of Reston virus.

Prevention and Control

Given the lack of human disease associated with Reston virus, specific control measures have not been developed. However, general practices for controlling outbreaks of filoviruses include quarantine of infected individuals, use of personal protective equipment (PPE) by healthcare workers, and proper disinfection procedures. For Reston virus, monitoring and controlling infections in animal populations, particularly in settings where animals are imported or kept in close quarters, are key preventive measures.

Research and Implications

Research on Reston virus continues to provide valuable insights into the biology and epidemiology of filoviruses. Studies on the virus's transmission, pathogenesis, and potential for zoonotic spillover contribute to our understanding of how similar viruses can emerge and spread among human populations. The existence of Reston virus also underscores the importance of surveillance for emerging infectious diseases, particularly in regions with high biodiversity where humans frequently come into contact with wildlife.