Macacine alphaherpesvirus 1

Macacine alphaherpesvirus 1 (formerly Macacine herpesvirus 1, Cercopithecine herpesvirus 1, CHV-1), Herpesvirus simiae, or Herpes virus B) is the Simplexvirus infecting macaque monkeys. Macacine alphaherpesvirus 1 is an alphaherpesvirus, which consists of a subset of herpes viruses that travel within hosts using the peripheral nerves. As such, this neurotropic virus is not found in the blood. Macacine alphaherpesvirus 1 (formerly Macacine herpesvirus 1, Cercopithecine herpesvirus 1, CHV-1), Herpesvirus simiae, or Herpes virus B) is the Simplexvirus infecting macaque monkeys. Macacine alphaherpesvirus 1 is an alphaherpesvirus, which consists of a subset of herpes viruses that travel within hosts using the peripheral nerves. As such, this neurotropic virus is not found in the blood. In the natural host, the virus exhibits pathogenesis similar to that of herpes simplex viruses (HSV) in humans. Conversely, when humans are zoonotically infected with Macacine alphaherpesvirus 1, patients can present with severe central nervous system disease, resulting in permanent neurological dysfunction or death. Severity of the disease increases for untreated patients, with a case fatality rate of approximately 80%. Early diagnosis and subsequent treatment are crucial to human survival of the infection. Linked with more than two dozen deaths since its discovery, Macacine alphaherpesvirus 1 is the only identified nonhuman primate herpesvirus that displays severe pathogenicity in humans. The last identified case of human Macacine alphaherpesvirus 1 infection occurred in 2008, with the last known fatality occurring in 1997 when researcher Elizabeth Griffin was splashed in the eye at Yerkes National Primate Research Center. Proper personal protective equipment is essential when working with macaques, especially those animals that have tested positive for the virus. Bites, scratches and exposures to mucous membranes, including the eye, must be cleaned immediately. Since the identification of the virus in 1932, there have been 31 documented cases of human Macacine alphaherpesvirus 1 infection, 21 of which led to death. At least 20 of the patients developed some degree of encephalitis. Macacine alphaherpesvirus 1 was first identified in 1932 following the death of William Brebner, a young physician who was bitten by a monkey while researching the virus that causes poliomyelitis. Soon after, Brebner developed localized erythema, followed by lymphangitis, lymphadenitis and, ultimately, transverse myelitis. Neurologic tissues obtained during Dr. Brebner’s autopsy revealed the presence of an ultrafilterable agent that appeared similar to HSV. This isolate was originally termed “W virus.” Within a year of Brebner’s death, Albert Sabin identified an unfilterable agent from the same tissue, which he later named B virus. Sabin further described the lethality of Macacine alphaherpesvirus 1 by showing that infectivity was independent of the route of inoculation. Additionally, it was observed that Macacine alphaherpesvirus 1 induced immunologic responses similar to HSV-1, as well as shared similarities to HVP-2 and Langur herpesvirus, two other nonhuman primate alphaherpesviruses. By 1959, Macacine alphaherpesvirus 1 was identified as the causative agent in 17 human cases, 12 of which resulted in death. Approximately 50 cases had been identified by 2002, although only 26 were well documented. The latest identified case of Macacine alphaherpesvirus 1 occurred in 2008, per the National B Virus Resource Center in Atlanta. Improvements in handling human cases have been made in the past several decades. Between 1987 and 2004 the rate of mortality has decreased, largely due to the addition of new forms of treatment and improved diagnosis. There have been a total of 5 fatalities related to Macacine alphaherpesvirus 1 in this timeframe. Traveling to an area where macaques are known carriers of the virus and interacting in close contact in areas such as temples poses a risk of exposure. However, even in endemic areas, human cases are rare. There have been no known cases of Macacine alphaherpesvirus 1 in travelers.