Information on the following diseases can be found in the Related Disorders section of this report:

• Acute Disseminated Encephalomyelitis

Simian B Virus Infection is characterized by fever, headache, vomiting, discomfort (malaise), and a stiff neck and back. These symptoms may be associated with neuromuscular dysfunction, respiratory difficulties, vision problems, cranial nerve abnormalities, alteration of consciousness, personality changes, seizures and/or partial paralysis (paresis). Some patients may go into a coma.

Simian B Virus Infection is caused by herpesvirus simiae (also known as B virus), a type of herpesvirus that is highly prevalent (i.e., enzootic) among macaque monkeys, i.e., certain Asiatic monkeys belonging to the "Macaca" genus. According to some reports, up to 80 or 90 percent of adult macaques may be infected with the virus.

In humans, Simian B Virus Infection may result from exposure to contaminated saliva from infected monkeys (e.g., from bites or scratches) or to simian tissue cultures of the virus, usually in laboratory settings. In addition, there has been at least one instance in which person-to-person transmission occurred.

According to reports in the medical literature, symptoms associated with Simian B Virus Infection typically occur within approximately two to five weeks after initial exposure.

Simian B Virus Infection usually occurs in an occupational setting in which employees have been bitten or scratched by infected monkeys or exposed to virus-infected simian tissue cultures. The disease was originally reported in a monkey handler in 1932. Through 1973, approximately 17 additional cases were reported in the medical literature. In addition, in 1987, four more individuals were affected by the disease, including the first documented case in which human-to-human disease transmission occurred. Fewer than a total of 40 cases of Simian B Virus Infection have been reported in humans to date. Researchers suggest, however, that the true frequency of Simian B Virus Infection may be difficult to assess, since it is possible that exposure to the virus may result in mild or no apparent symptoms (asymptomatic infection) in some cases.

Since 1975, United States public health regulations have prohibited the importation of primates as pets. However, according to researchers at the Centers for Disease Control and Prevention (CDC), there have been a number of incidents in nonoccupational settings in which individuals were exposed to the saliva of pet macaques (e.g., due to bites or scratches). According to one published CDC report, investigators examined seven nonoccupational exposures involving 24 individuals and eight monkeys. One exposed family had flu-like symptoms and another individual developed symptoms at the wound site suggesting infection. The researchers stress that infection must be assumed as a potential risk of macaque bite or scratch wounds, making macaques unacceptable as pets.

Symptoms of the following disorders can be similar to those of Simian B Virus. Comparisons may be useful for a differential diagnosis:

Acute Disseminated Encephalomyelitis is an infection of the nervous system characterized by headache, irritability, vomiting, drowsiness, light- sensitivity, difficulty in swallowing, lockjaw, incontinence, and diminished or exaggerated skin sensations. This disorder can be caused by viral infections acquired from sources other than Simian B Virus infected monkeys. It may be an allergic or toxic response of the nervous system to invading organisms such as bacteria or viruses. Neurological damage and intellectual impairment can follow an attack of this condition. (For more information on this disorder, choose "Encephalomyelitis" as your search term in the Rare Disease Database.)

The Centers for Disease Control and Prevention (CDC) has published a series of guidelines for the prevention of Simian B Virus Infection among monkey handlers. Such guidelines include receiving training in appropriate methods of restraint and the use of proper protective clothing and equipment when handling potentially infected monkeys. The CDC and the National Institutes of Health (NIH) have also published guidelines concerning appropriate measures for working with the B virus in a laboratory setting. For further information, please contact the CDC and/or the NIH (listed in the "References" section of this report below).

According to reports in the literature, in some affected individuals, the antiviral drug acyclovir may be effective in treating Simian B Virus Infection. In some cases, therapy may include intravenous infusion of ganciclovir, an antiviral medication structurally related to acyclovir.

Other treatment for Simian B Virus Infection is symptomatic and supportive.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com

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