First Aid and Treatment
Although B virus infection in humans is extremely rare, when it does occur, it is often fatal unless treated right away—about 70% of untreated patients die of complications associated with the infection.
Diligence in the recognition of possible exposures, followed by recommended first aid and rapid diagnosis of B virus infection, are the keys to controlling human B virus infection.
First aid should begin immediately:
- Cleanse the exposed area by thoroughly washing and scrubbing the area or wound with soap, concentrated solution of detergent, povidone-iodine, or chlorhexidine and water, and then
- Irrigate the washed area with running water for 15-20 minutes.
WARNING: a specimen for PCR testing should not be obtained from the wound area prior to washing the site because it could force virus more deeply into the wound, reducing the effectiveness of the cleansing protocol.
After the site is cleansed, a serum specimen should be obtained from the patient to provide a baseline antibody level. See Specimen Collection and B virus Detection.
The decision about whether to implement antiviral therapy or not should take into account the following criteria [adapted from the Recommendations for Prevention of and Therapy for Exposure to B virus (Cercopithecine Herpesvirus 1) , published in Clinical Infectious Diseases in 2002]:
- Type and physical condition of the implicated animal. Only monkeys of the macaque family serve as the natural reservoir for B virus infection. No other primates carry any risk of B virus transmission unless they have had the opportunity to become infected by a macaque. Infected macaques will not ordinarily be shedding B virus. Animals with lesions consistent with B virus infection (fluid-filled blisters on the skin) and animals that are immunocompromised or stressed are far likelier to be excreting virus.
- Thoroughness and timeliness of wound cleansing procedure. Wounds that have been cleansed within 5 minutes of exposure and that have been cleansed for at least 15 full minutes are less likely to lead to B virus infection. Delay in cleansing or inadequate cleansing of the wound increases the risk of infection.
- Nature of the wound. Bites or scratches that penetrate the skin, and particularly deep puncture wounds, are considered higher risk than wounds that are superficial and thus more easily cleansed. Wounds to the head, neck, or torso provide potentially rapid access to the CNS and thus should be considered higher risk. Prophylaxis is recommended for this type of wound regardless of its severity. Superficial wounds to the extremities are less likely to lead to fatal disease, and antiviral treatment is considered less urgent in such exposures.
- Exposure to materials that have come into contact with macaques. Accidental needlesticks with syringes that have come into contact with the CNS, eyelids, or mucosa of macaques are considered to carry a high risk of infection. Punctures from needles exposed to the peripheral blood of macaques are considered relatively low risk. Scratches resulting from contact with possibly contaminated objects, such as animal cages, are considered to carry a lower risk for infection.
It should be stressed, however, that in none of these potential exposures, can the risk of infection be considered zero. As such, the decision to treat with antivirals should be made at the physician’s discretion, with liberal consideration of the patient’s wishes and concerns.
People with a known risk of exposure should be monitored for symptoms regardless of whether a treatment regimen has or has not been implemented. The animal responsible for the putative exposure should be examined for evidence of disease, and serologic and PCR testing should be done to look for evidence of B virus infection and shedding.
Specific exposure scenarios and the corresponding urgency for post-exposure antiviral treatment, as proposed in the Recommendations for Prevention of and Therapy for Exposure to B virus (Cercopithecine Herpesvirus 1), are as follows:
Treatment is recommended
- Skin exposure (with loss of skin integrity) or mucosal exposure (with or without injury) to a high-risk source (e.g., a macaque that is ill, immunocompromised, known to be shedding virus, or has lesions compatible with B virus infection).
- Inadequately cleansed skin exposure (with loss of skin integrity) or mucosal exposure with or without injury
- Laceration of the head, neck, or torso.
- Deep puncture bite.
- Needlestick associated with tissue or fluid from the nervous system, lesions suspicious for B virus, eyelids, or mucosa.
- Puncture or laceration after exposure to objects (a) contaminated either with fluid from monkey oral or genital lesions or with nervous system tissues or (b) known to contain B virus.
- Post-cleansing culture is positive for B virus.
Treatment should be considered
- Mucosal splash that has been inadequately cleaned.
- Laceration (loss of skin integrity) that has been adequately cleaned.
- Needlestick involving blood from an ill or immunocompromised macaque.
- Puncture or laceration occurring after exposure to (a) objects contaminated with body fluid (other than that from a lesion) or (b) a possibly infected cell culture.
Treatment is not recommended
- Skin exposure in which the skin remains intact.
- Exposure associated with non-macaque species of non-human primates, unless they were in a situation where they could have been infected by a macaque.
Recommended dosages for specific antivirals are as follows.
Prophylaxis for exposure to B virus
- Valacylovir—1g by mouth every 8 hours for 14 days, or
- Acyclovir—800 mg by mouth 5 times daily for 14 days
Treatment of B virus infection
- With no CNS symptoms
- Acyclovir—12.5–15 mg/kg intravenously every 8 hours, or
- Ganciclovir—5 mg/kg intravenously every 12 hours
- With CNS symptoms
- Ganciclovir—5 mg/kg intravenously every 12 hours
It should be noted that while herpesvirus antivirals have been shown to effectively protect rabbits from lethal infectious doses of B virus, no comparable studies of efficacy in humans have been possible.
On external surfaces, B virus is susceptible to 1% sodium hypochlorite, 70% ethanol, 2% glutaraldehyde, and formaldehyde. The virus can also be inactivated by heat treatment at 50°–60°C for at least 30 minutes, by lipid solvents, by exposure to acidic pH, and by detergents.
B virus can remain viable in monkey CNS tissue and saliva and in monkey kidney cell cultures. The virus can also survive up to 7 days at 37°C or for weeks at 4°C, and it is stable at −70°C. Although survival studies under conditions of virus desiccation (i.e., dry surfaces) have not been performed, it is presumed that survival times will be comparable to those of other mammalian herpesviruses (with typical survival times of 3–6 hours).
There are no vaccines available for B virus. Experimental vaccines have been evaluated in animal models, but none are being considered for human trial.
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