Key points
- If your patient has been exposed to a macaque monkey, provide first aid and review the criteria for antiviral therapy.
- Monitor patients for symptoms, regardless of whether a treatment regimen has been implemented.
Who should receive treatment
Provide first aid if patient got exposed to a macaque monkey
Immediately wash and gently scrub the wound or area on the body that had contact with the monkey thoroughly with soap, detergent, or iodine for 15 minutes. Then, run water over the wound or area for 15 to 20 minutes more.
Criteria for antiviral therapy
When deciding whether to implement antiviral therapy, healthcare providers should consider the following:
1) Type and physical condition of the implicated animal
- More urgent: Only monkeys of the macaque family serve as the natural reservoir for B virus infection. However, infected macaques do not ordinarily shed B virus. Animals with wounds 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.
- Less urgent: No other primates carry any risk of B virus transmission unless they have become infected by a macaque.
2) Thoroughness and timeliness of wound cleansing procedure
- More urgent: Delay in cleansing or inadequate irrigating of the wound increases the risk of infection.
- Less urgent: Wounds that have been cleansed within 5 minutes of exposure and irrigated for at least 15 full minutes are less likely to lead to B virus infection.
3) Nature of the wound
- More urgent: Bites or scratches that break the skin, particularly deep puncture wounds, are considered higher risk than superficial ones. Wounds to the head, neck, or torso provide potentially rapid access to the central nervous system (CNS) and should be considered higher risk. Prophylaxis is recommended for this type of wound, regardless of its severity.
- Less urgent: Superficial wounds to the extremities are more easily cleansed and thus less likely to lead to fatal disease. Antiviral treatment is considered less urgent in these cases.
4) Exposure to materials that have come into contact with macaques
- More urgent: Accidental needle sticks with syringes that have come into contact with the CNS, eyelids, or mucosa of macaques are considered to carry a high risk of infection.
- Less urgent: Punctures from needles exposed to the blood of macaques are considered relatively low risk. Scratches resulting from contact with possibly contaminated objects, such as animal cages, are also considered to carry a low risk for infection.
Risk is never zero
In none of these potential exposures can the risk of infection be considered zero.
Decide whether to treat with antivirals with liberal consideration of the patient's wishes and concerns. Patients with a known risk of exposure should be monitored for symptoms, regardless of whether a treatment regimen has been implemented.
Prioritizing post-exposure antiviral treatment
B virus therapy recommendations
Refer to Clinical Infectious Diseases for more details about specific exposure scenarios and the corresponding urgency for post-exposure antiviral treatment.
- Skin or mucosal exposure, with or without injury, to a high-risk source.
- Examples: macaque that is ill, immunocompromised, known to be shedding virus, or has lesions compatible with B virus infection.
- Examples: macaque that is ill, immunocompromised, known to be shedding virus, or has lesions compatible with B virus infection.
- Inadequately cleansed skin exposure (where the skin is broken) or mucosal exposure (with or without injury).
- Laceration of the head, neck, or torso.
- Deep puncture bite.
- Needle stick associated with tissue or fluid from the nervous system, lesions suspicious for B virus, eyelids, or mucosa.
- Puncture or laceration with objects that are:
- Contaminated either with fluid from monkey oral or genital lesions or with nervous system tissues
- Known to contain B virus.
- Contaminated either with fluid from monkey oral or genital lesions or with nervous system tissues
- A culture taken after the wound was cleansed tests positive for B virus.
- A break in the skin that has been adequately cleaned.
- Needle stick involving blood from an ill or immunocompromised macaque.
- Puncture or laceration occurring after exposure to:
- Objects contaminated with body fluid (other than that from a lesion).
- A possibly infected cell culture.
- Objects contaminated with body fluid (other than that from a lesion).
- 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 antiviral dosages
Prophylaxes for exposure to B virus have been shown to effectively protect rabbits from lethal infectious doses of B virus. However, no comparable studies of efficacy in humans have been possible.
Valacylovir—1g by mouth every eight hours for 14 days, or
Acyclovir—800 mg by mouth five times daily for 14 days
With no CNS symptoms
Acyclovir—12.5–15 mg/kg intravenously every eight hours, or
Ganciclovir—5 mg/kg intravenously every 12 hours
With CNS symptoms
Ganciclovir—5 mg/kg intravenously every 12 hours