What are the medical recommendations for someone exposed to macaques, potentially at risk for herpes B virus infection?

Management of Macaque Exposure

Anyone exposed to macaques through bites, scratches, or contact with bodily fluids requires immediate prophylaxis against herpes B virus (Cercopithecine herpesvirus 1), as this exposure can result in fatal meningoencephalitis with a 70% mortality rate if untreated. 1, 2

Immediate Wound Care

• Wash wounds and skin thoroughly with soap and water immediately after exposure. 1
• Irrigate the wound with sodium hypochlorite (dilute bleach) solution to reduce viral load at the exposure site. 2
• Flush mucous membranes with copious amounts of water if exposed to macaque saliva or other bodily fluids. 1

Risk Assessment for Herpes B Virus

All macaque species carry herpes B virus at extremely high rates:

• Long-tailed macaques (Macaca fascicularis) show seropositivity ranging from 25-100% across populations. 3
• Bonnet macaques carry the virus 73-100% of the time. 2
• 82% (31 of 38) of macaques at tourist sites in Bali tested positive for herpes B antibodies. 4

High-risk exposures requiring prophylaxis include: 1, 5

• Any bite that breaks the skin
• Scratches that penetrate the epidermis
• Contact of macaque saliva, mucous membranes, or neural tissue with open wounds or mucous membranes
• Exposure to macaque bodily fluids through broken skin

Antiviral Prophylaxis Protocol

Initiate antiviral therapy immediately—do not wait for symptom development, as herpes B encephalitis progresses rapidly and is often fatal once symptoms appear. 5, 6

Recommended Antiviral Agents:

• Acyclovir is the most commonly prescribed prophylactic agent for herpes B exposure. 5, 2
• Ganciclovir (intravenous) has been used successfully in treating symptomatic herpes B infection and may be considered for high-risk exposures. 6
• Valacyclovir is an acceptable alternative with better oral bioavailability than acyclovir. 5

Treatment Duration:

• Continue antiviral prophylaxis for at least 14 days post-exposure. 5
• Extend treatment if any neurological symptoms develop during the prophylactic period. 6

Rabies Prophylaxis

Administer rabies post-exposure prophylaxis (PEP) for all macaque bites or scratches, as nonhuman primates are considered high-risk rabies reservoir species. 1

• Give rabies immunoglobulin (RIG) at the exposure site. 5
• Initiate the rabies vaccine series immediately. 5
• Complete the full vaccine series even if the macaque's rabies status is later confirmed negative. 1

Clinical Monitoring and Follow-Up

Monitor closely for early signs of herpes B infection, which can present with subtle symptoms initially: 6

• Headache (often the earliest symptom)
• Fever
• Meningismus (neck stiffness)
• Altered mental status
• Focal neurological deficits
• Brain stem dysfunction signs (cranial nerve palsies, respiratory changes)

Seek immediate emergency care if any neurological symptoms develop, as progression to fulminant encephalomyelitis can occur within days. 6

Diagnostic Testing:

• Obtain baseline serology for herpes B virus if available. 6
• Consider MRI imaging if any neurological symptoms develop, as it can detect early brain stem involvement. 6
• Viral culture and PCR testing of lesions (if present) can confirm active infection. 6

Critical Pitfalls to Avoid

Never delay antiviral prophylaxis while awaiting test results or attempting to determine the macaque's infection status—assume all macaques are herpes B positive. 4, 3

Do not rely on the absence of visible lesions in the macaque, as infected monkeys are typically asymptomatic or have only mild oral lesions. 1

Simple wound management alone is insufficient and potentially fatal—consultation with infectious disease specialists, CDC, or local zoo veterinarians is essential for proper management. 2

Recognize that patient outcomes correlate directly with timing of antiviral initiation: 6

• Early treatment (before advanced symptoms) results in survival without sequelae
• Delayed treatment after respiratory arrest or brain stem dysfunction is often fatal despite aggressive therapy

Special Populations at Higher Risk

Workers at tourist sites, temples, or facilities with macaque contact face ongoing exposure risk: 4

• Nearly 50% of workers at macaque tourist sites report previous bites or scratches
• Risk is higher among those who feed macaques regularly
• Implement strict barrier precautions and avoid direct contact when possible