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Monkey, Macaque, and Baboon Bite or Scratch at Temples: Herpes B Virus (Macacine Alphaherpesvirus 1), Valacyclovir, and Rabies RIG

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Being bitten, scratched, or spat in the eye by a free-ranging monkey at a tourist temple, nature reserve, or urban park, most commonly an Old World Rhesus Macaque (Macaca mulatta), Long-Tailed / Crab-Eating Macaque (Macaca fascicularis), Japanese Macaque (Macaca fuscata), Barbary Macaque (Macaca sylvanus), or Baboon (Papio species) across Bali (Ubud), Thailand (Lopburi, Phuket), India (Varanasi, Jaipur, Shimla), Gibraltar, Japan (Arashiyama), Nepal, or Africa, is a dual neuro-virological emergency. In addition to carrying Rabies virus (100 percent fatal once neurological symptoms appear) and deep polymicrobial bite bacteria, 70 to 90 percent of adult Old World Macaque monkeys (genus Macaca) are lifelong asymptomatic carriers of Macacine alphaherpesvirus 1 (Herpes B Virus / Cercopithecine herpesvirus 1). While Herpes B causes nothing more than harmless oral cold sores in macaques, when inoculated into a human via a monkey bite, saliva-contaminated scratch, or ocular splash, untreated human Herpes B virus infection causes ascending encephalomyelitis and respiratory paralysis with a fatality rate exceeding 70 to 80 percent.

If you or a travel companion suffers any skin-breaking bite, scratch, or mucosal/eye splash from a macaque monkey or baboon, begin continuous 15-minute wound scrubbing with soap and povidone-iodine or chlorhexidine within the first 5 minutes, then go immediately to an international hospital or travel clinic for high-dose oral Valacyclovir (1 g PO three times daily for 14 days) and Rabies Post-Exposure Prophylaxis (Human Rabies Immune Globulin [HRIG] + 4-dose rabies vaccine). For local ambulance or medical assistance, call your local emergency number (112 or 119 in Indonesia, 1669 in Thailand, 112 in India and the European Union / Gibraltar, 119 in Japan, 999 in the United Kingdom, 911 in the United States and Canada) or check our global directory of emergency numbers. For broader animal bite and rabies protocols, see rabies exposure and post-exposure prophylaxis, animal bites and wound infection care, and severe bleeding control.

Do this now

  1. SCRUB THE WOUND VIGOROUSLY FOR A FULL 15 MINUTES IMMEDIATELY (THE SINGLE MOST IMPORTANT STEP): Do not wait until you reach a clinic to wash the wound. Herpes B virus and rabies virus are lipid-enveloped viruses that sit inside superficial skin cells during the first few minutes before entering peripheral nerve endings. Immediately flush and scrub the bite or scratch continuously for 15 full minutes by the clock using povidone-iodine (Betadine), chlorhexidine gluconate (Hibiclens), or concentrated detergent soap (dish soap / laundry bar) and running water.
  2. IF SPAT IN THE EYE OR MOUTH, IRRIGATE WITH PLAIN WATER OR SALINE FOR 15 MINUTES (NO SOAP IN EYES): If a macaque hisses, spits, or splashes water/saliva into your eye, nose, or mouth, flush the open eye or mucosa continuously for 15 minutes with clean bottled drinking water or sterile normal saline (never put harsh detergent, alcohol, or surgical scrub solution into the eye, which damages the cornea).
  3. NEVER LET A CLINIC SUTURE OR GLUE A MONKEY BITE CLOSED: Closing a primate bite with stitches or skin glue traps Herpes B virus, rabies virus, and oral anaerobes (Eikenella corrodens, Bacteroides, Pasteurella) against damaged nerve fibers and tendons. Leave the wound open to drain (or allow only loose approximation after infiltration with Rabies Immune Globulin).
  4. START ORAL VALACYCLOVIR (1 GRAM THREE TIMES DAILY) WITHIN 24 TO 72 HOURS FOR MACAQUE EXPOSURES: Only monkeys of the genus Macaca (Macaques across Asia and Gibraltar) carry Herpes B virus. Insist on starting Post-Exposure Prophylaxis (PEP) with oral Valacyclovir 1,000 mg (1 g) every 8 hours (TID) for 14 days (or oral Acyclovir 800 mg 5 times daily for 14 days) ideally within 24 hours (and up to 72 hours) of the exposure, before the virus crosses into the central nervous system.
  5. DEMAND BOTH RABIES IMMUNE GLOBULIN (HRIG / ERIG) AND RABIES VACCINE ON DAY 0: Every monkey or baboon bite or scratch that draws blood in Asia, Africa, or Latin America is a WHO Category III Rabies Exposure. If you have not had pre-exposure rabies vaccinations, a rabies vaccine alone is NOT enough, you must also receive Rabies Immune Globulin (HRIG 20 IU/kg or ERIG 40 IU/kg) infiltrated directly into and around the wound on Day 0 to neutralize virus during the 7 to 14 days before your body makes its own antibodies.
  6. RECEIVE AMOXICILLIN-CLAVULANATE (AUGMENTIN) AND A TETANUS BOOSTER: Primate mouths mimic human bite flora (the most infectious mammalian bite); take amoxicillin-clavulanate 875/125 mg PO BID for 5 to 7 days and verify your tetanus immunization (Tdap).

Danger

Why the First 5 to 15 Minutes of Scrubbing Decides Survival in Herpes B Virus Exposure: CDC and National B Virus Resource Center pathophysiological studies show that Macacine alphaherpesvirus 1 (Herpes B Virus) possesses a fragile outer lipid envelope. When a macaque bites or scratches human skin, viral particles from the monkey's saliva sit inside the epidermis and dermis for a brief window before binding to sensory nerve axons (retrograde axonal transport along peripheral nerves to the dorsal root ganglia and brainstem). Delaying wound washing by even 30 to 60 minutes until arriving at a hospital allows the virus to enter the nerve axon, where surface soap can no longer reach it. Immediate, aggressive 15-minute scrubbing with detergent soap, povidone-iodine, or chlorhexidine dissolves the viral lipid envelope on contact and reduces the infectious viral load by over 99 percent.

Decision tree: monkey, macaque, and baboon bite or scratch management

Follow this clinical and field decision tree the moment a primate encounter results in a bite, scratch, or mucosal splash:

flowchart TD
    Exposure["Primate Bite, Scratch, or Saliva Splash on Skin/Eye"] --> WashNow{"1. Immediate Decontamination (Within 0 to 5 Minutes)"}
    WashNow -->|"Skin Bite, Puncture, or Scratch"| Scrub15["SCRUB VIGOROUSLY FOR 15 FULL MINUTES: Use Povidone-Iodine, Chlorhexidine, or Detergent Soap + Running Water -> Let bleed freely -> Never suture shut"]
    WashNow -->|"Saliva Splash into Eye, Nose, or Mouth"| FlushEye["IRRIGATE EYE / MUCOSA FOR 15 MINUTES: Use Plain Bottled Water or Sterile 0.9% Saline ONLY (Never put soap or iodine in eyes)"]
    Scrub15 --> PrimateID{"2. Identify the Primate Group and Geography"}
    FlushEye --> PrimateID
    PrimateID -->|"Old World MACAQUE (Genus Macaca: Bali, Thailand, India, Japan, Gibraltar, China, Philippines)"| DualRisk["HIGH RISK FOR HERPES B VIRUS + RABIES + BACTERIA: Go to International Travel Clinic / Hospital Within 24 Hours"]
    PrimateID -->|"Non-Macaque Primate (Baboon, Vervet, Langur, Capuchin, Squirrel Monkey, Marmoset)"| RabiesOnly["NO HERPES B RISK -> HIGH RISK FOR RABIES + BACTERIA: Go to Hospital for Rabies PEP + Antibiotics"]
    DualRisk --> MedProtocol["3. Administer Complete Post-Exposure Medical Regimen (Day 0)"]
    RabiesOnly --> MedProtocol
    MedProtocol --> Regimen["1. HERPES B PEP (Macaques Only): Valacyclovir 1 g PO TID x 14 days (or Acyclovir 800 mg PO 5x/day x 14 days)\n2. RABIES PEP (WHO Cat III): Infiltrate HRIG (20 IU/kg) into wound + Rabies Vaccine Days 0, 3, 7, 14\n3. ANTIBIOTICS & TETANUS: Amoxicillin-Clavulanate 875/125 mg PO BID + Tdap Booster"]
    Regimen --> NeuroWatch{"4. Monitor for 21 Days: Any Vesicles, Tingling, Fever, Double Vision, or Hiccups?"}
    NeuroWatch -->|"YES: Early Neuro / Skin Signs"| IVGanciclovir["EMERGENCY HOSPITAL ADMISSION: Start High-Dose IV Acyclovir (12.5-15 mg/kg q8h) or IV Ganciclovir (5 mg/kg q12h) Immediately"]

Phase 1: Which primates carry Herpes B virus vs. Rabies (Species and temple guide)

Not every monkey on Earth carries Herpes B virus, and not every primate region has the same rabies endemicity. Knowing exactly which primate bit or scratched you determines your antiviral prescription.

1. Global Primate Pathogen Matrix: Macaques vs. Baboons, Langurs, and New World Monkeys

Primate Group & Common Species Famous Tourist & Encounter Locations Herpes B Virus (Macacine alphaherpesvirus 1) Risk? Rabies Virus Risk? Mandatory Post-Exposure Prophylaxis (PEP)
1. Old World Macaques (Genus Macaca: 23 species):
- Long-tailed Macaque (M. fascicularis)
- Rhesus Macaque (M. mulatta)
- Japanese Macaque (M. fuscata)
- Barbary Macaque (M. sylvanus)
- Bonnet / Toque / Pig-tailed Macaques
- Bali, Indonesia (Ubud Sacred Monkey Forest, Uluwatu Temple)
- Thailand (Lopburi, Phuket Monkey Hill, Krabi)
- India & Nepal (Varanasi, Jaipur, Agra, Swayambhunath)
- Malaysia & Singapore (Batu Caves, MacRitchie)
- Gibraltar (Upper Rock)
- Japan (Arashiyama, Jigokudani)
- Hong Kong (Kam Shan)
YES: HIGH (70% to 90% of adult macaques are seropositive carriers; shed virus intermittently in saliva, conjunctival fluid, and urogenital secretions, especially when stressed or breeding). YES across Asia, India, and North Africa. (Note: Japan, Singapore, and Hong Kong are officially terrestrial-rabies-free, though local clinical consultation is still required; Bali and mainland SE Asia/India have active rabies). 1. 15-min Povidone-Iodine / Soap Scrub
2. Oral Valacyclovir (1 g TID x 14d)
3. Rabies HRIG + 4-Dose Vaccine (in endemic zones)
4. Amoxicillin-Clavulanate + Tetanus
2. Baboons (Genus Papio), Vervet Monkeys (Chlorocebus), and Asian Langurs / Leaf Monkeys (Semnopithecus / Trachypithecus) - South Africa (Cape Peninsula), Kenya, Tanzania, Zimbabwe (Victoria Falls)
- India & Sri Lanka (Hanuman Langurs at temples)
- Saudi Arabia (Hamadryas baboons in Taif/Abha)
NO (Zero Herpes B transmission to humans): Baboons and vervets carry related simian herpesviruses (SA8, HVP2) that do not cause fatal human disease, though macaques and other primates housed together in cages can cross-infect. YES: HIGH: Baboons, vervets, and langurs in Africa, Arabia, and India can transmit rabies as well as severe crushing/avulsive bacterial wounds. 1. 15-min Soap/Iodine Scrub
2. Rabies HRIG + 4-Dose Vaccine
3. Amoxicillin-Clavulanate + Tetanus
(Valacyclovir NOT required unless species is uncertain and could be a macaque)
3. New World Monkeys (Central & South America):
- Capuchins (Cebus)
- Squirrel Monkeys (Saimiri)
- Howler / Spider Monkeys
- Marmosets (Callithrix)
- Costa Rica (Manuel Antonio)
- Brazil (Rio de Janeiro, Amazon)
- Peru, Colombia, Mexico
NO (Zero Herpes B): New World monkeys do not carry Herpes B virus. YES: VERY HIGH: Especially Marmosets (Saguis) in Brazil and capuchins, which maintain a distinct, highly lethal primate rabies variant (Antigenic Variant 3 / Marmoset variant). 1. 15-min Soap/Iodine Scrub
2. Immediate Rabies HRIG + 4-Dose Vaccine
3. Amoxicillin-Clavulanate + Tetanus

2. Why Temple Macaques Attack Tourists (And How to Escape Without Being Bitten)

Studies at Bali's Ubud Monkey Forest, Thailand's Lopburi temples, and Gibraltar's Upper Rock show that over 85 percent of macaque bites occur during three specific human behaviors: 1. Holding onto Food, Plastic Bags, Water Bottles, Sunglasses, or Phones: Temple macaques are trained by experience to snatch eyeglasses, hats, phones, and crinkly bags, holding them hostage until a handler trades them a piece of fruit (a learned bartering behavior). If a monkey grabs your bag, sunglasses, or water bottle, LET GO IMMEDIATELY. Pulling back triggers an instant deep canine bite to your hand or forearm. 2. Smiling With Exposed Teeth or Direct Staring (Primate Threat Display): In macaque and baboon body language, locking direct eye contact and pulling your lips back to show your teeth (a human smile for a selfie) is the universal primate gesture of fear-aggression and challenge. Keep your lips closed over your teeth, avoid direct staring, and never squat down at eye level with an adult male macaque or a mother carrying an infant. 3. Climbing Onto Tourists' Shoulders (Head and Neck Bite Hazard): Never allow a temple vendor to place peanuts or bananas on your head or shoulders so a macaque climbs onto your neck. Bites or scratches to the head, face, or neck carry the highest mortality risk for both Herpes B virus and Rabies because the cranial nerves (trigeminal, facial) provide an ultra-short pathway (just centimeters) straight into the brainstem before post-exposure prophylaxis can take effect.

Phase 2: Step-by-step first aid and medical prophylaxis (First 15 minutes to 72 hours)

When a macaque or baboon breaks the skin or splashes a mucous membrane, follow this exact chronological timeline.

1. Minute 0 to Minute 15: Mechanical and Chemical Viral Inactivation

   [ MINUTE 0: MACAQUE BITE, SCRATCH, OR SALIVA SPLASH ]
                            |
                            v
   +--------------------------------------------------------------------+
   |  DO NOT WAIT FOR A CLINIC START 15-MINUTE SCRUB IMMEDIATELY      |
   |  1. Skin Wound: Scrub for 15 FULL MINUTES with:                    |
   |     - Povidone-Iodine (Betadine), Chlorhexidine, OR                |
   |     - Concentrated Detergent / Dish Soap / Hand Soap + Water.      |
   |  2. Eye/Mouth Splash: Flush 15 FULL MINUTES with Plain Bottled     |
   |     Water or 0.9% Sterile Saline ONLY (No soap/iodine in eye).     |
   +--------------------------------------------------------------------+
                            |
                            v
   [ HOUR 1 TO HOUR 24: HOSPITAL POST-EXPOSURE PROPHYLAXIS (PEP) ]
     - Valacyclovir 1,000 mg (1 g) PO TID x 14 days (for Macaques)
     - Rabies HRIG (20 IU/kg) infiltrated into wound + Vaccine Day 0
     - Amoxicillin-Clavulanate 875/125 mg PO BID + Tetanus Booster
  • Why 15 Full Minutes Is Mandatory: Both the CDC Herpes B Virus Working Group (Cohen et al., Clinical Infectious Diseases) and the World Health Organization (WHO) Rabies Guidelines specify a full 15 minutes of continuous washing and mechanical scrubbing (use a clean gauze pad or soft cloth to gently scrub inside the tooth puncture or scratch track, allowing minor venous bleeding to flush out saliva).
  • What Virucidal Agents Work on Herpes B and Rabies?:
  • First Choice for Skin: Povidone-iodine (Betadine 7.5% to 10%), chlorhexidine gluconate (2% to 4%), benzalkonium chloride, or concentrated household detergent / liquid dish soap / bar soap with copious running water.
  • What If You Are on a Temple Trail With Only a Water Bottle and Hand Sanitizer?: Flush immediately with half of your bottled drinking water while rubbing the wound vigorously, apply 70% alcohol hand sanitizer, and rush within 3 to 5 minutes to the temple first-aid booth, restroom sink, or nearest pharmacy to buy povidone-iodine and soap for the full 15-minute scrub. (Note: At Ubud Sacred Monkey Forest in Bali and major Thai temples, an on-site first-aid clinic has povidone-iodine, go there immediately, wash for 15 minutes, and then go straight to an international hospital for Valacyclovir and Rabies RIG, as temple booths only put Betadine on the skin and do NOT dispense antivirals or rabies vaccines).

2. Hour 1 to Hour 72: Antiviral Prophylaxis for Herpes B Virus (Valacyclovir vs. Acyclovir)

According to the US Centers for Disease Control and Prevention (CDC) and the National B Virus Resource Center (Georgia State University) clinical guidelines:

Clinical Parameter First-Line Regimen (Preferred) Alternative Oral Regimen Important Clinical & Dosing Rules
Drug Name & Adult Oral Dose Valacyclovir (Valtrex):
1,000 mg (1 gram) orally three times daily (every 8 hours / TID) for 14 days (Total: 3 grams/day).
Acyclovir (Zovirax):
800 mg orally five times daily (every 4 hours while awake) for 14 days (Total: 4 grams/day).
Why Valacyclovir Is Preferred: Valacyclovir is the L-valyl ester prodrug of acyclovir and achieves 3 to 5 times higher serum bioavailability than oral acyclovir, which is critical because Herpes B virus is roughly 10-fold less susceptible (higher IC50) to acyclovir than human Herpes Simplex Virus (HSV-1/HSV-2). Never accept a low cold-sore dose (such as acyclovir 200 mg or 400 mg TID), you must take the full high-dose herpes zoster/Herpes B regimen (1 g Valacyclovir TID or 800 mg Acyclovir 5x/day).
Optimal Timing Window Start ideally within 24 hours (and up to 72 hours / 3 days) of the macaque bite or scratch. Same (within 24 to 72 hours). Even if more than 72 hours (up to 5 days) have elapsed since a high-risk macaque bite before you reach a major medical center, infectious disease specialists often still initiate a 14-day course of Valacyclovir while monitoring closely for neurological symptoms.
Which Macaque Exposures Require Valacyclovir PEP? 1. High Risk (Mandatory PEP):
- Any skin-breaking bite or deep scratch from a macaque (especially to the head, neck, torso, or hands).
- Macaque saliva or fluid splashed into the eye, nose, mouth, or an open cut.
- Bite/scratch from a macaque that looks sick, lethargic, or has oral ulcers.
2. Low Risk (PEP Generally Not Required):
- Macaque touches intact, unbroken skin.
- Bite or scratch from a non-macaque monkey (baboon, langur, vervet, capuchin, marmoset) with no macaque contact.
Renal Hydration Rule: High-dose Valacyclovir (3 g/day) and Acyclovir (4 g/day) are excreted by the kidneys and can precipitate acyclovir crystals in renal tubules if you are dehydrated in a hot tropical climate. Drink at least 2.5 to 3 liters of water daily while taking the 14-day course, and adjust the dose if you have chronic kidney disease (reduced eGFR).
Pediatric & Pregnancy Considerations Pregnancy: Valacyclovir (1 g TID) or Acyclovir (800 mg 5x/day) is strongly recommended during pregnancy after a macaque bite because maternal Herpes B encephalomyelitis has a >70\% fatality rate, and acyclovir/valacyclovir have an established pregnancy safety record. Children: Pediatric oral acyclovir (20 mg/kg/dose PO 4 to 5 times daily, max 800 mg/dose) or weight-adjusted valacyclovir for 14 days under pediatric infectious disease guidance. Do not stop the 14-day course early even if the skin scratch heals completely within 3 days; stopping early can allow suppressed viral replication to rebound (late-onset encephalomyelitis).

3. Simultaneous Rabies Post-Exposure Prophylaxis (HRIG + 4-Dose Vaccine Schedule)

While travelers in the United States or Europe often read papers debating whether wild vs. captive laboratory macaques need Herpes B vs. Rabies care, at Asian and African tourist temples, you must treat BOTH simultaneously. Do not let a local clinic give you only a rabies shot without Valacyclovir, and do not take only Valacyclovir without Rabies PEP:

  1. For Unvaccinated Travelers (No Prior Pre-Exposure Rabies Series):
  2. Step A: Passive Immunity (Day 0 Only): Infiltrate Human Rabies Immune Globulin (HRIG at 20 IU/kg body weight), or purified Equine Rabies Immune Globulin (ERIG at 40 IU/kg) if HRIG is unavailable, directly into the depth and edges of every bite and scratch mark. Any remaining volume that cannot anatomically fit into the wound(s) (for example, a bite on a finger tip) is injected intramuscularly at a distant site (such as the anterior thigh or deltoid opposite the vaccine arm).
  3. Critical 7-Day HRIG Window: If the remote clinic where you receive your Day 0 rabies vaccine is out of stock of HRIG (a common issue at small island clinics in Indonesia or rural India), you have up to Day 7 after the first vaccine dose to fly or travel to a major hospital (Denpasar, Bangkok, Singapore, New Delhi, or home) to get HRIG injected. Do not administer HRIG after Day 7, as it will suppress your own active vaccine antibody response.
  4. Step B: Active Immunization (4-Dose Intramuscular Vaccine Series): Inject 1.0 mL (or 0.5 mL depending on brand: Verorab, Rabipur/RabAvert, Imovax) intramuscularly into the deltoid muscle (never into the gluteal/buttock muscle, or anterolateral thigh in young children) on Days 0, 3, 7, and 14 (plus Day 28 if immunocompromised).
  5. For Previously Vaccinated Travelers (Completed Pre-Exposure PrEP or Prior PEP):
  6. Do NOT give HRIG. Administer 2 intramuscular booster doses of rabies vaccine on Day 0 and Day 3 only.

4. Polymicrobial Bacterial Prophylaxis (Why Monkey Bites Infect Within 12 Hours)

Non-human primate oral cavities contain high concentrations of alpha-hemolytic Streptococci, Staphylococcus aureus, Eikenella corrodens, Pasteurella, Bacteroides, and Fusobacterium: - First-Line Oral Antibiotic: Amoxicillin-clavulanate (Augmentin 875/125 mg PO every 12 hours for 5 to 7 days). - Penicillin-Allergic Patients: Doxycycline (100 mg PO BID) or Moxifloxacin (400 mg PO daily), or Ciprofloxacin (500 mg PO BID) PLUS Metronidazole (500 mg PO TID) or Clindamycin (300-450 mg PO TID) (never use a single cephalosporin, macrolide, or clindamycin alone, which miss Eikenella and Pasteurella).

Phase 3: Recognizing Herpes B virus symptoms (The 3-to-30-day neurological red-flag window)

Even after completing wound scrubbing and starting Valacyclovir, every person bitten or scratched by a macaque must monitor themselves daily for 30 days (most clinical Herpes B cases present within 3 to 21 days of exposure, though incubation up to 5 weeks can occur).

   STAGE 1: LOCAL & PERIPHERAL NERVE SIGNS (Days 2 to 10)
   - Fluid-filled blisters (vesicles) or ulceration at the bite/scratch site
   - Shooting pain, electric tingling (paresthesia), numbness, or intense itching
     radiating UP the bitten arm or leg toward the spine
   - Regional swollen lymph nodes, unexplained fever, myalgia, or severe headache
                            |
                            v
   STAGE 2: BRAINSTEM & SPINAL CORD INVASION (Ascending Encephalomyelitis)
   - Persistent intractable HICCUPS (classic sign of brainstem/phrenic nerve involvement)
   - Double vision (diplopia), drooping eyelid, dizziness (ataxia), or slurred speech
   - Neck stiffness (meningismus), confusion, urinary retention, or leg weakness
                            |
                            v
   --> IMMEDIATE ICU ADMISSION FOR INTRAVENOUS GANCICLOVIR OR HIGH-DOSE IV ACYCLOVIR
  • Why Persistent Hiccups, Diplopia, or Tingling Up the Limb Requires Immediate IV Antivirals:
  • Unlike human cold sores (HSV-1), Herpes B virus frequently travels up peripheral nerves without even forming a visible skin blister at the bite site (> 50% of patients never develop local vesicles).
  • Instead, the earliest warning sign is neuropathic pain, burning, numbness, or intense itching (pruritus) radiating proximally up the bitten extremity, followed by flu-like fever, persistent hiccups (singultus, caused by viral inflammation of the medulla oblongata), double vision (diplopia), difficulty swallowing (dysphagia), or ascending limb weakness (Landry-type ascending paralysis).
  • Hospital Inpatient Treatment for Symptomatic Herpes B: Oral Valacyclovir is strictly for prevention (PEP) before symptoms appear. Once any local blister or neurological symptom develops, the patient requires immediate emergency hospitalization and intravenous antiviral therapy:
    1. Without CNS Symptoms (Local skin vesicles or peripheral paresthesia only): Intravenous Acyclovir (12.5 to 15 mg/kg IV every 8 hours) OR Intravenous Ganciclovir (5 mg/kg IV every 12 hours) for at least 14 to 21 days until all symptoms resolve and viral PCR cultures are negative.
    2. With Any CNS / Brainstem Symptoms (Fever + headache, tingling, hiccups, diplopia, ataxia, or weakness): Intravenous Ganciclovir (5 mg/kg IV every 12 hours) is the drug of choice recommended by the CDC Herpes B Working Group because ganciclovir exhibits significantly greater in vitro and in vivo potency against Macacine alphaherpesvirus 1 inside the central nervous system than acyclovir.

Warning

Why You Must Never Swab or Culture the Wound Before Scrubbing It: In laboratory settings, technicians were historically taught to swab a wound for baseline viral PCR before washing. The CDC explicitly warns against swabbing a monkey bite before washing: taking even 2 minutes to locate a swab and sample the wound gives Herpes B virus time to enter sensory nerve endings, and swabbing physically pushes surface virus deeper into the dermis. Always scrub for 15 minutes first; if viral PCR or serology testing is needed later, it is performed after decontamination through the National B Virus Resource Center (+1-404-413-6550) or your national reference laboratory.

Tip

Traveler's Temple-Visit Prevention Kit: If your itinerary includes macaque temples or trails in Bali, Thailand, India, Gibraltar, or Japan, pack a 60-mL travel bottle of 10% Povidone-Iodine (Betadine) and a 500-mL bottle of plain drinking water in a zipped backpack (never carry loose plastic bags or visible food/bottles in your hands), wear long trousers and closed shoes, and consider completing the 2-dose Pre-Exposure Rabies Vaccine series (Days 0 and 7) before departure so you never have to hunt for scarce Human Rabies Immune Globulin (HRIG) in a foreign emergency room. Taking a Travel Medicine and Wilderness First Aid course from the Red Cross, St John Ambulance, or an ISTM clinic prepares you to act in the critical first 5 minutes.

Regional emergency numbers, international clinics, and reference laboratories

After completing your immediate 15-minute wound scrub on site, go directly to an international hospital or dedicated travel medicine clinic (do not rely solely on a temple first-aid booth or hotel nurse):

  • Bali & Indonesia: Dial 112 or 119 for ambulance. In Bali (Ubud / Kuta / Nusa Dua / Canggu), go directly to BIMC Hospital (Kuta: +62 361 761263 / Nusa Dua: +62 361 3000911 / Ubud Medical Centre: +62 361 971313), Siloam Hospital Denpasar (+62 361 779900), or SOS Medika Clinic Bali (+62 361 710505), which stock imported HRIG (Berirab/HyperRAB), Verorab vaccine, and oral Valacyclovir (Valtrex).
  • Thailand (Bangkok, Phuket, Lopburi, Krabi, Chiang Mai): Dial 1669 for EMS or 1155 for Tourist Police. Go to the Queen Saovabha Memorial Institute (Thai Red Cross Society Snake & Rabies Clinic, Bangkok: +66 2 252 0161), Bangkok Hospital Phuket (+66 76 254 425), or Bumrungrad International Hospital (+66 2 066 8888).
  • India & Nepal: Dial 112 (108 ambulance) in India; in Kathmandu (Swayambhunath Monkey Temple), go directly to CIWEC Hospital Travel Medicine Center (+977 1 4524111), the gold-standard primate bite clinic in the region. In India, go to a major tertiary corporate hospital (Apollo, Max, Fortis, Manipal) and request both Human Rabies Immune Globulin (HRIG) and Valacyclovir 1,000 mg tablets (Valcivir).
  • Gibraltar, United Kingdom, and European Union: Dial 112 or 190 in Gibraltar (St Bernard's Hospital has a dedicated Barbary Macaque bite protocol). In the UK, dial 999 or 111 (UKHSA Rabies and Monkey B Virus Service); across the EU, dial 112.
  • Japan, Hong Kong, Singapore, and Malaysia: Dial 119 in Japan, 999 in Hong Kong (Queen Elizabeth / Prince of Wales A&E) and Malaysia, or 995 in Singapore (Tan Tock Seng Hospital / National Centre for Infectious Diseases [NCID]).
  • United States & Global Herpes B Reference Laboratory: Call 911 for emergencies. Physicians worldwide can consult the National B Virus Resource Center at Georgia State University (Atlanta, USA) 24/7 Emergency Hotline at +1-404-413-6550 or the CDC Emergency Operations Center (+1-770-488-7100) for PCR/serology diagnostics and clinical antiviral guidance.

Frequently asked questions

Which monkeys carry Herpes B virus, and do all monkeys have it?

No, only Old World monkeys of the genus Macaca (macaques), including Rhesus macaques, Long-tailed (crab-eating) macaques, Japanese macaques, and Barbary macaques found across Bali, Thailand, India, Nepal, Malaysia, Singapore, Hong Kong, Japan, and Gibraltar, are natural reservoirs of Macacine alphaherpesvirus 1 (Herpes B virus), with 70 to 90 percent of adult macaques carrying it asymptomatically. Baboons, vervet monkeys, Asian langurs, and all Central and South American (New World) monkeys such as capuchins, squirrel monkeys, and marmosets do NOT naturally carry Herpes B virus, though they still require immediate Rabies Post-Exposure Prophylaxis and antibiotics.

Why is scrubbing a macaque bite or scratch for 15 minutes right away so critical?

Herpes B virus and rabies virus are surrounded by a fragile lipid (fat) envelope and remain on the surface skin cells for only a few minutes after a bite or scratch before binding to peripheral sensory nerves and traveling up into the spinal cord and brain. Once the virus enters the nerve axon, surface antiseptics can no longer reach it. Scrubbing the wound immediately for a full 15 minutes with povidone-iodine (Betadine), chlorhexidine, or concentrated detergent soap and running water dissolves the viral lipid envelope on contact and washes away over 99 percent of the virus before nerve invasion occurs.

What is the exact dose of Valacyclovir or Acyclovir needed to prevent Herpes B virus after a macaque bite?

Because Herpes B virus is roughly 10 times less sensitive to antivirals than human cold-sore herpes (HSV-1), a standard low-dose cold-sore prescription is not sufficient. According to CDC Herpes B Virus Working Group guidelines, adults require oral Valacyclovir 1,000 mg (1 gram) taken three times daily (every 8 hours) for 14 full days, or alternatively oral Acyclovir 800 mg taken five times daily for 14 days, started ideally within 24 to 72 hours of the bite, scratch, or eye splash.

What should I do if a macaque monkey spits or splashes water into my eye?

Ocular splashes of macaque saliva or cage/pool water are a documented route of fatal human Herpes B virus transmission via the conjunctiva and optic/trigeminal nerves. Do NOT put soap, povidone-iodine, or alcohol into your eye; instead, hold your eyelids open and flush the eye continuously for 15 full minutes with clean bottled drinking water or sterile 0.9% normal saline, then go immediately to a hospital to start oral Valacyclovir (1 g three times daily for 14 days) and discuss rabies prophylaxis.

Do I still need Rabies Immune Globulin (HRIG) if I get the rabies vaccine on the day of the monkey bite?

Yes, if you have never received pre-exposure rabies vaccinations before the trip, every skin-breaking monkey bite or scratch in a rabies-endemic country (such as Indonesia/Bali, Thailand, India, Nepal, Africa, or Latin America) is a WHO Category III exposure requiring BOTH the 4-dose rabies vaccine series AND passive Human Rabies Immune Globulin (HRIG, 20 IU/kg) infiltrated directly into and around the wound. Because the rabies vaccine takes 7 to 14 days to stimulate your immune system to make its own antibodies, HRIG provides immediate neutralizing antibodies right at the bite site during that dangerous first week.

What warning symptoms during the first 30 days after a macaque bite mean I need emergency IV treatment?

Seek immediate emergency hospital admission for intravenous Ganciclovir (5 mg/kg IV every 12 hours) or high-dose IV Acyclovir if you develop any of the following within 3 to 30 days of a macaque exposure: fluid-filled blisters or ulcers near the wound; burning, tingling, numbness, or severe itching radiating up the bitten arm or leg; unexplained fever or severe headache; persistent intractable hiccups (a classic sign of Herpes B brainstem inflammation); double vision, dizziness, difficulty swallowing, or limb weakness.

Sources and official guidance

  • Centers for Disease Control and Prevention (CDC, United States): CDC Yellow Book (Health Information for International Travel): Zoonotic Exposures: Bites, Scratches, and Other Hazards from Macaque Monkeys (Herpes B Virus / Macacine alphaherpesvirus 1) and Rabies.
  • Cohen, J. I., Davenport, D. S., Stewart, J. A., et al. (B Virus Working Group, Clinical Infectious Diseases / CDC): Recommendations for Prevention of and Therapy for Exposure to B Virus (Cercopithecine Herpesvirus 1).
  • National B Virus Resource Center (Georgia State University, Atlanta, USA): Emergency Standard Operating Procedures for Macaque Bite/Scratch Decontamination, Diagnostic Testing, and Post-Exposure Prophylaxis.
  • World Health Organization (WHO): WHO Expert Consultation on Rabies: Category III Exposure Management, Local Wound Infiltration of Rabies Immunoglobulin (HRIG/ERIG), and Vaccine Schedules.
  • Infectious Diseases Society of America (IDSA): Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections Following Non-Human Primate Bites.