Herpes B Virus Infection
B virus infection (herpesvirus simiae, or Macacine alphaherpesvirus 1) is a rare but highly dangerous acute zoonosis passed from monkeys to humans, mainly from macaques of the genus Macaca (long-tailed and rhesus macaques). B virus belongs to the family Herpesviridae and resembles human herpes simplex virus (HSV) in structure and biology, but it is far more neurotoxic in humans. In monkeys it causes only mild mucosal blisters or silent latent infection. Once it enters a person through a bite, a scratch or contact with secretions, however, it attacks the peripheral and central nervous system directly, causing ascending necrotizing encephalomyelitis with a death rate above 70–80% without prompt post-exposure prophylaxis (PEP).
At Haute-Derma, a possible B virus exposure is handled with a strict protocol: urgent high-volume wound irrigation, PCR sampling, immediate high-dose antiviral treatment and, once the danger has passed, cosmetic repair of the skin.
Pathophysiology
Source of Infection and Route of Entry
- Natural hosts: macaque monkeys (Macaca mulatta, Macaca fascicularis). Up to 80–90% of adult animals in a troop may carry the virus in latent form.
- Transmission: The virus is present in the monkey's saliva, oral, eye and genital secretions, and nerve tissue. It reaches humans through bites, deep scratches, needles or lab equipment contaminated with monkey secretions, or splashes onto the eyes, nose or mouth.
Neurotropism and Destruction of the Central Nervous System
- Replication in the skin and entry into nerve endings: The virus first multiplies in the epidermal and dermal cells at the wound, causing local necrotic blisters. It then attaches to peripheral sensory nerve endings.
- Retrograde axonal transport: B virus travels back up the nerve fibers to the dorsal root ganglion that serves the bitten dermatome.
- Hemorrhagic necrotizing encephalomyelitis: The virus continues up into the spinal cord and brain, causing necrotizing inflammation of brain tissue and widespread demyelination, which leads to sudden brain swelling, respiratory failure and death.
Clinical Stages of the Disease
Skin Lesions and Early Warning Symptoms at the Bite Site
- Incubation period: 2 days to 5 weeks after exposure (most often 1–3 weeks).
- Local skin lesions: Clusters of small vesicles on a red base appear right at the healed bite or scratch, quickly breaking down into shallow ulcers or crusts.
- Localized abnormal sensation: Intense itching, numbness, burning pain or heightened sensitivity to pain (hyperesthesia) in the skin around the wound.
Neurological Phase and Progressive Encephalomyelitis
- Early systemic symptoms: High fever, chills, severe headache, muscle aches, fatigue and tender swollen lymph nodes draining the area.
- Central nervous system signs:
- Spinal cord involvement: numbness and paralysis spreading from the bitten limb up the trunk, muscle weakness, loss of coordination (ataxia) and urinary retention.
- Brain involvement: neck stiffness, cranial nerve palsies, visual disturbance, seizures, respiratory failure from diaphragm paralysis, and deep coma.
Differential Diagnosis of Viral Infections After Animal Bites
| B Virus Infection (Macacine alphaherpesvirus 1) | Rabies (Rabies lyssavirus) | Herpes Simplex (HSV-1 / HSV-2) |
|---|---|---|
| Macaques (bites, scratches, secretions) | Dogs, cats, bats, monkeys | Person-to-person contact |
| Clustered blisters, shallow ulcers | Bite heals normally | Clustered blisters that heal on their own |
| Abnormal sensation, itch/burning along the dermatome | Abnormal sensation, intense itch at the scar | Superficial local burning |
| Progressive myelitis, ascending paralysis | Fear of water and drafts, throat spasms | No encephalomyelitis (in healthy people) |
Emergency Care and Diagnosis at Haute-Derma
Emergency High-Volume Wound Cleansing (the 15–20 Minute Rule)
- Irrigate the wound continuously under running water with antiseptic soap or povidone-iodine/chlorhexidine solution for a full 15–20 minutes. This is the single most important step for removing most of the virus from the skin.
- Mucosal rinse (for splashes to the eyes or nose): flush with 0.9% saline or clean water continuously for 15 minutes.
- Warning: Do not close the wound with stitches, and do not apply irritating substances of unknown origin.
Urgent Microbiological Testing
- Swabs are taken from blister fluid, the bite wound or the mucosa.
- PCR detects Macacine alphaherpesvirus 1 DNA, and serology (ELISA/Western blot) screens for antibodies.
- Highly suspected cases are referred to a facility with appropriate biosafety capability.
Post-Exposure Prophylaxis (PEP) and Cosmetic Recovery at Haute-Derma
Antiviral Post-Exposure Prophylaxis (PEP)
- Start immediately, within hours of a bite or high-risk exposure to secretions, without waiting for test results:
- Preferred options (oral, for 14 days):
- Valacyclovir 1 g orally three times daily (every 8 hours) for 14 days.
- Or acyclovir 800 mg orally five times daily for 14 days.
- Preferred options (oral, for 14 days):
- Once clinical or neurological symptoms appear (emergency inpatient care):
- Ganciclovir 5 mg/kg IV every 12 hours.
- Or acyclovir 12–15 mg/kg IV every 8 hours until symptoms resolve, then switch to an oral maintenance regimen.
Skin Repair and Cosmetic Scar Recovery
- After the patient has safely completed PEP and microbiology tests are negative:
- Apply a solution containing epidermal growth factor (EGF), madecassoside and hyaluronic acid to help the blister-damaged epidermis regenerate.
- Short-pulse fractional CO₂ laser, combined with a niacinamide/azelaic acid serum, smooths scar edges, rebuilds collagen and fades post-inflammatory hyperpigmentation (PIH).
