[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Human herpesviruses](https://durgical.com/en/microbiology/groups/human-herpesviruses/) › B virus # B virus - Virus - Enveloped - For completeness A herpesvirus that macaque monkeys carry harmlessly. In people, a bite or scratch can rarely lead to a brain and spinal cord infection that is often fatal. Updated Nov 13, 2026 Also called: Macacine alphaherpesvirus 1, herpes B, monkey B virus, herpesvirus simiae ## Quick facts **Type** Virus · [Human herpesviruses](https://durgical.com/en/microbiology/groups/human-herpesviruses/) **Gram / shape** Icosahedral capsid inside a tegument and envelope **Spread** Bite or scratch from a macaque · Monkey saliva **Causes** Infection after a monkey bite or scratch **Treatment** Antiviral nucleoside analogues On this page - The basics Key points - At a glance - Morphology - Transmission - Memory aid - What the colours mean - Clinical Virulence factors - Diseases it causes - Clinical picture - Diagnosis - Treatment Treatment - Prevention - Study Test yourself - Connections Connections ## Key points - Alphaherpesvirus of macaques: harmless in monkeys, often fatal in humans - Spread by bite, scratch, splash or needle stick from a macaque - Thorough 15-minute wash of the wound comes first - Antiviral prophylaxis after high-risk exposures; intravenous antivirals for disease - Ascending paralysis with respiratory failure is the usual cause of death ## At a glance **Shape** Icosahedral capsid inside a tegument and envelope **Genome** Double-stranded, linear DNA **Envelope** Enveloped **Family** Orthoherpesviridae (alphaherpesvirus subfamily), genus Simplexvirus **Size** About 150 to 200 nm ## Morphology - Closely related to herpes simplex viruses 1 and 2, with which it cross-reacts in antibody tests - Like other alphaherpesviruses it becomes latent in sensory nerve ganglia of its natural host ## Transmission - Bite or scratch from a macaque (rhesus, pig-tailed, cynomolgus) - Monkey saliva, tissue or fluids on broken skin, eyes, nose or mouth - Needle sticks and cuts from contaminated cages or equipment; handling monkey brain, spinal cord or skull - Person-to-person spread has been documented only once **Reservoir:** Macaque monkeys: most adult animals carry the virus, usually without signs, and shed it intermittently like HSV in humans ### Isolation precautions What the care team adds to standard precautions. - Standard ## Virulence factors - In macaques it causes mild oral or genital lesions, as HSV does in people - In humans it replicates at the entry site, then travels along peripheral nerves to the spinal cord and brain - Ascending myelitis and encephalomyelitis lead to respiratory failure, the usual cause of death ## Diseases it causes - B virus encephalomyelitis after macaque exposure [Viral encephalitis (herpes simplex encephalitis) →](https://durgical.com/en/conditions/viral-encephalitis/) - Infection after a monkey bite or scratch [Mammalian bites (dog, cat, human) →](https://durgical.com/en/conditions/mammalian-bites/) ## Clinical picture - Incubation usually under a month, sometimes as short as 3 to 7 days - Early: flu-like fever, myalgia, fatigue, headache; vesicles, pain or itching at the wound; regional lymphadenitis - Neurological: numbness near the wound, ataxia, diplopia, agitation, then ascending paralysis - Death can follow 1 day to 3 weeks after symptoms start; survivors often keep severe neurological deficits ## Diagnosis - Exposure history is the key clue: any macaque bite, scratch or splash in a lab, zoo, temple or tourist site - Serology and virus detection (PCR) in reference laboratories; HSV cross-reactivity complicates antibody tests - Swabs from the wound and the monkey, plus CSF and blood if symptoms appear ## Treatment Antiviral nucleoside analogues: valaciclovir or aciclovir as post-exposure prophylaxis after a high-risk exposure; intravenous aciclovir or ganciclovir once disease is suspected, especially with neurological signs. Prompt wound cleansing matters most. Drug class only; doses and regimens are set by the clinician from the current guideline. In Pharmacology: - [Valaciclovir](https://durgical.com/en/pharmacology/valaciclovir/) - [Aciclovir](https://durgical.com/en/pharmacology/aciclovir/) - [Ganciclovir](https://durgical.com/en/pharmacology/ganciclovir/) ## Prevention - Immediate first aid: wash skin with soap, povidone-iodine or chlorhexidine and rinse eyes or mucosa with water or saline for about 15 minutes - Protective equipment and safe handling protocols for lab and animal workers - Do not touch or feed monkeys at tourist sites - No vaccine exists ## Memory aid "B for Bite, B for Brain": a macaque bite plus neurological signs near the wound should make you think of B virus. ## Test yourself Think of the answer, then tap the question to see it. ## Which animal is the natural host of B virus? Macaque monkeys (such as rhesus and cynomolgus), which usually carry it without illness. ## What is the first step after a macaque bite in a laboratory? Wash the wound thoroughly for about 15 minutes (soap, povidone-iodine or chlorhexidine), then seek medical evaluation for antiviral prophylaxis. ## What usually causes death in B virus infection? Respiratory failure from ascending paralysis caused by encephalomyelitis. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/b-virus/) ## What the colours mean **Gram-positive** Thick peptidoglycan wall: stains purple. **Gram-negative** Thin wall with an outer membrane: stains pink. **Acid-fast** Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain. ## Connections ## Related 3 - [Herpes simplex virus 1](https://durgical.com/en/microbiology/herpes-simplex-virus-1/) - [Herpes simplex virus 2](https://durgical.com/en/microbiology/herpes-simplex-virus-2/) - [Rabies virus](https://durgical.com/en/microbiology/rabies-virus/) ## Related conditions 2 - [Viral encephalitis (herpes simplex encephalitis)](https://durgical.com/en/conditions/viral-encephalitis/) - [Mammalian bites (dog, cat, human)](https://durgical.com/en/conditions/mammalian-bites/) [← Back to the group: Human herpesviruses](https://durgical.com/en/microbiology/groups/human-herpesviruses/) Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [About B Virus](https://www.cdc.gov/herpes-b-virus/about/index.html) (CDC, 2024); [Clinical Overview of B Virus](https://www.cdc.gov/herpes-b-virus/hcp/clinical-overview/index.html) (CDC, 2024). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/microbiology/b-virus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/b-virus/