[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other DNA viruses](https://durgical.com/en/microbiology/groups/other-dna-viruses/) › Mpox virus [Microbiology](https://durgical.com/en/microbiology/) · [Other DNA viruses](https://durgical.com/en/microbiology/groups/other-dna-viruses/) # Mpox virus - Virus - Enveloped - Contact - Airborne - Exam priority: medium A poxvirus that causes skin and mucosal lesions with swollen lymph nodes; it caused worldwide outbreaks in 2022 and 2024. Updated 2026-11-01 Also called: mpox, monkeypox ## Key points - Mpox has prominent lymphadenopathy; smallpox does not. - 2022: worldwide outbreak from clade IIb; 2024: a new international emergency from clade Ib. - Diagnosis by lesion PCR; always test for HIV and STIs. - In hospital: contact precautions plus an N95 respirator and eye protection. ## At a glance **Shape** Large, brick-shaped, enveloped **Genome** Linear double-stranded DNA **Envelope** Enveloped **Family** Poxviridae (genus Orthopoxvirus) **Size** About 200 to 250 nm ## Morphology - Large brick-shaped virus - Replicates in the cytoplasm with its own machinery (cytoplasmic inclusion bodies) - Two clades: I (Ia, Ib) and II (IIa, IIb) ## Transmission - Close skin-to-skin, mouth-to-skin and face-to-face contact, including sex - Contaminated objects (bedding, towels) - Mother to fetus or newborn - Infected animals (rodents) in endemic areas of Africa **Reservoir:** African rodents (probable); Humans during outbreaks ### Isolation precautions What the care team adds to standard precautions. **Contact** Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing. **Airborne** N95 respirator and a negative-pressure room. ## Virulence factors - Proteins that block interferon and complement - Clade I has historically been linked to higher fatality than clade II ## Diseases it causes - Mpox [Mpox →](https://durgical.com/en/conditions/mpox/) ## Clinical picture - Fever, headache, muscle aches and prominent lymphadenopathy - Lesions moving from macule to papule, vesicle, umbilicated pustule and crust; in 2022 often anogenital and oral - Proctitis and severe pain from mucosal lesions that may not be visible - Symptoms start 1 to 21 days after exposure and last 2 to 4 weeks ## Diagnosis - PCR of lesion material (including lesions in the mouth, anus or vagina) - Testing for HIV and other sexually transmitted infections, because another STI does not rule out mpox ## Treatment Supportive care and early pain control. Tecovirimat, approved for smallpox, is kept for severe disease or high-risk patients, although clinical trials have not shown a clear benefit. Drug class only; doses and regimens are set by the clinician from the current guideline. ## Prevention - Non-replicating modified vaccinia (MVA) vaccine for high-risk people and after exposure - Avoiding close contact with people who have lesions - In hospital: single room, gown, gloves, eye protection and an N95 respirator; an airborne isolation room for aerosol-generating procedures **Vaccine:** Non-replicating MVA vaccine, aimed at high-risk groups and contacts; not part of the routine PAI schedule. ## In Colombia Colombia confirmed its first cases in June 2022 and was among the most affected countries in the Americas, mainly in adult men. Bogotá alone confirmed about 2,000 cases, with a peak between August and October 2022. It is an INS surveillance event. ## Memory aid If the pustules bring lymph nodes, think mpox; if they arrive all at once with no nodes, think of the smallpox of history books. ## Test yourself Think of the answer, then tap the question to see it. ## Which clinical finding helps tell mpox from smallpox? Prominent lymphadenopathy, present in mpox and absent in smallpox. ## Which clade caused the 2022 worldwide mpox outbreak? Clade IIb, spread mostly through close and sexual contact. ## Which protective equipment do health workers use with an mpox patient? Gown, gloves, eye protection and an N95 respirator, in a single room. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/mpox-virus/) ## Related - [Variola virus](https://durgical.com/en/microbiology/variola-virus/) - [Molluscum contagiosum virus](https://durgical.com/en/microbiology/molluscum-contagiosum-virus/) ## Related conditions - [Mpox](https://durgical.com/en/conditions/mpox/) ## 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. **Contact** Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing. **Droplet** Surgical mask within about a metre; single room. **Airborne** N95 respirator and a negative-pressure room. [← Back to the group: Other DNA viruses](https://durgical.com/en/microbiology/groups/other-dna-viruses/) Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Mpox](https://www.who.int/news-room/fact-sheets/detail/mpox) (WHO, 2025); [Clinical Overview of Clade I and Clade II Monkeypox](https://www.cdc.gov/monkeypox/hcp/clinical-overview/index.html) (CDC, 2025); [Infection Prevention and Control in Healthcare Settings](https://www.cdc.gov/monkeypox/hcp/infection-control/healthcare-settings.html) (CDC, 2025); [Bogotá no presenta casos activos de viruela símica o del mono: Sec. de Salud](https://bogota.gov.co/mi-ciudad/salud/bogota-no-tiene-casos-activos-de-viruela-simica-con-corte-marzo-2023) (Alcaldía de Bogotá, 2023). ## **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/mpox-virus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/mpox-virus/