What Is Monkeypox and Why the Name Change to Mpox
Monkeypox is a zoonotic viral disease caused by the monkeypox virus, a double-stranded DNA orthopoxvirus related to smallpox. Because the term “monkeypox” was perceived as stigmatizing to nonhuman primates and potentially misleading, the World Health Organization (WHO) recommended the synonym mpox in 2022 for both the disease and the virus. This naming shift aimed to reduce stigma while preserving clarity; the virus reservoir remains primarily rodents and small mammals, not monkeys. Understanding the virology, transmission routes, and clinical features is essential to distinguish mpox from other vesicular illnesses and to apply effective public health measures.
Key Attributes of Monkeypox (Mpox)
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Primary Reservoir | Rodents and small mammals in Central and West Africa | WHO, CDC |
| Disease Name (synonym) | Mpox adopted alongside monkeypox | WHO naming recommendation, 2022 |
| Genome Type | Double-stranded DNA | Virology literature |
| Case Milestone (global) | Over 87,000 confirmed cases reported to WHO by August 2024 since the 2022 multi-country outbreak | WHO situation reports |
| Fatality Range (CFR) for 2022–2023 outbreaks | Below 1% in non-endemic settings; higher in regions with limited care | WHO, CDC, ECDC |
| Vaccine Used Off-label | JYNNEOS (MVA-BN) initially licensed for smallpox | EMA, FDA |
Origin, Discovery, and Reservoirs
Monkeypox was first identified in 1958 in laboratory monkeys used for research, but the natural reservoir is small mammals, particularly rodents, in Central and West Africa. Zoonotic transmission occurs through contact with infected animals—handling, bites, or consumption—as well as via contaminated materials. Human-to-human spread happens through prolonged close contact with infectious lesions, bodily fluids, respiratory droplets, and, in some settings, fomites or intimate contact. Rodent-mediated spillover and human behaviors that increase exposure risk are central to the ecology of mpox.
Clinical Features and Stages
The illness typically begins with fever, headache, muscle aches, backache, swollen lymph nodes, and exhaustion, often progressing to a rash. The rash evolves through macules, papules, vesicles, pustules, and scabs, and can involve the face, palms, soles, and mucosal surfaces. Lesions may number in the thousands and can be painful or itchy. The illness is usually self-limited, lasting two to four weeks, but may be severe, especially in immunocompromised individuals, children, and pregnant people. Complications can include secondary infections, bronchopneumonia, sepsis, and corneal involvement leading to vision loss.
Clinical Course Overview
- Incubation: Typically 6–13 days, ranging 5–21 days
- Prodrome: Fever, lymphadenopathy, myalgia before rash onset
- Exanthema: Rash progresses through macule → papule → vesicle → pustule → crust
- Crusting and convalescence: Lesions fall off; patients are no longer infectious when all crusts have separated
Transmission, Risk Factors, and Settings
Transmission requires close contact with an infectious source—human, animal, or environmental. In the 2022 multi-country outbreak, many cases occurred through sexual networks, yet mpox is not exclusively a sexually transmitted infection; any close skin-to-skin or intimate contact can facilitate spread. Risk factors include prolonged face-to-face contact, household contacts, healthcare exposures, travel to endemic areas, and occupational contact with animals or specimens. Public health guidance emphasizes minimizing close contact with infectious cases, avoiding sharing linens or clothing, and practicing safe handling of garments and bedding.
Diagnosis, Testing, and Differential Considerations
Diagnosis is confirmed by nucleic acid amplification test (NAAT) on swabs from lesions, favoring PCR detection of orthopoxvirus and mpox-specific targets. Orthopoxvirus antigen tests and serology can support public health investigations but are less definitive for acute mpox. Clinicians should consider mpox in the differential for sexually transmitted infections that cause genital ulcers, as well as chickenpox, herpes, syphilis, and other vesiculobullous conditions. Early recognition and testing help guide isolation, contact tracing, and linkage to care.
Treatment, Vaccines, and Public Health Measures
Most people recover without specific treatment, but antivirals such as tecovirimat may be considered for severe cases or those at high risk. Vaccination with JYNNEOS (MVA-BN) can be used for post-exposure prophylaxis and pre-exposure protection in higher-risk groups. Non-pharmaceutical interventions include isolating until lesions crust and heal, using appropriate personal protective equipment, and environmental cleaning. Public health strategies focus on case investigation, contact tracing, vaccination rings, and risk communication to reduce onward spread while addressing stigma and ensuring equitable access to care.