Mpox(Monkeypox)

Mpox (previously known as monkeypox) is a zoonotic viral disease caused by the mpox virus (1). Though originally endemic to Africa, in 2022 a significant multi-country mpox outbreak arose in many countries throughout the world, driven by travel and person-to-person transmission. WHO and the United States have both declared the ongoing outbreak to be a public health emergency. Mpox and its causative virus were both originally named monkeypox as the virus was first detected in monkeys. In November 2022 WHO announced adoption of the name “mpox” as a new preferred synonym for monkeypox disease. Although official efforts to rename the virus are separate and technically still underway, many authorities, including the CDC, are now using the name mpox in reference to both the disease and the virus that causes it (2).

Mpox is closely related to smallpox and classically presents with a similar but milder clinical course (3). Initial symptoms can include fever, chills, headache, fatigue, joint and muscle pain, and swollen lymph nodes. A characteristic rash typically appears within several days, progressing through several different stages until lesions scab over and fall off. In the current outbreak, anogenital lesions have been very common, and symptoms other than rash are often very mild or absent altogether (4). Male to male sexual contact is believed to be the primary mode of disease transmission in the current outbreak (5). Transmission can occur through direct or indirect contact with mpox lesions, lesion material, respiratory secretions, other bodily fluids, and contaminated materials such as clothing and bedding (6).

Mpox should be suspected in patients with compatible clinical features (especially rash) and risk factors for exposure. Diagnosis is made via laboratory detection of virus DNA from lesion material (7). Most patients with mpox have mild, self-limited disease, and can be managed supportively. Several antiviral agents originally developed for the treatment of other viral infections appear effective against mpox and can be considered for certain patients (8). Additionally, in the United States, two vaccines are available for mpox pre- and post-exposure prophylaxis (9).

There have been relatively few deaths associated with the 2022 outbreak. Although the outbreak is still ongoing, case counts in the United States and worldwide have steadily declined since the latter half of 2022.

1. WHO: Monkeypox Fact Sheet. WHO website. Published May 19, 2022. Accessed January 5, 2023. https://www.who.int/news-room/fact-sheets/detail/monkeypox

2. WHO: News: WHO Recommends New Name for Monkeypox Disease. WHO website. Published November 28, 2022. Accessed January 5, 2023. https://www.who.int/news/item/28-11-2022-who-recommends-new-name-for-monkeypox-disease

3. Huhn GD et al: Clinical characteristics of human monkeypox, and risk factors for severe disease. Clin Infect Dis. 41(12):1742-51, 2005

4. CDC: Mpox: Healthcare Professionals: Clinical Guidance: Clinical Recognition. CDC website. Updated August 23, 2022. Accessed January 5, 2023. https://www.cdc.gov/poxvirus/monkeypox/clinicians/clinical-recognition.html

5. WHO: Multi-country Outbreak of Monkeypox, External Situation Report 5--7 September 2022. WHO website. Published September 7, 2022. Accessed January 5, 2023. https://www.who.int/publications/m/item/multi-country-outbreak-of-monkeypox--external-situation-report--5---7-september-2022

6. CDC: Mpox: How It Spreads. CDC website. Updated December 8, 2022. Accessed January 5, 2023. https://www.cdc.gov/poxvirus/monkeypox/transmission.html

7. CDC: Mpox: Healthcare Professionals: Case Definitions for Use in the 2022 Mpox Response. CDC website. Updated July 22, 2022. Accessed January 5, 2023. https://www.cdc.gov/poxvirus/monkeypox/clinicians/case-definition.html

8. CDC: Mpox: Healthcare Professionals: Clinical Guidance: Clinical Treatment. CDC website. Updated October 31, 2022. Accessed January 5, 2023. https://www.cdc.gov/poxvirus/monkeypox/clinicians/treatment.html

9. CDC: Mpox: Healthcare Professionals: Monkeypox and Smallpox Vaccine Guidance. CDC website. Reviewed October 19, 2022. Accessed January 5, 2023. https://www.cdc.gov/poxvirus/monkeypox/clinicians/smallpox-vaccine.html

10. WHO: Multi-country Outbreak of Monkeypox, External Situation Report #7 – 5 October 2022. WHO website. Published October 5, 2022. Accessed January 5, 2023. https://www.who.int/publications/m/item/multi-country-outbreak-of-monkeypox--external-situation-report--7---5-october-2022