Key Facts

• Mpox (monkeypox) is a viral illness caused by the monkeypox virus, a species of the genus Orthopoxvirus. There are two different clades: clade I and clade II.

• Common symptoms of mpox include a skin rash or mucosal lesions that can last 2–4 weeks, accompanied by fever, headache, muscle aches, back pain, low energy, and swollen lymph nodes.

• Mpox can be transmitted to humans through physical contact with an infectious person, contaminated materials, or infected animals.

• Prevention includes avoiding physical contact with infected individuals and vaccination for those at risk.

• Laboratory confirmation of mpox is done by testing skin lesion material using PCR.

• Treatment primarily involves supportive care, and vaccines and therapeutics developed for smallpox can be used for mpox in certain circumstances.

• A global outbreak of mpox occurred in 2022–2023, caused by a strain known as clade IIb.

Symptoms and Diagnosis

Mpox typically presents with a range of symptoms that can last from 2 to 4 weeks. Common symptoms include a skin rash or mucosal lesions, fever, headache, muscle aches, back pain, low energy, and swollen lymph nodes. The rash often begins as flat sores that develop into blisters filled with liquid, which may be itchy or painful. As the rash heals, the lesions dry up, crust over, and eventually fall off. The rash can appear anywhere on the body, including the palms of the hands, soles of the feet, face, mouth, throat, groin, genital areas, and anus.

In some cases, the first symptom of mpox is a rash, while others may experience different symptoms initially. The disease can cause complications such as bacterial infections of the skin, pneumonia, corneal infections leading to vision loss, difficulty swallowing, vomiting, diarrhea, severe dehydration, sepsis, encephalitis, myocarditis, proctitis, balanitis, urethritis, and even death. People with weakened immune systems, including those with uncontrolled or untreated HIV, are at higher risk of severe illness and death due to mpox.

Diagnosing mpox can be challenging as its symptoms can resemble other infections and conditions such as chickenpox, measles, bacterial skin infections, scabies, herpes, syphilis, and medication-associated allergies. Therefore, testing is crucial for accurate diagnosis and early treatment. The preferred laboratory test for mpox is the detection of viral DNA by polymerase chain reaction (PCR), using specimens taken directly from the rash, such as skin, fluid, or crusts collected by vigorous swabbing. In the absence of skin lesions, oropharyngeal, anal, or rectal swabs can be tested. Blood tests are not recommended, and antibody detection methods are not useful for distinguishing between different orthopoxviruses.

Transmission and Prevention

Mpox can be transmitted to humans through physical contact with an infected person, contaminated materials, or infected animals. Person-to-person transmission occurs through direct contact with infectious skin or other lesions, face-to-face contact (talking or breathing), skin-to-skin contact (touching or vaginal/anal sex), mouth-to-mouth contact (kissing), mouth-to-skin contact (oral sex or kissing the skin), and respiratory droplets or short-range aerosols from prolonged close contact. The virus can enter the body through broken skin, mucosal surfaces (e.g., oral, pharyngeal, ocular, genital, anorectal), or the respiratory tract.

Animal-to-human transmission occurs from infected animals to humans through bites or scratches, or during activities such as hunting, skinning, trapping, cooking, playing with carcasses, or eating animals. The extent of viral circulation in animal populations is not entirely known, and further studies are underway. People can also contract mpox from contaminated objects such as clothing or linens, through sharps injuries in healthcare settings, or in community settings such as tattoo parlors.

To prevent the spread of mpox, individuals with the disease should isolate at home or in a hospital if needed, for the duration of the infectious period (from the onset of symptoms until lesions have healed and scabs fall off). Covering lesions and wearing a medical mask when in the presence of others may help prevent spread. Using condoms during sex can reduce the risk of getting mpox but will not prevent spread from skin-to-skin or mouth-to-skin contact.

Treatment and Vaccination

The primary goal of treating mpox is to manage symptoms and prevent complications. Early and supportive care is crucial. Most people with mpox will recover within 2 to 4 weeks. To manage symptoms and prevent spreading the virus, individuals should stay home and isolate in their own room if possible, wash hands frequently with soap and water or hand sanitizer, wear a mask and cover lesions when around others, keep skin dry and uncovered unless in a shared space, avoid touching items in shared spaces and disinfect frequently, use saltwater rinses for mouth sores, take warm baths for body sores, and take over-the-counter pain medications like paracetamol or ibuprofen. It is important to avoid popping blisters or scratching sores, as this can slow healing and spread the rash.

Vaccination can help prevent mpox infection, especially for high-risk groups such as health workers, men who have sex with men, people with multiple sexual partners, and sex workers. The vaccine should ideally be administered within 4 days of exposure. Several antivirals, like tecovirimat, originally developed for smallpox, are being used to treat mpox, with further studies underway.

Historical Context and Recent Outbreaks

The monkeypox virus was first discovered in 1958 in monkeys kept for research, and the first reported human case was a nine-month-old boy in the Democratic Republic of the Congo (DRC) in 1970. Following the eradication of smallpox in 1980 and the end of smallpox vaccination worldwide, mpox steadily emerged in central, east, and west Africa. A significant outbreak occurred in the United States in 2003, linked to imported wild animals. Since 2005, thousands of suspected cases have been reported in the DRC every year. In 2017, mpox re-emerged in Nigeria and continues to spread between people across the country and in travelers to other destinations.

In May 2022, an outbreak of mpox appeared suddenly and rapidly spread across Europe, the Americas, and then all six WHO regions, with 110 countries reporting about 87 thousand cases and 112 deaths. The global outbreak has primarily affected gay, bisexual, and other men who have sex with men and has spread person-to-person through sexual networks. In 2022, outbreaks of mpox due to Clade I MPXV occurred in refugee camps in the Republic of the Sudan. A zoonotic origin has not been found.

WHO Response

The World Health Organization (WHO) declared the global mpox outbreak a public health emergency of international concern (PHEIC) on July 23, 2022. WHO has published a strategic preparedness and response plan, emphasizing surveillance, diagnostics, risk communication, and community engagement to stop the outbreak. The strategic preparedness and response plan includes a suite of technical guidance documents. Surveillance, diagnostics, risk communication, and community engagement remain central to stopping the outbreak and eliminating human-to-human transmission of mpox in all contexts.

Conclusion

Mpox is a serious viral illness that requires prompt diagnosis and treatment. Preventive measures, including vaccination and self-care practices, are essential to control the spread of the virus. Public health efforts and community engagement remain crucial in managing and eventually eliminating mpox transmission. By following recommended guidelines and staying informed, individuals and communities can help mitigate the impact of this infectious disease.