Monkeypox (Mpox) is a rare viral disease that is similar to smallpox but is less severe. It was first identified in 1958 when outbreaks occurred in monkeys kept for research. The disease is caused by the monkeypox virus, which is a member of the orthopoxvirus genus[1], the same genus as the smallpox virus. Symptoms include fever, swollen lymph nodes, and a rash that forms blisters and then crusts over. The time from exposure to onset of symptoms ranges from five to twenty-one days. The duration of symptoms is typically two to four weeks.
Transmission of the monkeypox virus to humans can occur via animal bite or direct contact with the blood, meat, bodily fluids, cutaneous, or mucosal lesions of an infected animal. Human-to-human transmission by close direct contact and via exhaled large droplets is rare but can occur. The symptoms of monkeypox usually begin with fever, headache, muscle aches, backache, swollen lymph nodes, chills, and exhaustion.
Monkeypox Spread
- to persons, through touch, kissing, or sex
- animals, when hunting, skinning, or cooking
- materials, such as contaminated sheets, clothes, or needles
- pregnant persons may pass the virus on to their unborn baby.
The virus then enters the body through broken skin, mucosal surfaces (e g oral, pharyngeal, ocular, genital, anorectal), or via the respiratory tract. Mpox can spread to other members of the household and to sex partners. People with multiple sexual partners are at higher risk. Animal-to-human transmission of mpox occurs from infected animals to humans from 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 contract mpox from contaminated objects such as clothing or linens, through sharps injuries in health care, or in a community setting such as tattoo parlors.
A rash then develops, often beginning on the face and then spreading to other parts of the body. The rash progresses to form fluid-filled blisters that later crust over and scab. The disease usually lasts for 2-4 weeks, with complete recovery in most cases. However, severe cases can occur, particularly in individuals with weakened immune systems. Although the evidence is limited and the risk of human-to-human transmission appears to be low, researchers report that infants and young children appear to be at the greatest risk of severe disease.
For some people, the first symptom of mpox is a rash, while others may have different symptoms first. The rash begins as a flat sore which develops into a blister filled with liquid and may be itchy or painful. As the rash heals, the lesions dry up, crust over, and fall off. Some people may have one or a few skin lesions and others have hundreds or more. These can appear anywhere on the body such as:
- palms of hands and soles of feet
- face, mouth, and throat
- groin and genital areas
- anus
Some people also have painful swelling of their rectum or pain and difficulty when peeing.
The World Health Organization (WHO) reports that transmission from the mother to the fetus can occur via the placenta (which can lead to congenital monkeypox) or by close contact during and after birth.
The monkeypox rash progresses through sequential stages
- Macules—small spots, different in color from the surrounding tissue
- Papules—small circumscribed solid elevations on the skin
- Vesicles—small, circumscribed elevations on the skin containing fluid
- Pustules—small, circumscribed elevations of the skin containing purulent material
- Scabs—crust formed by coagulation of blood, pus, serum, or a combination
The rash can last up to a month. The rash can also be confused with other diseases that are more commonly encountered in clinical practice (e.g., secondary syphilis, herpes, and varicella zoster). Researchers report some patients are co-infected with the monkeypox virus and other infectious agents (e.g., varicella zoster or syphilis). Patients with a characteristic rash should be advised to receive testing.
Monkeypox and syphilis are two separate conditions caused by different infectious agents. Monkeypox is caused by the monkeypox virus, while syphilis is caused by the bacterium Treponema pallidum. There is no evidence to suggest that monkeypox can evolve into syphilis. However, it is possible for an individual to be co-infected with both monkeypox and syphilis or to have a rash caused by syphilis that is mistaken for monkeypox. Testing is always required to determine the cause of a rash, and treatment will depend on the specific diagnosis.
Do
- stay home and in your own room if possible
- wash hands often with soap and water or hand sanitizer, especially before or after touching sores
- wear a mask and cover lesions when around other people until your rash heals
- keep skin dry and uncovered (unless in a room with someone else)
- avoid touching items in shared spaces and disinfect shared spaces frequently
- use saltwater rinses for sores in the mouth
- take sitz baths or warm baths with baking soda or Epsom salts for body sores
- take over-the-counter medications for pain like paracetamol (acetaminophen) or ibuprofen.
Do Not
- pop blisters or scratch sores, which can slow healing, spread the rash to other parts of the body, and cause sores to become infected; or
- shave areas with sores until scabs have healed and you have new skin underneath (this can spread the rash to other parts of the body).
There is no known cure. A study in 1988 found that the smallpox vaccine was around 85% protective in preventing infection in close contact and in lessening the severity of the disease. A newer smallpox and mpox vaccine based on modified vaccinia Ankara has been approved but with limited availability.
Patients not requiring hospitalization but who are potentially infectious should home isolate is one potential impact of monkeypox on health. In general, individuals diagnosed with monkeypox who do not require hospitalization should be instructed to self-isolate at home to prevent further spread of the virus. The need for hospitalization in monkeypox cases is generally related to the severity of the illness and the need for supportive care, such as pain management, hydration, and management of complications. Behavioral consults are not typically required for monkeypox cases. Discontinuation of isolation should be determined in consultation with a healthcare provider and public health authorities, not a respiratory therapist.
Other measures include regular hand washing and avoiding sick people and animals. Antiviral drugs, cidofovir and tecovirimat, vaccinia immune globulin, and the smallpox vaccine may be used during outbreaks. The illness is usually mild and most of those infected will recover within a few weeks without treatment.
TPOXX is the vaccine indicated for the prevention of monkeypox in adults 18 years or older who are determined to be at high risk for infection. TPOXX is a smallpox vaccine that has been approved by the US Food and Drug Administration (FDA) for the prevention of monkeypox in adults who are at high risk of exposure to the virus.
Tecovirimat is the therapeutic that is stockpiled by the U.S. government, has an EA-IND, and was found to have in vitro activity against seven monkeypox strains.
It is not recommended for routine use in the general population, and its use should be determined in consultation with public health authorities. VIGIV, is not a vaccine but rather an immunoglobulin product used to treat individuals with severe complications from smallpox vaccination.
JYNNEOS, is a vaccine that provides protection against both smallpox and monkeypox, but it is not currently recommended for routine use in the general population. It may be used in special circumstances, such as for individuals at high risk of exposure to viruses or for emergency response purposes.
Anaphylactic reactions after dosing are possible with the smallpox and monkeypox vaccines (JYNNEOS). Anaphylaxis is a rare but serious side effect that can occur after vaccination, and it is important for healthcare providers to be prepared to treat anaphylaxis promptly if it occurs.
Estimates of the risk of death vary from 1% to 10%, although few deaths as a consequence of mpox have been recorded since 2017. The first cases in humans were found in 1970 in the Democratic Republic of the Congo (DRC). There have been sporadic cases in Central and West Africa, and it is endemic in the DRC.
The 2022 mpox outbreak represents the first incidence of widespread community transmission outside of Africa, which was initially identified in the United Kingdom in May 2022, with subsequent cases confirmed in at least 74 countries in all continents except Antarctica.
Monkeypox and HIV
Individuals infected with HIV (Human Immunodeficiency Virus) may be at an increased risk of developing severe monkeypox disease if they are infected with the monkeypox virus. HIV infection can impair the immune system and make it more difficult for the body to fight off infections, including monkeypox.
People with HIV who are infected with monkeypox may be more likely to experience severe symptoms, including a higher risk of death. One study conducted in the Democratic Republic of Congo found that individuals with HIV who were infected with monkeypox were more likely to experience severe symptoms and had a higher risk of death compared to individuals without HIV.
The study also found that people with HIV who were infected with monkeypox were more likely to experience recurrent or persistent infection, indicating that their immune system was not able to effectively clear the virus from their body. Another study conducted in Nigeria found that individuals with HIV who were infected with monkeypox were more likely to experience severe symptoms and had a higher risk of death compared to individuals without HIV.
The study also found that people with HIV who were infected with monkeypox were more likely to experience complications such as sepsis and pneumonia. It is important for people living with HIV to take steps to reduce their risk of exposure to monkeypox, including avoiding contact with sick animals and taking precautions when caring for individuals who are infected with the virus.
Vaccination with the smallpox and monkeypox vaccine (JYNNEOS) may be recommended for people at high risk of exposure, including healthcare workers, laboratory personnel, and individuals living in areas where monkeypox is known to occur.
Footnotes
- The Orthopoxvirus genus is a group of large, double-stranded DNA viruses that belong to the family Poxviridae. The genus includes several important human and animal pathogens, such as smallpox virus, monkeypox virus, cowpox virus, and vaccinia virus. These viruses are highly infectious and can cause a wide range of clinical manifestations, from mild skin lesions to severe systemic infections. The orthopoxviruses are also known for their ability to induce protective immunity, which has made them attractive candidates for use as vaccines and in cancer immunotherapy. Despite the eradication of smallpox, orthopoxviruses continue to pose a threat to human and animal health, and research on their biology, pathogenesis, and immunity remains important. [Back]
Further Reading
Sources
- “Mpox (monkeypox)” – World Health Organization
- “Mpox” – Wikipedia
- Rimoin AW, Mulembakani PM, Johnston SC, et al. Major increase in human monkeypox incidence 30 years after smallpox vaccination campaigns cease in the Democratic Republic of Congo. Proc Natl Acad Sci U S A. 2010;107(37):16262-16267. doi:10.1073/pnas.1005769107
- Nolen LD, Osadebe L, Katomba J, et al. Extended Human-to-Human Transmission during a Monkeypox Outbreak in the Democratic Republic of the Congo. Emerg Infect Dis. 2016;22(6):1014-1021. doi:10.3201/eid2206.151839
- Centers for Disease Control and Prevention. (2021). Monkeypox. https://www.cdc.gov/poxvirus/monkeypox/index.html
- World Health Organization. (2020). Monkeypox. https://www.who.int/news-room/fact-sheets/detail/monkeypox
- Osadebe, L. U., et al. (2021). Monkeypox: An Overview of Pathogenesis, Diagnosis, Prevention, and Treatment. Infectious Disease Clinics of North America, 35(1), 215-229. https://doi.org/10.1016/j.idc.2020.09.004
