About Mpox

A resurgence of human mpox (formerly known as monkeypox) virus infections were reported in Chicago and suburban Cook County starting in March of 2023. Illinois Department of Public Health (IDPH) continues to urge those at-risk for mpox exposure to take precautions and to get vaccinated, if they are not already, ahead of the spring and summer festival and Pride season.

Initial outbreaks of reported Mpox cases in May of 2022 were seen in Europe and first reported case in the United State (Massachusetts) were identified where the infected individual had not traveled to Africa where previous exposed mpox outbreaks were identified. Some of the outbreaks have patients who identify as gay, bisexual, or other same gender loving men. These outbreaks are currently under investigation and more information is expected in the future. Therefore, health care providers in Illinois should be alert for any suspect cases, even if the patient has not traveled but has an illness suspected to be Mpox. These cases should be promptly reported to their local health department. Requests for testing should be made through the local health department.

Mpox is rare and does not spread easily between people typically without close contact like skin-to-skin or face-to-face. Data currently show transmission is higher among people in close sexual networks, however, anyone in close contact like face-to-face (such as prolong hugging, cuddling, kissing) or skin-to-skin (such as prolong body contact) to any infected person may get the infection.

Mpox as it’s called in the latest development of this rare disease caused by infection with the mpox virus. Mpox virus belongs to the Orthopoxvirus genus in the family Poxviridae. Mpox is not related to chickenpox.

First discovered in monkeys with pox-like disease in 1958. Despite being named “monkeypox”, the source of the disease remains unknown. However, African rodents and non-human primates (like monkeys) may harbor the virus and infect people.

The first known human case of mpox was identified in 1970. Mpox can be found in animals (African rodents, monkeys, and other primates) and usually encountered in villages in west and central Africa. Historically, persons in Illinois could become infected by traveling to west and central Africa and being exposed to people or animals with the disease. One human outbreak in the U.S. in 2003 occurred when African rodents came in contact with pet prairie dogs at an Illinois animal vendor. Some persons in contact with the infected prairie dogs developed mpox, including 10 Illinois residents.

There are two types of mpox:

• clade I (with subclades Ia and Ib)
• clade II (with subclades IIa and IIb; IIb caused the ongoing global outbreak)

You cannot tell which type of mpox someone has by looking at them. Outbreaks associated with the different subclades can have different characteristics, like who they affect, how they are spread, or how sick people can get. People with mpox often get a rash that may be located on hands, feet, chest, face, mouth, or near the genitals, including the penis, testicles, labia, vagina, and anus. The incubation period is 3–17 days. During this time, a person does not have symptoms and may feel fine.

Although clade II mpox has been circulating in the United States since 2022, clade I mpox has never been reported in the United States before now. Illinois has not had a case of clade I mpox. The first known case of clade I mpox in the United States was confirmed in California in November 2024. This case is related to an ongoing outbreak of clade I mpox in Central and Eastern Africa. The anticipated overall risk of clade I mpox to the general population in the United States from the outbreak in Central and Eastern Africa is low. Close-contact transmissions within and between households are unlikely to result in a large number of clade I mpox cases in the United States, or Illinois.

Casual contact, like you might have during travel or being in the same room as someone with mpox for a short time, is unlikely to pose significant risks for transmission of mpox. CDC issued guidance for travelers to Central and Eastern Africa countries experiencing outbreaks earlier this year.

While investigations continue, CDC guidance has not changed.

If there is a suspect case with travel to Central and Eastern Africa in the past 21 days, IDPH should be immediately contacted for guidance on clade-specific testing. Providers should order testing through commercial labs as usual if there is no travel history.

Protect yourself from mpox by:

• Avoiding close contact, especially skin-to-skin, with people who are sick with symptoms of mpox, including those with skin or genital lesions
• Avoiding contact with contaminated materials used by people who are sick (such as clothing, bedding, toothbrushes, sex toys, or materials used in health care settings)
• Getting both recommended doses of mpox vaccine if you are eligible and have not been vaccinated

*People in the United States who have already had mpox or are fully vaccinated should be protected against the type of mpox spreading in the Democratic Republic of the Congo and neighboring countries.

Mpox is in the orthopox virus family, which includes cowpox and smallpox. Smallpox is no longer circulating in the world and was declared eradicated by the World Health Organization in 1980. Symptoms of mpox are milder than the symptoms of smallpox. The main difference between smallpox and mpox is that mpox causes lymph nodes to swell while smallpox does not. The incubation period for mpox is usually 7-14 days but can range from 5-21 days.

• Fever
• Headache
• Muscle aches
• Backache
• Swollen lymph nodes
• Chills
• Exhaustion

Within 1 to 3 days (sometimes longer) after the appearance of fever, the patient develops a rash, often beginning on the face and then spreading to other parts of the body or near certain areas like genitals, anus (butt), hands, feet, chest, or face. These sores can look like pimples and may be painful or itchy. They can be inside the body, including mouth, anus, or vagina. Note that a person is infectious the moment any of the above sign and symptoms start to appear.

The illness typically lasts for 2-4 weeks.

Photo credit: UK Health Security Agency as displayed on CDC’s website

Mpox may spread in different ways. The virus may spread from close contact like skin-to-skin or face-to-face through:

• Direct contact with infected skin rash, lesions, scabs, or body fluids
• Respiratory droplets during extended face-to-face contact, or during intimate physical contact, such as kissing, cuddling, or sex
  
• Contact with contaminated materials or objects (like clothing, towels, or linens) previously touched by infectious rash or body fluids
  
• Pregnant people may spread the virus to their fetus through the placenta
  

Individuals are infectious as soon as signs and symptoms appear.

People may get mpox from infected animals, either by being scratched or bitten by the infected animal or by preparing or eating meat or using products from an infected animal.

Anyone can get mpox. A lot of close contact with other people – skin-to-skin or face-to-face – can increase your risk. You can lower your risk by limiting your direct physical contact between yourself and others in crowded situations.

Rash, bumps, or blisters may appear anywhere on the body, including the genitals, however, you may not see or know of symptoms and can still spread the virus.

Here are some steps you may take to reduce risk:

• If you or your partners feel sick (flu-like symptoms, enlarged lymph nodes), especially if you or they have a new or unexpected rash or sores, or have been exposed, do not have sex or be in close physical contact with others or pets immediately and stay home. Avoid clubs, parties or gatherings until you have talked to a health care provider.
• If you choose to have sex while sick, avoid kissing and other face-to-face contact. Cover all sores and lesions with clothing or sealed bandages and wear a mask. This may help reduce – but not eliminate – the risk of transmission.
  
• Condoms (latex or polyurethane) may protect your anus, mouth, penis, or vagina from exposure to mpox. However, condoms alone may not prevent all exposures to mpox since the rash can occur on other parts of the body.
• Wash your hands, sex toys and bedding before and after sex or other intimate activities.
  
• Call (do not visit) to make an appointment to see a health care provider.
  

For more information regarding mpox, visit the CDC website or the World Health Organization.

• Travel Guidance (CDC)

• Mpox Comparison to COVID-19 and STIs
  
• Mpox Health Tips Infographic
• Mpox Health Tips Palm Card
• What You Need to Know About Mpox Infographic