Mpox – Symptoms and Causes

What Is Mpox?

Mpox is an infectious disease caused by the monkeypox virus which results in a rash and flu-like symptoms. Mpox is part of the same family of viruses as variola virus, the virus that causes smallpox. There are two types of mpox, clade I and clade II. The global outbreak of mpox starting in 2022 was caused by clade II virus (which is endemic to West Africa) and cases continue to be reported in low levels in many countries today. Clade II mpox is considered a less severe form of the disease. More than 99% of people survived their infection in follow-up to the 2022 outbreak. The mpox outbreak starting in 2023 in the Democratic Republic of the Congo (DRC) with spread to neighboring countries in central and eastern Africa is caused by clade I virus. Clade I mpox usually causes more severe disease and more deaths than clade II. Clade I virus is endemic in DRC, but this current outbreak is more widespread than any prior outbreak and has spread to some neighboring countries (Burundi, Central African Republic, Republic of the Congo, Rwanda, Uganda, and a travel-associated case in Kenya). In August, the WHO declared the outbreak a Public Health Emergency of International Concern (PHEIC).

Mpox is currently spreading globally and within the United States primarily from close contact with an infected person, but historically has also been transmitted to people from contact with an infected animal.

Read more information about the current status of clade I and clade II mpox cases in the United States and worldwide from the Centers for Disease Control and Prevention (CDC)

How does mpox spread?

Mpox spreads when a person comes in contact with an animal or a person who has the virus. Transmission occurs through:

Direct contact with an infected person’s bodily fluids, sores, scabs or respiratory droplets. This can also occur through cuddling, kissing or sex.
Contact with recently contaminated materials exposed to skin lesions, including clothing or bedding.
Scratches or bites from an infected animal, preparing or eating meat or other products from an infected animal, or direct contact with an infected animal’s blood, bodily fluid or sores.

Mpox symptoms

After exposure to the mpox virus, the average incubation period is 1 to 2 weeks before symptoms appear.

Early signs of mpox include the following flu-like symptoms:

Chills
Exhaustion
Fever
Headache
Muscle aches and backache
Swollen lymph nodes

These flu-like symptoms are then typically followed by the development of a rash. The rash can look like pimples or blisters and can be painful. Lesions can appear on the face, in the mouth, and on the hands, feet, chest, genitals, or anus. Some people get the rash first, followed by other, flu-like symptoms, while some experience only a rash.

The rash goes through different stages, including pimple-like bumps and blisters that crust and fall off before healing completely. The illness caused by mpox typically lasts 2 to 4 weeks.

When to seek medical care for mpox symptoms

Call your health care provider if you have:

Fever, aches or swollen lymph nodes
A new rash or sores
Close contact with a person infected with mpox

Seek emergency medical care if you have:

A stiff neck
Chest pain
Confusion
Difficulty speaking
Loss of consciousness
Loss of mobility
Seizures
Trouble breathing

Prevention of mpox infection

Anyone can get mpox, but it can be prevented by limiting close contact with people with confirmed or suspected mpox and by vaccination.

Take the following precautions to help prevent mpox infection:

Avoid close contact with people who have been diagnosed with mpox or who have signs and symptoms of mpox, including fever and rash; this includes not sharing bedding, towels, and utensils used by the infected individual, which may be contaminated with the virus from skin lesions.
Clean and disinfect high-touch surfaces.
If it is necessary to be in close contact with someone with mpox, wear a mask that covers your mouth and nose and wash your hands frequently with soap and warm water.

Mpox can spread between the time symptoms first appear until the time the rash has fully healed.

If you suspect you have mpox or have been diagnosed with mpox, there are steps you should take to help prevent spreading the disease to others, including all guidance from your local department of health:

If you have an active rash or other symptoms, stay in a separate room or area away from people or pets you live with, when possible.
Isolate at home until all of your skin lesions have scabbed and other symptoms have resolved.
Wear a mask that covers your nose and mouth if you must be around others.

Vaccination to prevent mpox

Vaccination can help prevent mpoxinfection for people who have been in close contact with someone with confirmed or suspected mpox, or who are at high risk for exposure to mpox.

Two vaccines that are licensed by the FDA to prevent smallpox can also be used to prevent mpox infection – JYNNEOS, which is also known as Imvamune or Imvanex, and ACAM2000.

JYNNEOS is currently available through a variety of health centers, community providers, and pharmacies for people who are at high risk for exposure to mpox. Philadelphia residents can call 215-685-5488 or visit the PDPH Mpox vaccine website for more information on how to schedule a vaccine if eligible. ACAM2000 is available, but requires special handling and administration and is not appropriate for many people, including those with certain skin conditions, pregnant people, or people with weakened immune systems. Penn Medicine has an extremely limited supply of vaccine for eligible patients. We are not taking appointment requests for mpox vaccines.

Mpox diagnosis

To diagnose mpox, your healthcare provider will take a swab from a skin lesion and send it to a lab for polymerase chain reaction (PCR) testing which can detect the virus.

Mpox treatment and symptom management

Mpox symptoms typically last from 2 to 4 weeks and most people with mpox get better on their own without treatment. However, there are things you can do to feel better, including:

Drinking plenty of fluids
Resting
Taking a warm oatmeal bath. Soaking an oatmeal bath can provide relief for dry, itchy rashes.
Using over-the-counter pain relievers and fever reducers

Currently, there are no treatments specifically for mpox infection. However, given the similarity between mpox and smallpox viruses, therapies such as antiviral drugs and immune globulin developed to protect against smallpox may be used to treat mpox virus infections, especially for people with severe symptoms.

If you are infected with mpox, talk to your healthcare provider for more information on your eligibility for certain treatments, including the antiviral drug, tecovirimat (TPOXX).

Mpox Treatment and Symptoms Management

Mpox symptoms typically last from 2 to 4 weeks and most people with mpox get better on their own without treatment. However, there are things you can do to feel better, including:

Drinking plenty of fluids
Resting
Taking a warm oatmeal bath. Soaking an oatmeal bath can provide relief for dry, itchy rashes.
Using over-the-counter pain relievers and fever reducers

If you are infected with mpox, talk to your healthcare provider for more information on your eligibility for certain treatments, including the antiviral drug, tecovirimat.