Mpox (monkeypox) is a viral disease similar to smallpox. It causes fever, swollen lymph nodes, and a lesion-like rash. The lesions can appear on or near your genitals or anus and in other areas.

Mpox is also a zoonotic disease. This means it can be transmitted from animals to humans and vice versa. It can also be transmitted from one human to another.

There are two different types of the mpox virus, the West African virus, and the Congo Basin virus.

Before 2022, most cases of mpox occurred in central and western Africa. However, cases of mpox caused by the West African form of the virus have been reported in 94 countries worldwide as of the time of this article’s publication, including in areas where it doesn’t usually occur.

Read on to learn about the causes, symptoms, and diagnosis of mpox. This article will also explain how mpox spreads and how it can be treated.

The Word Health Organization (WHO) changed the name “monkeypox” to mpox in November 2022 to reduce the risk of stigmatization and other issues. Where possible, this article has been updated to reflect this change.

Mpox is caused by the mpox virus. The virus is part of the Orthopoxvirus genus, which includes the virus that causes smallpox.

Scientists first identified the disease in 1958. There were two outbreaks among monkeys used for research. That’s why the condition is called monkeypox.

The first case of mpox in a human happened in 1970 in the Democratic Republic of the Congo.

The symptoms of mpox are similar to those of smallpox. Mpox symptoms are typically milder.

After you contract the mpox virus, it typically takes 6 to 13 days for symptoms to appear. However, this can range from 5 to 21 days.

The early symptoms can include:

After the fever develops, a rash usually appears 1 to 3 days later. The rash typically affects your:

  • face, which is the most common site
  • palms of your hands
  • soles of your feet
  • mouth
  • genitalia
  • eyes, including the conjunctivae and cornea

A rash may come before or after fever and other flu-like symptoms. Some people may only experience a rash.

The rash associated with mpox consists of lesions that evolve in the following order:

After the lesions dry and scab over, they fall off.

The symptoms of mpox generally last 2 to 4 weeks and go away without treatment.

Here’s what the condition looks like in humans:

Possible complications of mpox include:

An infection in the cornea may lead to vision loss.

In severe cases, the lesions might merge together. This may cause the loss of a large area of skin.

In the past, the mpox virus was mainly active in tropical, rural parts of central and western Africa. Since 1970, it has occurred in the following countries:

  • Benin
  • Cameroon
  • Central African Republic
  • Cote d’Ivoire
  • Democratic Republic of the Congo
  • Gabon
  • Liberia
  • Nigeria
  • Republic of the Congo
  • Sierra Leone
  • South Sudan

Historically, most reported cases of mpox are from rural areas of the Democratic Republic of the Congo.

However, as of August 2022, cases of mpox have been reported in 87 other countries where the virus doesn’t usually occur, with 39,434 total cases reported worldwide.

Additionally, on July 23, 2022, the World Health Organization (WHO) officially declared the mpox outbreak a Public Health Emergency of International Concern.

Mypox spreads through direct contact with the mpox virus through the following substances:

  • blood
  • bodily fluids
  • skin or mucous lesions
  • respiratory droplets, for human-to-human contact

It can also spread through contact with objects, fabrics, or surfaces that contain the mpox virus.

People who are pregnant can also pass the virus to their fetus through the placenta.

According to the Centers for Disease Control and Prevention (CDC), the mpox virus can also be spread through intimate contact, which includes:

  • hugging, massaging, or kissing
  • oral, anal, or vaginal intercourse
  • touching the genitals or anus of a person with the mpox virus
  • prolonged face-to-face contact
  • touching objects during sex that contain the mpox virus, such as bedding, towels, or sex toys

Transmission can also happen through:

  • bites and scratches from animals with a mpox infection
  • eating the meat of an animal with a mpox infection

Scientists are still researching whether monkeypox can be spread by a person who has no symptoms, how it spreads through respiratory secretions, and whether or not it can be spread by contact with other bodily fluids, including vaginal fluids, semen, urine, or feces.

According to the CDC, mpox is rarely fatal. In fact, approximately 99% of people who get the West African version of mpox survive. This is the strain that’s responsible for the current outbreak.

Certain people may be more susceptible to severe illness and complications, including:

  • people with weakened immune systems
  • children under 8 years old
  • people who are pregnant or breastfeeding
  • individuals with a history of eczema

People who experience secondary bacterial infections tend to have worse outcomes.

Compared with the West African form of the virus, the Congo Basin form of mpox is usually more severe, It has a fatality rate of around 10%.

Before 2022, most confirmed cases of mpox in the United States were associated with international travel or contact with animals that had gotten the mpox virus.

However, since May 2022, multiple cases have been identified in countries around the globe where mpox doesn’t usually occur.

As of August 17, 2022, 39,434 cases have been reported worldwide in 94 different countries. This includes 13,517 cases in the United States, with the highest number of cases occurring in:

  • New York
  • California
  • Florida
  • Texas
  • Georgia

On August 4, 2022, mpox was declared a public health emergency in the United States.

There’s currently no treatment for mpox. However, monkeypox is self-limiting, which means it can get better without treatment.

Some medications can be used to control an outbreak and prevent the disease from spreading. They can include:

  • vaccinia vaccine (smallpox vaccine)
  • vaccinia immune globulin
  • antiviral medication (in animals)
  • tecovirimat (TPOXX), an antiviral used to treat smallpox
  • brincidofovir (Tembexa), an antiviral used to treat adult and pediatric smallpox
  • cidofovir, which is typically used to treat eye infections caused by cytomegalovirus but has been used in certain mpox cases

Other treatments focus on managing symptoms using over-the-counter or prescription medications, such as pain relievers, topical creams, and oral antihistamines.

According to the WHO, the smallpox vaccine is approximately 85% effective in preventing the development of mpox. If you received the smallpox vaccine as a child and contract the mpox virus, your symptoms may be mild.

There are two vaccines available that may be used for the prevention of mpox, JYNNEOS and ACAM2000.

The CDC currently recommends vaccination for people who have been exposed to mpox and those who are at an increased risk of contracting the virus.

This includes people who:

  • have been identified by public health officials as a close contact of a person with mpox
  • have had a sexual partner within the past 2 weeks who’s been diagnosed with mpox
  • have had multiple sexual partners within the past 2 weeks in an area where mpox cases have been reported
  • who have a job that exposes them to orthopoxviruses, including mpox

In addition to getting vaccinated, the CDC also recommends washing your hands frequently and avoiding direct contact with people who have mpox or objects that they might’ve used to prevent infection.

If you’ve had close contact with someone who has gotten mpox, the CDC recommends consulting with a healthcare professional to determine whether testing is necessary.

Doctors diagnose mpox using several methods:

  • Lab tests: This involves testing the fluid from lesions or dry scabs. These samples can be checked for the virus using a polymerase chain reaction (PCR) test.
  • Biopsy: A biopsy involves removing a piece of skin tissue and testing it for the virus.

Blood tests aren’t usually recommended. That’s because the mpox virus stays in the blood for a short time. Therefore, it’s not an accurate test for diagnosing mpox.

Mpox is a viral disease and zoonotic condition, which means it can spread from animals to humans. It can also spread through contact between two humans.

The first symptoms typically include fever, muscle aches, and swollen lymph nodes. As the disease progresses, it causes a rash, which can appear on or near your genitals, anus, face, chest, and extremities.

The rash consists of lesions that turn into fluid-filled blisters, which then dry up and fall off. The rash typically starts on your face and then progresses, usually to your arms and legs. However, it can occur in other parts of your body as well.

Getting vaccinated if you’re at risk, washing your hands frequently, and avoiding contact with others who have monkeypox can help prevent infection.