Mpox, formerly known as monkeypox, is an infectious disease caused by the mpox virus, a zoonotic virus that can spread from animals to people. The virus belongs to the Orthopoxvirus genus, the same family as the variola virus responsible for smallpox. While related, mpox is less severe than smallpox. Cases have historically been reported in the tropical rainforest areas of Central and West Africa, but global travel can spread the virus to other regions.
Transmission Methods
The mpox virus is transmitted from animals to humans, between humans, and from contaminated materials. The virus can enter the body through breaks in the skin, which may not be visible, or through mucous membranes in the eyes, nose, or mouth. Transmission can occur through:
- Close, direct contact with an infected person’s rash, scabs, or bodily fluids, which can happen during intimate activities like cuddling, kissing, or sexual contact.
- Prolonged, face-to-face contact via respiratory secretions from an infected person talking or coughing.
- Bites or scratches from an infected animal, such as a rodent or primate, or by handling or preparing the meat of an infected animal.
- Touching contaminated objects and surfaces, such as clothing, bedding, and towels used by someone with an active infection.
Symptoms and Disease Progression
The incubation period, the time from exposure to the onset of symptoms, is 3 to 21 days. The illness begins with flu-like symptoms, and a distinguishing feature from similar illnesses is the swelling of lymph nodes. Initial signs include:
- Fever
- Headache
- Muscle aches and back pain
- Chills
- Exhaustion
A distinctive rash emerges one to four days after the initial symptoms. The rash often begins on the face before spreading to other parts of the body, including the palms of the hands and soles of the feet. The rash may be confined to a few bumps or can be widespread.
The rash progresses through several stages over two to four weeks. It begins as flat, red spots (macules) that become raised bumps (papules). These bumps then turn into fluid-filled blisters (vesicles) and then pus-filled pustules. Finally, the pustules crust over, form scabs, and fall off to reveal new skin.
A person is contagious from the onset of symptoms until all scabs have fallen off and the rash has healed. The illness lasts between two and four weeks. While most cases are mild, complications can include severe pain from the rash, especially if it affects the genital area or mouth, which can interfere with eating and drinking.
Diagnosis and Medical Treatment
Diagnosing an mpox infection involves a clinical assessment and laboratory testing. A healthcare provider will evaluate a patient’s symptoms, travel history, and any potential exposure to the virus. Since the rash can resemble those of other diseases like chickenpox or measles, a definitive diagnosis requires specific tests.
The most reliable method for confirming mpox is a polymerase chain reaction (PCR) test. To perform this test, a healthcare provider swabs a sample from one or more skin lesions. This sample is then sent to a laboratory to detect the genetic material of the mpox virus. While blood tests may be used, PCR testing of a lesion is the primary diagnostic tool.
There is no specific treatment exclusively approved for mpox virus infections. Medical care is primarily supportive, focusing on managing symptoms, preventing dehydration, and addressing any secondary bacterial infections from the skin lesions. Patients are advised to rest and maintain adequate fluid intake.
Because the mpox virus is genetically similar to the smallpox virus, certain antiviral medications developed for smallpox may be used. The antiviral drug tecovirimat (TPOXX) may be recommended for individuals at higher risk of becoming severely ill or who have compromised immune systems. Depending on the severity, some patients may require hospitalization for more intensive care.
Prevention and Vaccination
Preventing mpox infection involves both behavioral changes and vaccination. A primary prevention strategy is to avoid close, skin-to-skin contact with individuals who have a rash that looks like mpox. This includes avoiding direct contact with their rash, scabs, or bodily fluids.
Do not share personal items with someone who has mpox. This includes objects like bedding, towels, eating utensils, and sex toys, as these can become contaminated. Practicing good hand hygiene, such as frequent handwashing with soap and water or using an alcohol-based hand sanitizer, is another measure to reduce the risk of transmission.
Vaccination is an effective prevention tool. Vaccines developed to protect against smallpox have been found to be effective against mpox. The JYNNEOS vaccine is a two-dose vaccine approved for preventing both smallpox and mpox. It is often recommended for people who have been in close contact with someone diagnosed with mpox, a strategy known as post-exposure prophylaxis.
The vaccine is also recommended for individuals who may have a higher risk of being exposed to the virus. Another vaccine, ACAM2000, is also available and provides protection but is associated with a greater potential for side effects. Healthcare providers can help determine who should receive a vaccine based on their individual risk factors and potential exposure.