Mpox, formerly known as monkeypox, is a viral illness caused by the monkeypox virus. This virus is zoonotic, meaning it can transmit from animals to humans. It also has the capability to spread from person to person. Understanding how mpox spreads is crucial for prevention and control.
Modes of Transmission: How Monkeypox Spreads
The monkeypox virus can be transmitted through several routes, bridging both animal-to-human and human-to-human contact. There are two main clades of the virus, clade 1 and clade 2 (also known as clade I and clade II). Clade 1, primarily found in Central Africa, is associated with more severe illness and higher mortality rates, and may be more easily transmitted. Clade 2, common in West Africa, generally causes less severe disease. Both clades can spread globally, often linked to international travel or animal trade.
Animal to Human Transmission
In natural settings, mpox can spread from animals to humans. This typically occurs through:
- Animal Bites or Scratches: Direct physical injuries from infected animals can introduce the virus.
- Direct Contact with Animal Fluids or Lesions: Handling or coming into contact with the blood, bodily fluids, or lesions of an infected animal can lead to transmission.
- Bushmeat Consumption: In regions where mpox is prevalent, handling and consuming improperly cooked meat from infected animals poses a risk. This includes activities like hunting, trapping, skinning, and cooking potentially infected animals.
Rodents and non-human primates are known animal hosts for the monkeypox virus. While pets like cats and dogs haven’t been confirmed to get sick from mpox, there’s a potential risk of transmission from infected humans to pets through close contact.
Human to Human Transmission
Mpox can also spread effectively between people through various forms of close contact:
- Direct Contact with Rash and Body Fluids: The most common route of human-to-human transmission is through direct contact with the mpox rash, scabs, or bodily fluids of an infected individual. This can happen through touching the lesions or contaminated materials.
- Close, Face-to-Face Contact and Respiratory Droplets: Prolonged face-to-face contact can spread the virus via respiratory droplets, especially during close interactions like talking, coughing, or sneezing. This is also relevant in intimate activities and sexual contact.
- Contact with Contaminated Materials (Fomites): The virus can survive on surfaces and materials. Contact with items such as clothing, bedding, towels, or other objects that have been contaminated with the virus from an infected person can lead to transmission.
- Mother to Fetus Transmission: Pregnant individuals with mpox can transmit the virus to their unborn child via the placenta.
Risk Factors for Monkeypox Transmission
Certain behaviors and situations increase the risk of mpox transmission:
- Close contact with infected individuals: Living with or caring for someone with mpox significantly increases exposure risk.
- Sexual contact: Intimate and sexual contact are recognized modes of transmission.
- Healthcare workers: Medical professionals treating mpox patients are at risk if proper protective measures are not followed.
- Laboratory workers: Individuals handling samples containing the monkeypox virus are at risk.
- Travel to endemic regions: Traveling to areas in Central and West Africa where mpox is more common increases the risk of exposure.
- Contact with potentially infected animals: Hunters, animal handlers, and those in contact with wild animals in endemic regions face higher risks.
Prevention Strategies: How to Avoid Getting Monkeypox
Preventing mpox involves reducing exposure to the virus through several key strategies:
Vaccination
Vaccination is a significant preventative measure against mpox. The Jynneos vaccine is approved for adults 18 and older at risk of mpox exposure. It requires two doses, four weeks apart, for full protection. Vaccination is recommended for:
- Individuals with known or suspected exposure to mpox.
- People who have had a sexual partner diagnosed with mpox recently.
- Men who have sex with men, especially those with multiple partners or new STIs.
- Laboratory and healthcare workers at high risk of exposure.
Vaccination after exposure can also lessen the severity of the illness.
Avoid Contact
Reducing contact with potential sources of the virus is crucial:
- Avoid close contact with people exhibiting mpox-like rashes.
- Limit contact with wild animals, especially in endemic areas.
- If caring for someone with mpox, minimize contact with contaminated items.
Hygiene
Practicing good hygiene is essential in preventing the spread of mpox:
- Frequent handwashing: Wash hands thoroughly with soap and water, especially after contact with potentially infected individuals or animals.
- Use hand sanitizer: When soap and water are unavailable, use an alcohol-based hand sanitizer with at least 60% alcohol.
Symptoms of Monkeypox
Mpox symptoms typically appear within three weeks of exposure. Initial symptoms are often flu-like and may include:
- Fever and chills
- Headache
- Muscle aches and backache
- Swollen lymph nodes
- Fatigue
- Sore throat, cough, or nasal congestion
One to four days after the onset of flu-like symptoms, a distinctive rash usually develops. This rash can appear anywhere on the body, including the face, hands, feet, genitals, mouth, or throat. The rash progresses through stages: from flat spots (macules) to small bumps (papules), blisters filled with clear fluid (vesicles), blisters filled with pus (pustules), and finally scabs before resolving over 2-4 weeks. Individuals are contagious from the onset of symptoms until all scabs have fallen off and new skin has formed.
Diagnosis and Treatment
Mpox diagnosis is made by a healthcare professional. They will evaluate symptoms, examine the rash, and may collect samples from the rash for laboratory testing. Treatment for most mpox cases focuses on alleviating symptoms. This may include pain management and preventing secondary skin infections. Antiviral medications may be considered for individuals at high risk of severe illness. Isolation at home is recommended until the rash has fully healed to prevent further transmission.
Mpox in the U.S.
Mpox is considered rare in the United States, and while it does not spread as easily as some other viruses, vigilance is important. If you develop a new rash or experience mpox symptoms, it is important to contact your healthcare provider. Taking preventative measures, especially if you are at higher risk of exposure, is crucial to minimizing the risk of infection.
With Pritish K. Tosh, M.D.
References
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