Mpox

🦠 What Is Mpox?

Mpox (formerly known as monkeypox) is a zoonotic viral disease caused by the mpox virus, a member of the Orthopoxvirus genus in the family Poxviridae. This genus also includes the variola virus (which causes smallpox) and vaccinia virus. The virus was first identified in 1958 in laboratory monkeys, hence the original name, though its natural reservoir is believed to be rodents in Central and West Africa. The disease manifests as a self-limiting rash illness that can range from mild to severe, with a case fatality rate historically between 1–10%, depending on the clade and access to healthcare.

🔄 How It Spreads

Mpox transmission occurs through several routes:

• Direct contact with the infectious rash, scabs, or body fluids of an infected person.
• Respiratory droplets during prolonged, face-to-face contact or intimate physical contact.
• Fomites (contaminated objects like bedding or clothing).
• Animal-to-human transmission via bites, scratches, or handling infected animals.
• Vertical transmission from mother to fetus.

The incubation period is typically 6-13 days but can range from 5-21 days. A person is considered infectious from the onset of symptoms until all lesions have crusted over, scabs have fallen off, and a fresh layer of skin has formed.

⚠️ Symptoms & Disease Progression

The illness progresses in stages:

1. Prodromal Phase (0-5 days): Initial symptoms include fever, headache, muscle aches, backache, swollen lymph nodes (lymphadenopathy), and exhaustion. This phase is often followed by the rash.
2. Rash Phase: The rash typically begins on the face and spreads to other parts of the body, including the palms of the hands and soles of the feet. It evolves through stages: macules (flat lesions) → papules (raised bumps) → vesicles (fluid-filled blisters) → pustules (pus-filled lesions) → scabs. The number of lesions can vary from a few to thousands.
3. Complications: Can include secondary bacterial infections, pneumonia, sepsis, encephalitis, and corneal infection leading to vision loss. Severe cases are more common in children, pregnant women, and immunocompromised individuals.

🌍 Global Distribution & Epidemiology

Historically, mpox was endemic in Central and West Africa, with two distinct clades: the Congo Basin clade (more severe, higher fatality) and the West African clade (less severe). In 2022, a global outbreak occurred, primarily driven by the West African clade, spreading to over 100 non-endemic countries, with a significant number of cases among men who have sex with men (MSM). This highlighted new patterns of transmission through close, often intimate, contact networks.

🔬 Diagnosis

Diagnosis is confirmed through laboratory testing:

• Polymerase Chain Reaction (PCR) testing of lesion material (swab from the rash) is the gold standard for detecting mpox virus DNA.
• Viral culture can be performed in specialized labs.
• Serology (testing for antibodies) can support diagnosis but may cross-react with other orthopoxviruses.

💊 Treatment & Prevention

• Treatment: Most cases are self-limiting and require only supportive care (pain management, hydration, treatment of secondary infections). For severe cases or high-risk patients, antiviral drugs like tecovirimat (TPOXX) may be used under investigational protocols.
• Prevention:
  • Vaccination: The JYNNEOS vaccine (a non-replicating vaccinia virus vaccine) is approved for prevention. The older ACAM2000 vaccine (a live vaccinia virus) is also available but has more side effects.
  • Infection Control: Isolation of infected individuals, use of personal protective equipment (PPE) by caregivers, and thorough hand hygiene.
  • Public Health Measures: Contact tracing, risk communication, and avoiding contact with potentially infected animals or materials.

📊 High-Risk Groups

Individuals at higher risk for severe mpox include:

• Children (especially under 8 years old).
• Pregnant or breastfeeding women.
• Immunocompromised individuals (e.g., those with HIV/AIDS, undergoing chemotherapy).
• People with certain skin conditions like eczema.
• Healthcare workers and household contacts of infected individuals due to exposure risk.