ATLANTA — The United States has confirmed a fourth case of clade I mpox, with the New York State Department of Health reporting the latest infection in February, health officials announced.
The first U.S. case of clade I mpox was detected in November 2024, followed by cases in Georgia in January 2025 and New Hampshire earlier this month. No additional cases have been reported, and health officials say the infections are not linked.
All four individuals had recently traveled from regions experiencing clade I mpox outbreaks and sought medical care for symptoms after arriving in the U.S., according to the Centers for Disease Control and Prevention (CDC).
The CDC continues to assess the risk of clade I mpox, which is spreading in Central and Eastern Africa, but has not issued any new health alerts.
Mpox, formerly known as monkeypox, is a viral infection that has gained global attention in recent years. While most cases are mild, certain strains, including the more severe clade I variant, have raised concerns among health officials.
Symptoms of Mpox
Mpox symptoms typically appear within three weeks of exposure and can last two to four weeks. According to the Centers for Disease Control and Prevention (CDC), early symptoms may include:
- Fever
- Chills
- Headache
- Muscle aches
- Swollen lymph nodes
- Fatigue
Within a few days of these initial symptoms, a rash develops, often starting on the face or extremities before spreading. The rash progresses through several stages, including fluid-filled blisters, before forming scabs and healing. The lesions can be painful and may leave scars.
Risk Factors and Transmission
Mpox spreads primarily through close, prolonged contact with an infected person, including direct skin-to-skin contact, respiratory droplets, or contaminated objects such as bedding or clothing. The virus can also be transmitted from animals to humans.
The risk of severe illness is higher for individuals with weakened immune systems, pregnant individuals, young children, and those with certain skin conditions. Clade I mpox, which has been spreading in parts of Central and Eastern Africa, is considered more virulent than the clade II strain that caused a global outbreak in 2022.
Treatment and Prevention
There is no specific cure for mpox, but treatment focuses on symptom management. Antiviral medications such as tecovirimat (TPOXX) may be prescribed for severe cases or individuals at high risk of complications. Pain relievers, hydration, and rest are commonly recommended for recovery.
The JYNNEOS vaccine, originally developed for smallpox, has been approved for mpox prevention. It is recommended for individuals at higher risk, including those with known exposure to the virus.
Health officials continue to monitor mpox cases globally, urging individuals with symptoms to seek medical attention and practice preventive measures, such as avoiding close contact with infected individuals and maintaining good hygiene.