In brief
California's health officials confirm the first US case of a new mpox strain, connected to ongoing outbreaks in Africa
The California Department of Public Health (CDPH) has confirmed the first case of a new strain of mpox, previously known as monkeypox, in the United States. This newly identified case belongs to the Clade I strain, distinct from the Clade II variant that has been circulating domestically since 2022. The affected individual recently traveled to Africa and is currently in isolation at home. The CDPH indicated this case is linked to the ongoing Clade I mpox outbreak reported in Central and Eastern Africa. Earlier in the year, the World Health Organization (WHO) classified mpox as a global health emergency. Historically, Clade I has been associated with more severe illness compared to Clade II; however, health officials noted that recent infections with the Clade I strain might not present the same level of clinical severity as previous outbreaks encountered. Mpox, caused by a virus related to smallpox, typically results in milder symptoms, though it is capable of severe cases under certain conditions. Its transmission has shifted from a primary focus on animals to also include human-to-human spread. Initial symptoms of mpox include fever, headache, body aches, and swollen lymph nodes, often accompanied by a rash that can be intensely itchy or painful. The infection generally resolves within two to three weeks; however, it can have fatal outcomes for more vulnerable populations, particularly young children. Mpox is most prevalent in remote regions of West and Central Africa, particularly in countries like the Democratic Republic of Congo. An outbreak earlier this year in the DR Congo resulted in hundreds of fatalities, and the disease has since extended into additional regions of Africa. Effective control of outbreaks is achievable through vaccination, albeit these vaccines are typically limited to individuals at heightened risk or those in close contact with infected persons.
