A new strain of mpox, known as Clade I, has emerged in California’s Central Valley, prompting health officials to investigate its potential spread in the US.
In Stanislaus County, there have been four reported cases of this strain, which historically has been linked to international travel, raising alarms about possible community transmission.
The California Department of Public Health has identified two of these cases as Clade I, with ongoing testing to confirm whether the remaining two cases are of the same strain, according to local health officials.
Interestingly, three of the individuals didn’t report any recent international travel, while officials are still looking into the travel history of the fourth person.
This situation emerges as health authorities are closely monitoring a potential change in the virus’s transmission pattern across the country. Previously, Clade I infections in the US were mostly related to international travel, but since August 2026, there’s been a noticeable rise in cases among those without recent overseas travel.
This trend might indicate that the virus is now spreading within local communities, though how the Stanislaus County patients contracted it remains unclear.
Despite the situation, Dr. Thea Papasozomenos, the public health officer for Stanislaus County, has reassured the public that the overall risk remains low. “While we have identified four cases in our county, we want residents to know that the risk to the general public remains low,” she stated. It’s essential for people to recognize symptoms, get vaccinated if they might be exposed, and seek medical attention when necessary.
Mpox, previously referred to as monkeypox, can cause painful sores and a variety of flu-like symptoms, including fever, chills, swollen lymph nodes, headaches, and muscle aches.
Some patients may have just a few lesions and may not experience noticeable symptoms, which can make it harder to identify infections. Symptoms can show up as late as 21 days after exposure, but most individuals recover in two to four weeks, though complications can occur.
There are two strains of the virus: Clade I and Clade II. Both spread through similar forms of close contact, mainly via direct skin-to-skin interactions, including sexual contact, as well as through exposure to infected sores or bodily fluids.
Transmission can also occur through sharing contaminated clothing, towels, or bedding. However, health officials have noted that the virus doesn’t easily spread through casual encounters, such as passing someone in a store or sharing an office space.
Authorities are recommending that individuals at higher risk of exposure get vaccinated with JYNNEOS, a two-dose vaccine given about four weeks apart. Those who have received their first dose are encouraged to complete the series for better protection.
If someone develops unexplained sores or a suspicious rash, they should reach out to a healthcare provider for testing, which usually involves swabbing the affected area.
Anyone who suspects they have mpox is advised to refrain from close physical contact and sharing personal items until they can get medical advice.
Stanislaus County health officials are collaborating with the California Department of Public Health and healthcare providers to track the infections and reduce the risk of further cases.
