Arizona Officials Confirm First Case of Rare Virus Strain

Arizona Department of Health Services began monitoring individuals after being notified this month of a confirmed travel-related Clade I mpox case in an Arizona resident.

Juliette Fairley

Published: 7/24/2026, 2:40:58 PM EDT

Arizona Officials Confirm First Case of Rare Virus Strain — An undated colorized transmission electron micrograph of mpox virus particles (pink) found within an infected cell (yellow), cultured in the laboratory, captured at the National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility (IRF) in Fort Detrick, Md. (NIAID/Handout via Reuters)

The Arizona Department of Health Services (ADHS) is actively contact-tracing to prevent any potential community spread of Clade I mpox.

ADHS began monitoring individuals after being notified this month of a confirmed travel-related Clade I mpox case in an Arizona resident.

The mpox case marks the state's first-ever confirmed detection of Clade 1.

“ADHS and local public health officials are working to prevent additional infections through monitoring and follow-ups with people who may have been exposed,” health officials said in a statement. “There is currently no evidence of local transmission connected to this case.”

Clade I is considered rare because it is typically only found in parts of Africa and is less common in the United States than the Clade II strain that has been circulating nationwide since 2022.

The ADHS issued an alert to healthcare providers regarding an increase in mpox cases this summer.

As of July 21, 2026, the state has documented a total of 34 mpox cases so far this year. Officials note that public risk remains low because casual contact is unlikely to spread mpox.

UC Davis describes Clade II as milder than Clade I strains, which have historically caused more severe illness and higher mortality rates.

Symptoms for both I and II include rash, fever, sore throat, headache, muscle aches, back pain, low energy, and swollen lymph nodes.

Mpox is transmitted through close person-to-person contact, according to UC Davis Children’s Hospital chief of pediatric infectious diseases Dean Blumberg.

“This can be through talking or breathing close to one another, touching or sex and through sharing contaminated materials such as clothing or bedding,” Blumberg said in a statement. “Pregnant people can transmit the virus to their fetus. People can also contract it from infected animals, either by being scratched or bitten, or by eating meat from an infected animal.”

The U.S. Centers for Disease Control and Prevention (CDC) advocates for preventing Monkeypox with a two-dose JYNNEOS vaccine, which is effective against both Clade I and Clade II.

Vaccination is recommended after exposure when administered within 4 days of infection, though it can still help reduce severe illness up to 14 days after exposure.

“CDC has determined that ongoing human-to-human transmission of clade I MPXV that originated in Central and East Africa meets the criteria to be considered an outbreak and is issuing recommendations for vaccine use among travelers at increased risk of monkeypox exposure who are planning to travel to those specific countries,” CDC officials said in an advisory.