Maricopa County reports new hantavirus case as health officials trace exposures across Valley locations

Maricopa County health officials reported a new hantavirus case in the Valley this week, prompting an investigation into potential exposures at multiple locations. According to the Maricopa County Department of Public Health, the case is part of ongoing efforts to trace contacts and prevent further spread amid recent hantavirus activity in Arizona.

The Maricopa County Department of Public Health is leading the investigation into the newly reported hantavirus case, focusing on tracing potential exposures across several Valley locations, officials said. The department is working to identify individuals who may have come into contact with the infected person or contaminated environments to prevent further spread, according to county health sources.

The Arizona Department of Health Services (ADHS) reported 11 confirmed hantavirus cases in 2024, following six cases in 2023.

Hantavirus infections in Arizona have fluctuated over recent years, with the Arizona Department of Health Services (ADHS) reporting 11 confirmed cases in 2024, following six cases in 2023. The state recorded seven confirmed cases in 2025, including four deaths, with most of those cases concentrated in northern Arizona counties such as Apache and Coconino, ADHS data show. Maricopa County, which includes the Phoenix metropolitan area, has historically reported fewer cases; a University of Arizona summary noted only one confirmed hantavirus case in the county from 2016 to 2022.

The current case in Maricopa County underscores the ongoing risk posed by hantavirus in the region. The virus is carried by certain rodents, including deer mice and cotton rats, which can be present in residential and desert-edge settings throughout the county. According to county health guidance, infection typically occurs when rodent urine, droppings, or nesting materials are disturbed and aerosolized during cleaning or other activities, allowing the virus to be inhaled. Transmission can also happen when contaminated materials are touched and then the face is touched, though human-to-human transmission is extremely rare.

Symptoms of hantavirus infection usually appear one to two weeks after exposure but can take up to eight weeks in some cases, the Maricopa County Department of Public Health said. Early signs include fever, fatigue, muscle aches, headaches, dizziness, chills, and abdominal issues. In severe cases, the illness can progress to Hantavirus Pulmonary Syndrome (HPS), a rare but life-threatening condition characterized by low blood pressure, acute shock, and kidney failure. There is no vaccine or specific treatment for HPS, and recovery can take weeks to months, according to county officials.

ADHS has been actively monitoring hantavirus activity statewide. In May 2026, the agency reported no detected cases of the Sin Nombre virus, one of the hantaviruses known to cause HPS in North America. The department also recently monitored a passenger linked to a hantavirus-related event on a cruise ship, demonstrating ongoing surveillance efforts in real time, according to reports from FOX 10 Phoenix and AZFamily.

Previous Arizona hantavirus cases have been documented in peer-reviewed studies. One report detailed two deaths linked to a common exposure source in Arizona, with genetic analysis confirming closely related hantavirus strains in both cases. Another 2023 case study described a patient who rapidly deteriorated and died shortly after hospital admission, highlighting the difficulty of early diagnosis given symptoms that can mimic other illnesses such as pneumonia or chemical exposure.

Maricopa County public health officials advise residents to take precautions to avoid rodent exposure, including sealing holes and gaps in buildings to prevent rodent entry, using traps safely, and following recommended cleanup procedures. They warn against sweeping or vacuuming dry rodent droppings or nests, as this can aerosolize virus particles. Early medical evaluation is recommended for anyone who develops symptoms consistent with hantavirus after potential rodent contact, since prompt diagnosis and intensive care can improve outcomes.

The Maricopa County Department of Public Health continues to work with local and state agencies to investigate the new case and trace possible exposures in the Valley. The investigation aims to identify locations where the infected individual may have encountered rodents or contaminated environments, as part of broader efforts to monitor and control hantavirus risk in the region.