California monitors four exposed to Andes hantavirus
Officials say risk to the public remains extremely low
– The California Department of Public Health confirmed that four California residents are being monitored following potential exposure to Andes hantavirus connected to an outbreak aboard the cruise ship MV Hondius.
State health officials said three of the Californians were aboard the Dutch cruise ship during the outbreak, while a fourth resident was exposed during an international flight after sitting near an infected passenger returning from the cruise.
Officials said the risk to the public remains extremely low.
Two California residents have returned home and are being monitored by local public health officials. Two additional Californians who were aboard the cruise ship were transported by federal authorities to a secure medical facility in Nebraska for further health assessments before returning to California.
On May 8, state health officials announced that one California resident had returned home and was under monitoring. Officials later identified another California resident for active monitoring after potential exposure to a confirmed case during a shared flight.
“We understand public concern about this unusual outbreak,” said Dr. Erica Pan, state public health officer and director of the California Department of Public Health. “Decades of experience in South America have shown that this Andes hantavirus rarely spreads between people. We continue to work with federal and local officials to monitor the health of potentially exposed individuals and prepare for our Californians to come home.”
Officials said local public health agencies are conducting daily temperature checks and monitoring for symptoms consistent with hantavirus infection. Individuals under monitoring have also been directed to modify activities as needed.
The California Department of Public Health said its Viral and Rickettsial Disease Laboratory was previously the only public health laboratory in the United States with a validated hantavirus PCR testing assay. Officials said the laboratory is also providing technical assistance to other laboratories across the country.
State officials said they are coordinating with hospitals and have issued health advisories to clinicians regarding the outbreak and appropriate patient care.
Hantavirus spreads through the urine, droppings, and saliva of wild rodents. Officials said the Andes hantavirus strain connected to the outbreak is found in southern regions of Argentina and Chile and has been associated with rare human-to-human transmission after close, prolonged contact with infected individuals.
Officials noted that Andes hantavirus differs from the Sin Nombre hantavirus found in California and North America, which has not been associated with person-to-person transmission.
From 1980 through 2025, 99 California residents were diagnosed with Sin Nombre hantavirus infection, according to state health officials.
Hantavirus Pulmonary Syndrome is a rare respiratory illness that can progress rapidly to severe respiratory distress. State officials said symptoms may initially resemble influenza and include gastrointestinal illness. Officials said the fatality rate is approximately 30% to 40% and that there is no antiviral treatment for the disease.
More information on hantavirus is available on CDPH’s hantavirus web page and from the CDC’s hantavirus web page. An update on the federal government evacuation and repatriation efforts was issued in a CDC health alert on Friday, May 8.
