CDC Issues Alert for Potential Hantavirus Exposure Following Cruise Ship Outbreak

The Centers for Disease Control and Prevention (CDC) is alerting healthcare providers and public health departments to the availability of testing for individuals who may have been exposed to hantavirus, specifically the Andes virus, following an outbreak on a cruise ship. While the risk to the general American public remains very low, the CDC is actively monitoring U.S. passengers from the affected vessel and their close contacts for any potential cases. The agency is providing guidance on diagnosing and managing hantavirus infections, including the rare person-to-person transmissible Andes virus.

An outbreak of Andes virus, a type of hantavirus endemic to South America, was reported to the World Health Organization (WHO) on May 2, 2026, aboard the M/V Hondius cruise ship. By May 6, 2026, the WHO confirmed the cause of the severe respiratory illness cluster among passengers and crew was this particular hantavirus. Andes virus is distinct among hantaviruses for its ability to spread from person to person, though this is uncommon and typically requires prolonged close contact. As of May 15, the WHO reported 10 cases linked to the cruise ship outbreak, with 8 laboratory-confirmed and three resulting in fatalities. While no confirmed cases of Andes virus associated with this specific outbreak have been identified in the United States as of May 18, the CDC is working with state health departments to monitor individuals who traveled on the ship or had close contact with symptomatic passengers who later tested positive.

Hantaviruses can cause serious illnesses in humans, primarily through contact with infected rodents. In the Western Hemisphere, these viruses, known as New World hantaviruses, can lead to Hantavirus Pulmonary Syndrome (HPS), a severe lung illness. The most common hantavirus responsible for HPS in the United States is the Sin Nombre virus, which is not transmitted between people. Outside of the U.S., other hantaviruses, referred to as Old World hantaviruses, can cause Hemorrhagic Fever with Renal Syndrome (HFRS), affecting the kidneys. Seoul virus, which can cause HFRS, is found globally, including in the United States. Hantavirus infections can also manifest as non-specific viral symptoms without respiratory or kidney involvement. Infections typically occur more frequently during warmer months when rodent populations increase and human exposure to rodent-infested environments like cabins, sheds, or homes is more common. The primary vectors for hantaviruses vary; for instance, the deer mouse commonly transmits Sin Nombre virus in the U.S., while the long-tailed pygmy rice rat is associated with Andes virus.

Healthcare providers are advised to consider Andes virus infection in patients presenting with symptoms consistent with hantavirus and who have a connection to the M/V Hondius cruise ship outbreak, either by being aboard or having direct contact with someone affected by the outbreak. Immediate notification of state, tribal, local, or territorial health departments is crucial for reporting suspected cases and arranging diagnostic testing. It is important for clinicians to be aware that specialized Andes virus assays may not detect other New World hantaviruses prevalent in the United States. For patients exhibiting symptoms of HPS or other hantavirus infections without a cruise ship link, but with a history of exposure to rodents or their excreta, testing for other New World hantaviruses should be considered. Similarly, patients with symptoms suggestive of HFRS and a history of rodent exposure should be evaluated for Old World hantaviruses. For any hantavirus testing, including Andes virus, clinicians must consult with the CDC’s Viral Special Pathogens Branch by contacting the CDC Emergency Operations Center at 770-488-7100 and requesting the on-call epidemiologist. Specimens will not be accepted without prior consultation.

Article by Mel Anara, based upon information from the Centers for Disease Control and Prevention.

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