An outbreak of severe respiratory illnesses aboard the MV Hondius, a Dutch flagged cruise ship, was first reported to the WHO on May 2, 2026. As of May 8, WHO has reported a total of eight cases (six confirmed and two probable cases), including three deaths (among two confirmed and one probable case).  All six cases have been confirmed as infected with the Andes virus, a species of hantavirus with documented person‑to‑person transmission following prolonged close contact.  

The MV Hondius departed Argentina on April 1, 2026 and the first case became ill on April 6. The ship traveled to multiple destinations throughout the South Atlantic. According to the WHO, on May 2, 2026 there were 147 passengers and crew on board.  Another 34 persons had previously left the ship.   As of May 10, 2026, the vessel has docked at Tenerife, Spain and safe repatriation of US citizens is being coordinated by the US government, including the State Department, Administration for Strategic Preparedness and Response (ASPR), and CDC.  ​

Andes virus is a hantavirus species endemic to South America and is mainly transmitted through exposure to infected rodent feces and urine. Andes virus is the only species of hantavirus where person‑to‑person transmission has been documented, typically following prolonged and close personal contact. Based on data from prior outbreaks, individuals infected with Andes virus are considered infectious only after the onset of symptoms. 

Hantavirus has an incubation period of 4-42 days. Hantavirus pulmonary syndrome (HPS) or Hantavirus cardiopulmonary syndrome (HCPS) is a severe respiratory illness caused by hantavirus. After a 4-to-6-day prodromal period with flu-like and gastrointestinal symptoms, the patient can progress rapidly to cardiac and respiratory compromise, with a case fatality rate of 30–40%.  

Andes virus is the most frequent cause of HPS in South America and is not endemic to North America. The primary cause of HPS in North America is the Sin Nombre virus, which has not been associated with person-to-person transmission. ​

Returned passengers will receive daily symptom monitoring by public health, and affected LHDs will coordinate with healthcare facilities and EMS in jurisdictions where a returned passenger has been identified if they expect a returned passenger will require medical evaluation.  

Clinicians who are providing medical care for patients who traveled on the MV Hondius and are presenting with signs/symptoms consistent with Andes virus infection should take appropriate infection control precautions (see Recommendations for Healthcare Infection Prevention and Control, below) and notify their hospital’s infection prevention team.  

Testing for Andes virus in a returning cruise ship passenger and/or their close contacts should only be performed in coordination with local health department with CDPH involvement. Testing is not recommended for asymptomatic returned travelers or contacts and should be reserved for those exhibiting symptoms. Providers are reminded that suspect hantavirus cases should be immediately reported to the local health jurisdiction where the patient resides, who can help coordinate appropriate testing and provide additional guidance. 

Individuals with Andes Virus infection showing signs of HPS should be evaluated as soon as possible at a facility with critical care capacity that can provide extra corporeal membrane oxygenation (ECMO). ​

CDC-recommended precautions for healthcare providers treating patients with suspected or confirmed Andes virus infection include:  

• Patient placement in an airborne infection isolation room (AIIR), and  
• Personal protective equipment: gown, gloves, eye protection, N95® respirator or higher 

Healthcare providers and EMS should coordinate with local health departments and CDPH for transport and infection prevention recommendations if any exposed individuals are requiring hospitalization.  ​

Clinical Laboratories handling specimens from patients with suspected hantavirus infection should maintain heightened awareness and ensure strict adherence to biosafety practices, including BSL-2 enhanced practices, containment equipment, and facilities are recommended for laboratory handling of specimens from persons potentially infected with hantaviruses.​​

A diagnostic molecular RT-PCR assay for hantavirus is available at the CDPH Center for Laboratory Sciences (CLS) Viral and Rickettsial Disease Laboratory (VRDL), and serology testing to detect IgM and IgG antibodies against hantavirus is available at CDC. CLS VRDL will facilitate submission of samples to CDC for serology testing. ​

To request testing

Contact VRDL (VRDL.submittal@cdph.ca.gov) and the CDPH hantavirus SME, Mary Beth Danforth (Mary.Danforth@cdph.ca.gov). 

Serum and, if possible, whole blood should be collected for hantavirus serology and PCR. Respiratory swabs should also be collected to rule out other respiratory viruses. Details about specimen collection and shipping can be found at the CLS VRDL Sin Nombre Viru​​s (Hantavirus Pulmonary Syndrome) (PDF) and PCR test page​.

LHDs will be notified by CDPH if any returned passengers or contacts are residing in, or repatriating to, their jurisdiction. 

LHDs with known returned passengers should follow CDC guidance and consult with CDPH regarding activity modification and symptom monitoring, including 42-day daily symptom monitoring from day of departure from ship. 

LHDs with returned passengers or contacts that become symptomatic should immediately notify CDPH by contacting the CDPH Infectious Diseases Branch (510-620-3434) during business hours, or the CDPH Duty Officer (916-328-3605) after hours or on weekends/holidays. If they are requiring hospitalization, CDPH will assist with coordination of transport and treatment at a previously designated healthcare facility with 24-​hour ECMO coverage. Contingency planning if residents require medical transport, care and testing should be made in advance in consultation with CDPH. ​