By Dr. William Kim
Chief Medical Advisor
Beach Cities Health District
May 13, 2026 — Recent news about a Hantavirus outbreak with fatalities has caused concern worldwide. A cruise ship with 86 passengers and 61 crew was reported to have had a cluster of at least 8 individuals who developed an illness known as severe acute respiratory illness (SARI) from which 3 have died. The World Health Organization has determined that the illness was caused by the Andes virus (ANDV), the only hantavirus species known to be able to spread by person-to-person transmission.
Passengers with confirmed infections are being treated in South Africa, Switzerland and the Netherlands. Other evacuated passengers have tested positive for the virus, one in the United States (perhaps a false positive) and France.
In the United States the evacuated passengers are being monitored very carefully at two isolation facilities, one in Nebraska and the other in Atlanta.
Contact tracing has identified contacts, and in cases deemed high risk the CDC and WHO recommend a home or facility quarantine for 42 days.
Interpersonal transmission of ANDV is generally uncommon and when it occurs close prolonged contact is necessary.
For this outbreak, the CDC has defined exposure as being:
- aboard the M/V Hondius from April 6 through disembarkation.
- being within 6 feet of a symptomatic case in an enclosed space for at least 15 minutes.
- having direct personal contact with a symptomatic patient.
- having direct contact with respiratory secretion or other bodily fluids from a symptomatic patient.
For more information, please refer to the CDC: Interim Guidance for Public Health Assessment and Management of People with Potential Exposure to the Andes Virus. (updated May 10, 2026)
Deeper dive into the Hantaviruses:
All medically important Hantaviruses are carried by rodents. There are 22 pathogenic species identified throughout the world and infections are acquired via aerosols of rodent excreta, usually in a closed poorly ventilated building or during cleaning. Rare illnesses have been reported from the scratch or bite of a pet rodent. The only species noted to have human to human transmission is the Andes virus and required close personal contact.
There are two severe febrile illnesses caused by hantaviruses; Hemorrhagic Fever with Renal Syndrome (HFRS) and is caused by hantaviruses of the Old-World viruses, and Hantavirus Cardiopulmonary Syndrome (HCPS) which is caused by hantaviruses of the New World viruses.
Most infections worldwide are of the Old-World viruses and are seen in Asia and Europe of which there are an estimated 26,000 annual human cases. Fewer than 500 New World cases are reported annually, and these occur primarily in South and North America.
In the United States as of December 2022, 864 cases have been identified since surveillance began in 1993 following an outbreak in the Four Corners region of the United States. This outbreak was seen in Arizona, Utah, New Mexico and Colorado and involved previously healthy young adults and carried a mortality of about 80 percent.
Thought rare, human cases of the Old-World illness (HFRS) have been identified in the United States and traced to the Seoul hantavirus which has been found in pet rodents.
The incubation interval between exposure and symptom onset ranges from one to 7 weeks with a median of 14 to 17 days.
Early symptoms of HCPS are generally nonspecific and include a persistent fever, chills, and muscle aches which can be severe. Nausea, vomiting, diarrhea and abdominal pain may occur. Headaches may be prominent. This prodromal phase typically lasts for two to eight days and with those who are noted to not be improving may be followed by the cardiopulmonary phase. This deadly phase is noted to have the abrupt onset of hypotension or low blood pressure and shortness of breath, which is due to noncardiogenic pulmonary edema.
From 1993 to 2023, seventy-nine cases of hantaviral illness have been recorded in California. Of these illnesses, 54 survived and 24 died, with one case having an unknown outcome.
So, from the above reported 30-year period, we can see that the incidence of this illness is quite rare in California and is only caused by direct exposure to rodent excreta and saliva.
