Four California residents who were recently exposed to hantavirus in connection with a deadly outbreak aboard a Dutch cruise ship are being monitored and haven’t showed any symptoms, health officials said Monday.

One of them is a Santa Clara County resident who was a passenger aboard the MV Hondius cruise vessel but disembarked before the outbreak was detected. The resident is at home, feeling well and doesn’t have any symptoms, health officials said Monday. They are under close monitoring and their activities are being restricted, as recommended by the U.S. Centers for Disease Control and Prevention, according to the Santa Clara County Public Health Department.

“I want to reassure the public that the risk of contracting Andes hantavirus in Santa Clara County remains extremely low,” said Dr. Sarah Rudman, Santa Clara County’s public health officer.

The Santa Clara County resident was one of about 150 passengers and crewmembers aboard the small cruise ship, where three people have died from the rare Andes hantavirus strain.

State health officials said Monday that a total of four California residents were exposed to hantavirus in connection with the ship. Three were passengers and another Californian was briefly exposed to an ill passenger returning on an international flight.

All four Californians are currently asymptomatic, said Dr. Erica Pan, California’s public health officer, during a media briefing on Monday.

An ‘unusual outbreak’

The Santa Clara County resident is one of two passengers from California who have returned to the state so far. The other passenger is from Sacramento County and was the person who was exposed to the passenger on a flight.

The other two Californians, whose home counties weren’t released, are currently undergoing evaluation at a secure medical facility in Nebraska.

“We understand public concern about this unusual outbreak,” Pan said. “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.”

The World Health Organization was notified on May 2 of severe respiratory illness among passengers and crew on the ship, according to the CDC. As of Friday, there had been eight cases reported, including the three deaths.

“We understand public concern about this unusual outbreak. … 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.”
Dr. Erica Pan, California Department of Public Health director

The cruise ship had departed from Ushuaia, Argentina, on April 1 and traveled across the South Atlantic Ocean, stopping at several remote locations, including Antarctica, South Georgia Island, Tristan da Cunha, Saint Helena, and Ascension Island. The 147 people aboard included 86 passengers and 61 crew from 23 different countries.

Hantaviruses infect rodents and are occasionally transmitted to humans, health officials said. People usually get infected through contact with infected rodents or their urine, droppings, or saliva.

The Andes hantavirus can cause “limited person-to-person transmission only with close and prolonged contact, particularly among household members or intimate partners,” health officials said.

More information on the cruise ship and hantavirus in general is available from the California Department of Public Health.