Nine cases of the Andes virus hantavirus infections linked to the cruise ship MV Hondius have been reported, seven of which have been confirmed, the World Health Organization (WHO) said on Monday.

One of the 14 Spanish passengers isolated at Madrid's Gómez Ulla Hospital has tested preliminarily positive on the PCR performed upon arrival, Spanish Health Minister Monica Garcia wrote on X on Monday.

The individual remains asymptomatic and in good general condition, while the other 13 passengers have tested provisionally negative, she added.

In the United States, 18 people are being monitored for hantavirus across two locations: 16 asymptomatic passengers (including one positive case) are at the University of Nebraska, while the other two are at Emory University in Atlanta, where one has shown symptoms, according to CNN. 

Meanwhile, a French passenger, among five French nationals evacuated from the cruise ship, has tested positive for the Andes hantavirus, French Health Minister Stephanie Rist said on Monday.

The woman developed symptoms during the repatriation flight and her condition worsened overnight.

Rist added that 22 close contacts of hantavirus cases had been identified in the country and ordered to isolate.

Meanwhile, 12 employees of the Radboud University Medical Center in the Netherlands have been placed in quarantine for six weeks as a precaution after incorrect procedures were followed while caring for a patient infected with hantavirus.

The blood and the urine drawn from the patient should have been processed and disposed of, respectively, "according to a stricter procedure," the hospital wrote on Monday.

Isolated incident unrelated to cruise outbreak

Health authorities in the state of Minas Gerais in Brazil confirmed the country's first hantavirus-related death of the year on May 12. The victim, a 46-year-old man, died on February 8 this year after showing symptoms since February 2.

Preliminary investigations indicate the man contracted the virus in agricultural and livestock areas through contact with wild rodents. Following his death, local health officials conducted biological testing based on his clinical symptoms, which returned a positive result for hantavirus.

Authorities emphasized that this is an isolated case with no connection to the ongoing health incident aboard the MV Hondius cruise ship.

Andes virus is a rodent-borne hantavirus endemic to South America and the only known hantavirus capable of limited human-to-human transmission.

No licensed specific antiviral treatment or vaccine for hantavirus infection currently exists.