A second Spanish citizen from the cruise ship MV Hondius has been confirmed to have contracted hantavirus, Spain’s Ministry of Health said, according to CNN.

The infected individual was among 14 Spanish passengers evacuated from the vessel and placed in quarantine at the Gómez Ulla military hospital in Madrid on May 10. After testing positive, the patient was transferred to a high-level isolation unit, where doctors continue to monitor his condition. Authorities said he had previously been identified as a close contact during the epidemiological investigation of the outbreak on board.

The first hantavirus case involving a Spanish passenger from the MV Hondius was confirmed by the Health Ministry on May 12.

International health authorities are continuing to investigate the outbreak after three passengers died shortly after the ship departed from Argentina in April. Some passengers disembarked on Saint Helena, while others left the vessel in the Canary Islands and returned to their home countries.

According to the World Health Organization, hantavirus is usually transmitted from rodents to humans, although human-to-human transmission may have occurred on board the ship. The incubation period can last up to six weeks, so passengers will remain under observation for 42 days after disembarkation. The virus causes flu-like symptoms but, in severe cases, can lead to damage to the lungs, kidneys, and heart, and may be fatal.