TEXAS — Health officials are monitoring two Texas residents following their return from a trip on the cruise ship MV Hondius, which experienced an outbreak of hantavirus.

The Texas Department of State Health Services (DSHS) said in a statement that the Centers for Disease Control and Prevention notified them about the two Texas passengers who left the ship and returned to the U.S. before the outbreak was identified.

“Public health workers in Texas have reached the two individuals, and they report they are not experiencing any symptoms and did not have any contact with a sick person while aboard the ship,” the statement said. “They have agreed to monitor themselves for symptoms with daily temperature checks and contact public health officials at any sign of a possible illness.”

DSHS said it will not release any additional details about the passengers to protect their privacy.

The strain of hantavirus found on the cruise ship can spread from person to person in situations of “close or prolonged contact,” according to the World Health Organization (WHO).

The WHO first received a report of the outbreak on May 2 after a group of passengers experienced “severe respiratory illness.” On May 4, the WHO identified seven cases of hantavirus — two laboratory-confirmed cases and five suspected cases, including three people who had died. Authorities in Switzerland then announced another positive hantavirus test on Wednesday for a man who had left the cruise earlier, bringing confirmed active cases to five.

The MV Hondius started its journey on April 1 in Ushuaia, Argentina, and traveled to mainland Antartica, South Georgia, Nightingale Island, Tristan da Cunha, Saint Helena and Ascension Island. The ship carries 147 passengers and crew members.

The first passenger to experience symptoms of the virus fell ill on April 6, and he later died on April 11. The ship is now heading for Spain’s Canary Islands with passengers isolated in their cabins.

Health authorities have identified that it is the Andes virus, the only hantavirus thought to spread human-to-human in limited circumstances. Other hantaviruses usually spread through contact with wild rodent droppings.

According to the WHO, the symptoms of hantavirus include headache, dizziness, chills, fever, myalgia and gastrointestinal problems, and the symptoms usually appear two to four weeks after exposure.

The WHO has said the risk to the global population is low, and the health agency “will continue to monitor the epidemiological situation and update the risk assessment as more information becomes available.”

Public health agencies in Georgia, Arizona and California are also monitoring residents who were aboard the cruise ship and have returned home, according to the New York Times. None have showed symptoms. 

The Associated Press contributed to this reporting.