Hantavirus Outbreak Kills 3 on Atlantic Cruise Ship Off Cape Verde

A hantavirus outbreak on an Atlantic cruise ship anchored off Cape Verde has killed at least three people and prompted warnings from doctors about its high lethality. The Andes strain carries a mortality rate of 35 to 38 percent for certain cases, and early flu-like symptoms increase the chance of misdiagnosis.

"If you think about it from that term, it's pretty terrifying," Dr. Zaid Fadul said Wednesday.

Fadul, speaking to Fox News, said the rodent-borne disease starts with fatigue, chills, muscle aches, headaches and dizziness. It then damages blood vessels and can prove fatal.

"It’s very, very common to be misdiagnosed with the flu early on," he said. Symptoms can worsen over a single day and become overwhelming quickly.

The World Health Organization is investigating. Its website says illness began between April 6 and April 28. Patients first had gastrointestinal problems and fever, then quickly developed pneumonia, acute respiratory distress syndrome and shock.

The WHO said isolation, patient care and medical evacuations are in place to manage the outbreak.

Fadul sought to calm fears of wider spread. "I understand people's concern, anxiety. I will tell you that with the amount of attention and focus and effort being put into containing this, it should keep it contained," he said.

The virus has a long latency period, he added, and people who might be infected should quarantine for up to eight weeks. "At this point, we've identified it. You've quarantined everyone. Those people who are at risk are going to be kept away from the general population and, typically, you have to be in really close contact with somebody... to really pick it up person-to-person... and we've got the appropriate measures in place, and my suspicion is we've hopefully contained this."

Medical experts have told Fox News Digital that rodents usually spread the virus, though contaminated materials or bites can transmit it too.