When South African infectious disease specialist Lucille Blumberg checked her email on the morning of May 1, while the country was celebrating the Labor Day holiday, an urgent message caught her attention.

People in protective gear remove waste from the MV Hondius cruise ship after its arrival at the Port of Rotterdam, Netherlands, Monday, May 18, 2026. (Photo: AP)

A U.K.-based colleague had written about a passenger from a cruise ship sailing thousands of miles away in the Atlantic Ocean who had been evacuated and admitted to a Johannesburg hospital with suspected pneumonia. Others aboard the vessel were also sick.

The colleague, who monitors diseases in remote British overseas territories in the South Atlantic Ocean, asked Blumberg to follow up on the passenger, who had been evacuated from the ship in one of the territories, Ascension Island.

Blumberg and other experts at South Africa’s National Institute for Communicable Diseases were suddenly thrown into the race to identify the cause of an outbreak aboard the Dutch cruise ship MV Hondius.

"Even though it was a public holiday, we moved, we moved really fast," Blumberg told The Associated Press. "It was busy. There were many conversations. There were online discussions, and there was laboratory testing happening at the time."

Within 24 hours, they had determined that the man’s illness was caused by hantavirus, a rare rodent-borne virus.