JOHANNESBURG: On the morning of May 1, South African infectious disease expert Lucille Blumberg was checking her email as she celebrated the Labor Day holiday in South Africa when an urgent message caught her eye.A British colleague monitoring disease in a remote British overseas territory in the South Atlantic once wrote about a passenger on a cruise ship thousands of miles away in the Atlantic being evacuated and taken to a Johannesburg hospital with suspected pneumonia. Others on the ship also fell ill. Bloomberg and other experts at South Africa’s National Institute of Communicable Diseases were suddenly thrust into the race to determine the cause of the outbreak on the Dutch cruise ship MV Hondius. Even though it was a holiday, she said, “it was still very busy.” Within 24 hours, they determined the man’s illness was caused by hantavirus, a rare rodent-borne virus. But first, Blumberg and her colleagues had to rule out many other possible infections before narrowing it down to the original cause. First, they thought it might be Legionella, a bacterium that causes severe pneumonia and bird flu. “Legionella has been well described in outbreaks in hotels and on cruise ships, as has certainly been the case with influenza.” All of these tests came back negative. Experts also conducted extensive testing for other respiratory illnesses. Moreover, they are all negative.The team then began paying closer attention to bird watchers, who reportedly visited parts of South America where birds were present but also rodents. That prompted South African disease experts to turn to another theory: a rare rodent-borne hantavirus infection that is found in parts of South America. “This is a well-described virus in Chile and Argentina, but it is uncommon,” Bloomberg said. Hantavirus experts from South America and the United States also received immediate help, with assistance from the United Nations health agency World Health Organization, who were able to arrive via Zoom call. “This is so unusual,” she said.By then, it was already Saturday morning. Bloomberg called the head of the only laboratory in South Africa capable of testing for hantavirus. “I said, we want to do hantavirus, and she said, ‘Yeah, I’ll do it.'” That afternoon, a blood sample from the patient was tested and came back positive for hantavirus. The team conducted a second set of tests to confirm this.
