Urgent Discovery of Hantavirus in South Africa

JOHANNESBURG — On May 1, while South Africa observed Labor Day, infectious disease expert Lucille Blumberg checked her email. An urgent note from a colleague in the U.K. grabbed her attention. It detailed a passenger from a distant cruise ship who had been evacuated and hospitalized in Johannesburg due to suspected pneumonia. Other passengers on the ship were also unwell.

The correspondent, who tracks illnesses in remote British territories, requested Blumberg’s assistance in investigating this case linked to the cruise ship from Ascension Island. This marked the beginning of a swift response from Blumberg and her team at South Africa’s National Institute for Communicable Diseases to pinpoint the outbreak’s cause aboard the Dutch cruise ship MV Hondius.

“Even though it was a holiday, we jumped into action quickly,” Blumberg recalled. “It was hectic, filled with discussions, online meetings, and lab tests.” Within a day, they identified that the man’s illness stemmed from hantavirus, a rare virus carried by rodents. He is getting better, but unfortunately, three other passengers have passed away, and more have reported symptoms.

Identifying the Cause of the Outbreak

The elderly British man arrived at a Johannesburg hospital with severe illness days prior to his evacuation. Alarmingly, two Dutch passengers aboard the MV Hondius had already died without raising much concern initially. Authorities on Ascension Island had informed the World Health Organization about a cluster of pneumonia-like illnesses on the ship.

Initially, Blumberg’s team suspected it might be Legionella, known for causing severe pneumonia. They also considered the possibility of bird flu.

“I consulted with my infectious disease colleagues, and we discussed typical scenarios,” Blumberg mentioned. “Legionella is commonly seen during outbreaks in hotels and cruise ships, and flu is certainly a concern. These individuals had traveled to areas known for avian influenza.”

However, all tests for those pathogens returned negative. The experts conducted an extensive series of tests for other respiratory diseases, and again, found nothing.

The team began focusing on the ship’s origin—Argentina—and noted that passengers were enthusiastic bird watchers who might have encountered rodents during their travels. This led to a new hypothesis about the hantavirus, commonly found in parts of South America.

Collaboration Across Borders

With this direction in mind, South African experts worked alongside specialists from South America and the U.S., thanks to the facilitation of the WHO. “We could easily set up a Zoom meeting to discuss and get insights. It’s not an everyday occurrence, so that was quite remarkable,” Blumberg noted.

On Saturday morning, Blumberg reached out to the only lab in South Africa capable of conducting hantavirus tests. “I said we needed to run a test for hantavirus, and she quickly agreed to come in.”

Tests on blood samples from the sick man confirmed the presence of hantavirus later that day. A follow-up test was then conducted to ensure accuracy.

A Significant Breakthrough

The positive results, which also identified the Andes strain of hantavirus, allowed the WHO to inform the cruise ship of the outbreak. While hantavirus is generally not easily transmitted between humans, the Andes virus can be spread in this way.

This prompted Blumberg to collect blood samples from a Dutch woman who was one of the initial victims, having disembarked with her husband’s body on St. Helena before being flown to South Africa, where she ultimately passed away.

A posthumous test on her confirmed hantavirus as well.

“It was quite a revelation,” Blumberg noted. “Once you know what you’re dealing with, it certainly helps in the response.” The British man who was the first confirmed hantavirus case from the cruise ship is reportedly on the mend in the hospital. Meanwhile, the ship has arrived in Rotterdam, where it underwent disinfection, and the remaining crew members disembarked.

“I’ve been involved in outbreak responses for 25 years; it’s our daily job. Immediate attention to a pressing issue was crucial, and then we built on that.”