The World Health Organisation is monitoring a cluster of severe respiratory illness linked to a cruise ship currently moored off the coast of Cabo Verde, after confirmed cases of hantavirus resulted in multiple deaths.
According to WHO, seven cases have been identified as of May 4, including two laboratory-confirmed hantavirus infections and five suspected cases. Three people have died, one person remains critically ill in intensive care, and three others are experiencing milder symptoms.
The vessel, which departed Ushuaia on April 1, carried 147 people including 88 passengers and 59 crew members from 23 different nationalities. Its itinerary included stops in remote areas such as Antarctica, South Georgia, Tristan da Cunha, Saint Helena, and Ascension Island.
WHO said the illnesses began between April 6 and April 28 and were characterized by fever, gastrointestinal symptoms, pneumonia, acute respiratory distress syndrome, and shock.
Among the confirmed cases are:
Case 1: An adult male developed symptoms of fever, headache, and mild diarrhoea on 6 April 2026 while on board the ship. By 11 April, the case developed respiratory distress and died on board on the same day. No microbiological tests were performed. The body of the passenger was removed from the vessel to Saint Helena (a British Overseas Territory) on 24 April.
Case 2: An adult female, who was a close contact of case 1, went ashore at Saint Helena on 24 April 2026 with gastrointestinal symptoms. She subsequently deteriorated during a flight to Johannesburg, South Africa, on 25 April. She later died upon arrival at the emergency department on 26 April. On 4 May, the case was subsequently confirmed by PCR with hantavirus infection. Contact tracing for passengers on the flight has been initiated.
Cases 1 and 2, had travelled in South America, including Argentina, before they boarded the cruise ship on 1 April 2026.
Case 3: An adult male presented to the ship’s doctor on 24 April 2026 with febrile illness, shortness of breath and signs of pneumonia. On 26 April, his condition worsened. He was medically evacuated from Ascension to South Africa on 27 April, where he is currently hospitalised in an Intensive Care Unit (ICU). Laboratory testing on an extensive respiratory pathogen panel was negative; however, polymerase chain reaction (PCR) testing confirmed hantavirus infection on 2 May 2026. Serology, sequencing and metagenomics are ongoing.
Case 4: An adult female, with presentation of pneumonia, died on 2 May 2026. The onset of symptoms was on 28 April, with fever and a general feeling of being unwell.
The remaining three are suspected cases that have reported high fever and/or gastrointestinal symptoms and remain on board. Medical teams in Cabo Verde are evaluating the patients and collecting additional specimens for testing.
Health officials are continuing investigations to determine the source of exposure, including possible contact with wildlife during the voyage or prior travel in South America.
Hantavirus is a rare but potentially deadly disease primarily spread through contact with infected rodents or contaminated surfaces.
In the Americas, certain strains have been associated with severe respiratory illness known as Hantavirus Pulmonary Syndrome.
“Hantavirus infections are associated with a case fatality rate of <1–15% in Asia and Europe and up to 50% in the Americas. While there are no specific treatment nor vaccines for hantavirus infections, early supportive care and immediate referral to a facility with a complete ICU can improve survival”, WHO said.
Although person-to-person transmission is considered rare, WHO noted that limited human transmission has been documented previously with the Andes virus strain in South America.
The outbreak response includes international coordination, medical evacuations, laboratory testing, isolation protocols, and contact tracing efforts.
Despite the seriousness of the cases, WHO currently assesses the overall risk to the global population as low and says it will continue monitoring the situation as more information becomes available.