An international health crisis unfolded aboard the MV Hondius cruise ship as it remained stationary off the coast of Praia, Cape Verde, on May 5, 2026, grappling with a suspected hantavirus outbreak that has led to three fatalities and multiple infections. Health authorities were in a race to secure a port for the vessel, which had departed Ushuaia, Argentina, on April 1, with passengers and crew now in isolation after Cape Verde denied docking.

The World Health Organization (WHO) confirmed that the MV Hondius would head to Spain's Canary Islands, although Spanish authorities awaited epidemiological data for a final decision on which port would receive it. The immediate priority was the evacuation of two crew members requiring urgent medical care, potentially to the Netherlands, before the ship could proceed. So far, two hantavirus cases have been confirmed, with five other suspected cases among the 147 individuals on board. Of these, one is critically ill, and three have reported mild symptoms, in addition to the three reported deaths.

Hantavirus is generally a rare but potentially deadly disease, primarily transmitted to humans through infected rodents' urine, droppings, or saliva, or through direct contact. However, a critical question arising from this outbreak is the possibility of human-to-human transmission, which has been reported in previous outbreaks involving the Andes virus, a specific hantavirus species circulating in South America. The WHO's working assumption is that the pathogen involved is the Andes virus, with sequencing currently underway in South Africa to confirm its species.

The investigation into the outbreak's origin suggests that the first two people to die, a Dutch couple who joined the ship in Argentina, were likely infected off the vessel. The husband died on board on April 11, and his wife, who suffered from gastrointestinal symptoms, disembarked in Saint Helena to accompany his body. She subsequently deteriorated during a flight to Johannesburg on April 25 and died the following day. This tragic event prompted contact tracing efforts for anyone she may have come into contact with during her flight. The WHO emphasized that human-to-human transmission of hantavirus typically occurs only among very close contacts.

The MV Hondius, an expedition vessel, had passengers making shore excursions to various Atlantic islands for activities like birdwatching. This raises the possibility of an external source of infection from these islands, or that rodents may have entered the ship via cargo, subsequently spreading the disease. Passengers from Britain, Spain, and the United States, along with crew from the Philippines, represented 23 nationalities on board. Currently, a British passenger is in intensive care in Johannesburg, while the two crew members needing urgent care are British and Dutch.

Hantaviruses are broadly categorized into two groups: Old World (found in Europe, Asia, Africa) and New World (found in the Americas). Old World viruses typically have a mortality rate of up to 14%, causing symptoms such as body aches, upset stomach, mild cough, and in rare cases, acute but reversible renal failure. In contrast, New World viruses, particularly those causing Hantavirus Pulmonary Syndrome (HPS) prevalent in the United States, can have a lethality exceeding 40%. HPS manifests with severe respiratory symptoms, including coughing and shortness of breath, progressing to fatigue, fever, muscle aches, headaches, dizziness, nausea, vomiting, and abdominal pain, with a mortality rate of approximately 38%. Hemorrhagic Fever with Renal Syndrome (HFRS), caused by other hantaviruses like the Seoul virus, primarily affects the kidneys, with symptoms including severe headaches, abdominal pain, nausea, blurred vision, low blood pressure, internal bleeding, and acute kidney failure, and a fatality rate between 1% and 15% depending on the specific virus. The exact strain affecting passengers on the MV Hondius is crucial for understanding transmission dynamics, as the Andes virus is unique for its human-to-human spread.

There is currently no specific treatment or cure for hantavirus infections. Medical management focuses on alleviating symptoms, which may involve oxygen therapy, intensive care, respirators, and dialysis, particularly if the lungs or kidneys are severely affected. Early medical intervention is crucial for a better prognosis. While alarming, hantavirus cases remain extremely rare, and the WHO assesses the global risk from this outbreak as low. Individuals who have been in regions where the virus is prevalent and experience flu-like symptoms such as shortness of breath or fever are advised to seek medical attention.