The World Health Organization said it is possible there was human-to-human transmission of hantavirus on a cruise ship in the Atlantic Ocean, a rare way the virus typically carried by rodents can spread.
“We do believe that there may be some human-to-human transmission that’s happening among the really close contacts,” Maria Van Kerkhove , the WHO’s director for epidemic and pandemic preparedness and prevention, said Tuesday.
“We don’t have a full picture yet,” she said, “but we have some working assumptions.”
A suspected hantavirus outbreak aboard a ship carrying 147 passengers and crew has led to three deaths and four other infections, according to the WHO. Two of the seven total cases have been confirmed in laboratories as hantavirus, and the five others were suspected cases, the WHO said.
The passenger-cruise ship called MV Hondius was traveling in the Atlantic Ocean, said the vessel’s operator Oceanwide Expeditions, and is currently off the coast of the West African nation of Cape Verde. The ship wasn’t permitted to dock in Praia, the capital of Cape Verde, due to public health concerns, according to a statement from Cape Verde’s health authority.
Officials are preparing to evacuate two sick people on board to the Netherlands, Van Kerkhove said. After they are evacuated, the ship will go to the Canary Islands, where Spanish authorities will welcome the vessel and work with the WHO to do a full epidemiological investigation, Van Kerkhove said. Oceanwide Expeditions said Tuesday sailing to the Canary Islands would take three days.
Hantavirus, a family of viruses carried by rodents and spread to humans through contact with infected urine, droppings or saliva, doesn’t typically spread between humans. But one strain of the virus found primarily in Chile and Argentina, known as the Andes virus, has shown limited evidence of human-to-human transmission.
While epidemiological assessments and testing are still under way, Van Kerkhove said the WHO is operating under the assumption that this hantavirus is the Andes variant. A Dutch man who died on the ship on April 11 and his wife who died later that month were both infected with hantavirus.
Van Kerkhove said this initial patient and his wife joined the ship in Argentina, where the Andes variant is known to spread. A person infected with hantavirus typically begins to show symptoms between one to eight weeks after exposure.
“Our assumption is they were infected off the ship, perhaps doing some activities there,” Van Kerkhove said. It is possible couples in close contact either had a common source of infection or one person infected the other, she said.
The WHO said the risk to the general public is low. Transmission of hantavirus on a cruise ship is very rare and human-to-human transmission of the Andes virus would likely occur through bodily fluids, said Dr. Neil Maniar , a professor of public health practice at Northeastern University. “This is really something that requires closer contact” for human-to-human transmission, Maniar said.
Exposure to hantavirus often occurs in enclosed or poorly ventilated spaces where rodents are present. In the Americas, the virus can cause hantavirus pulmonary syndrome, or HPS, a severe lung infection. Symptoms include fever, muscle aches and fatigue, and progress to coughing, shortness of breath and fluid in the lungs.
There are no vaccines or antiviral treatments for the syndrome. Doctors typically treat patients with supportive care, ranging from hydration to ventilation.
