Outbreak of hantavirus among cruise ship passengers shows how deadly the rodent-borne illness can be
A concern among hikers in the American Southwest, deadly hantavirus on a Dutch cruise ship may be a rare case of human-to-human transmission
The deaths of three people aboard a small cruise ship during a suspected outbreak of hantavirus demonstrate the potential deadliness of the rodent-borne illness.
“Once somebody gets sick, once somebody comes in contact with hantavirus, they can develop severe illness fairly quickly,” said Neil Maniar, director of Northeastern’s master of public health program.
Caused by contact with urine, feces or saliva from certain species of rats or mice, hantavirus occurs across the globe, says the World Health Organization, or WHO, a United Nations agency that sets standards for international public health. But mortality runs higher in the Americas than in Europe and Asia, with a fatality rate of up to 50% compared with a rate of up to 15%
Early symptoms are similar to the flu, said Joshua Merson, program director of extreme medicine at Northeastern University. “What makes it dangerous is what comes after the initial symptoms,” he said. “The virus triggers [leaking of blood vessels] that floods the lungs with fluid, causing rapid respiratory failure.”
The passengers who fell ill reported a variety of symptoms, including fever, gastrointestinal problems, signs of pneumonia and trouble breathing, according to WHO.
The hantavirus cluster on the MV Hondius cruise ship is suspected to also be a rare case of human-to-human transmission. The cruise originated in Argentina, where a hantavirus strain called Andes virus is known to spread from person to person, WHO said.
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It’s possible a passenger became infected on a shore excursion and spread the virus in the closed environment of the cruise ship, Maniar said.
The Hondius, with 147 passengers and crew, followed an itinerary that included Antarctica and remote Ascension Island in the Atlantic, but has been isolated off the coast of Cape Verde near the African continent waiting to find a port where it can safely dock.
The first sign of trouble came when a Dutch citizen developed symptoms of fever, headache and mild diarrhea on April 6, five days after the ship left the port of Ushuaia, according to a report issued by WHO.
The man was overcome by respiratory distress and died on April 11. His wife, who developed GI symptoms shortly afterward, succumbed on April 26 in a hospital in South Africa after trying to fly home, the health agency said. The third victim, also a woman, passed away May 2 after coming down with a fever and “a general feeling of being unwell” April 28, WHO said.
Among the four others sickened, one man is in intensive care in a hospital in South Africa after being medically evacuated from Ascension Island on April 27, three days after developing fever, shortness of breath and signs of pneumonia.
Of the seven total cases recorded thus far, two have been confirmed to be hantavirus and the others are classified as suspected cases, according to WHO.
There is no vaccine or specific treatment for hantavirus.
Stephen P. Wood, an emergency medicine provider and program director for Northeastern’s adult gerontology acute care nurse practitioner program, Wood, said patients receive supportive care including IV fluids, supplemental oxygen and vasopressor medication to increase blood pressure.
In severe cases, patients may be put on ventilators or portable bypass machines called ECMOs, Wood said.
Cases of hantavirus in the U.S. are rare, with only about 20 to 50 cases being reported to the Centers for Disease Prevention Control annually.
But with a fatality rate of 40% in the U.S., people who work in extreme medicine in wilderness environments are on the lookout for hantavirus pulmonary syndrome or HPS, a complication of hantavirus, Merson said.
Hikers, campers and other people engaged in outdoor recreation in Western states are among those at risk of both the syndrome and potentially deadly outcomes if their case is missed.
The strain relevant to U.S. hikers is known as Sin Nombre, which is carried by deer mice. Merson said the Sin Nombre strain can be found in cabins and trail sheds that may be visited more frequently by rodents than hikers. People typically get exposed when urine, feces or saliva gets “aerosolized into viral particles” that are inhaled, Wood said.
Unlike the Andes virus, the Sin Nombre strain does not spread person to person, Merson said. It also differs from strains found in Europe and Asia that cause Hemorrhagic Fever with Renal Syndrome. That syndrome can result in severe kidney damage but tends to have a lower mortality rate.
Hantavirus hit the headlines last year, when actor Gene Hackman and his wife, 65-year-old Betsy Arakawa, were found dead on their property in New Mexico. State medical examiners determined that Arakawa was killed by HPS and that the 95-year-old Hackman died about a week afterward of natural causes, including Alzheimer’s disease.
The New Mexico Department of Health said Arakawa may have come into contact with rodent droppings or nests on her property’s outbuildings.
The key to prevention includes sealing points of entry into buildings from rodents, wearing a mask and gloves when cleaning up after rodents, using wet sponges or clothes to clean potentially contaminated surfaces with disinfectants instead of sweeping or vacuuming, and storing food in sealed containers, Wood and Merson said.
In the meantime, WHO said it continues to investigate the cause of the Hondius cruise ship cluster as it now works with Spain to allow the ship to dock in the Canary Islands.
