A rare and often deadly rodent-borne illness has drawn fresh attention after an outbreak on a cruise ship off West Africa killed three people and sickened several others, leaving passengers stranded. While the vessel is anchored near Cape Verde, the disease, known as hantavirus, is also present in the United States, with federal data showing it is far more common in some regions than others.
The World Health Organization confirmed Tuesday that seven respiratory illness cases have been reported among the 147 passengers and crew aboard the ship. Two of those were confirmed as hantavirus, and the remaining five are suspected to be the same. Three patients have died, one is critically ill, and the rest have mild symptoms. The WHO said the outbreak is being managed and investigations continue.
Hantavirus is spread through contact with rodents or their urine and droppings. In the U.S., deer mice are the primary carriers. The virus does not typically spread between people, though the WHO warns rare instances have occurred. There is no specific treatment or cure, but early medical attention improves survival odds.
“It really starts like the flu: body aches, feeling poorly overall,” said Dr. Sonja Bartolome of UT Southwestern Medical Center in Dallas. “Early in the illness, you really may not be able to tell the difference between hantavirus and having the flu.”
Infection can rapidly progress to hantavirus pulmonary syndrome, a life-threatening lung condition. Betsy Arakawa, the wife of actor Gene Hackman, and multiple California residents died from the syndrome last year. The CDC began tracking the virus after a 1993 outbreak in the Four Corners region, where Arizona, Colorado, New Mexico, and Utah meet.
Through 2023, the most recent data available, the CDC has confirmed nearly 900 hantavirus cases in the U.S. Roughly half were reported in the Four Corners region and California, including more than 120 each in Colorado and New Mexico. A study published last year by University of New Mexico researchers found that over 30 rodent and small mammal species in the Southwest carry the virus, though the exact reason for the geographic concentration remains unclear.
Dr. Steven Bradfute, an associate professor at the university’s Center for Global Health, suggested that the virus strain in northwestern New Mexico may differ from that in the southeast. While deer mice are found throughout North America, states with double-digit case counts over the past 30 years are all west of the Mississippi River.
Ten states have reported no hantavirus cases since 1993: Alaska, Hawaii, Missouri, Mississippi, Alabama, Georgia, South Carolina, Kentucky, Ohio, and New Jersey. The hantavirus outbreak on the cruise ship has renewed concern, but public health experts stress the best prevention is minimizing contact with rodents and their droppings. They recommend using protective gloves and a bleach solution for cleanup, and caution against sweeping or vacuuming, which can aerosolize the virus.
