Tséhootsooí doctor says cruise outbreak differs from local hantavirus

WINDOW ROCK

As international health officials monitor a deadly hantavirus outbreak linked to an Antarctic cruise ship, a doctor at Tséhootsooí Medical Center says the virus involved is different from the hantavirus long known on the Navajo Nation and in the Four Corners region.

Dr. Alithea Gabrellas said the virus connected to the cruise ship outbreak is Andes virus, a hantavirus strain found in South America that is carried by rodents native to Argentina and nearby regions. The strain found on the Navajo Nation is Sin Nombre virus, which is spread by deer mice common throughout the Four Corners.

“While those viruses are in the same family, they’re not the same,” Gabrellas said during a May 7 interview with the Navajo Times.

Andes virus is most commonly linked to infected rats in South America. People become infected through exposure to rodent urine, droppings or nesting materials. Sin Nombre virus, which has caused serious illnesses and deaths in the Four Corners for decades, is tied specifically to deer mice.

Gabrellas said the most important distinction is that Sin Nombre virus does not spread from person to person.

“People only catch it from infected mice,” Gabrellas said.

Rare person-to-person transmission of Andes virus has been documented, usually involving prolonged close contact or exposure to bodily fluids.

The World Health Organization reported in a May 4 public alert that limited human-to-human spread of Andes virus has been observed before, though such cases remain uncommon. The WHO and the U.S. Centers for Disease Control and Prevention both stated that the public risk from the outbreak remains low.

Cruise outbreak remains low risk

The outbreak is tied to the MV Hondius, an expedition cruise vessel operated by Dutch company Oceanwide Expeditions. The ship departed Argentina on April 1 for a multiweek voyage through Antarctica and South Atlantic islands.

As of May 7, WHO Director-General Tedros Adhanom Ghebreyesus said eight hantavirus cases had been identified aboard the vessel, including five confirmed and three suspected cases. Three people have died.

International laboratories confirmed the virus as Andes hantavirus.

Health officials believe a Dutch couple contracted the virus during a bird-watching excursion in Ushuaia, Argentina, before boarding the ship. The husband died aboard the vessel on April 11. His wife later died during a flight to Johannesburg, South Africa, after leaving the ship at Saint Helena.

Three additional passengers were removed from the ship near Cape Verde on May 6. Two were seriously ill and transported to the Netherlands for medical treatment. Another passenger, who had close contact with one of the deceased but showed no symptoms, returned to Germany.

More than 140 passengers and crew members remain aboard the vessel as it heads toward Spain’s Canary Islands.

The Arizona Department of Health Services confirmed Thursday that one Arizona resident who had been aboard the ship is being monitored for 42 days, the longest known incubation period for Andes virus.

Dr. Joel Terriquez, the medical director for preparedness at the Arizona Department of Health Services, said the resident has shown no symptoms and currently poses a very low risk to others.

State officials have not publicly identified where in Arizona the traveler lives.

At least seven people in five states are being monitored after returning from the voyage. Health officials in Georgia, Texas, Virginia and California are also tracking passengers. None have developed symptoms.

Gabrellas said the risk to the Navajo Nation remains very low.

“I don’t think it’s a high level of threat to the Navajo Nation,” Gabrellas said.

She said the primary rodent-related health concern in the Four Corners remains Sin Nombre virus, which continues to cause occasional severe infections each year.

According to the WHO and the CDC guidance, hantavirus pulmonary syndrome caused by Sin Nombre virus has no approved antiviral treatment or vaccine. Severe cases can rapidly become life-threatening once lung symptoms develop.

Cleaning risks remain low concern

Gabrellas warned that routine spring-cleaning activities remain one of the biggest risk factors for exposure in rural communities.

“It’s very important not to vacuum up or try to sweep up rodent droppings,” Gabrellas said. “Vacuuming or sweeping puts the virus in the air.”

She said residents should air out sheds, barns, garages, vehicles and storage buildings for at least 30 minutes before entering. Rodent droppings and nesting material should be sprayed with disinfectant or a bleach solution before cleanup.

Rubber or plastic gloves should be worn throughout the cleaning process, she said. Heavily contaminated areas should be cleaned while wearing an N95 mask.

A CDC and Tséhootsooí Medical Center training manual identifies cleaning abandoned buildings, storage sheds and garages as some of the most common exposure risks. Farming, ranching, construction work and camping activities can also increase exposure risk.

Gabrellas also addressed concerns about other diseases found in the region.

She said bubonic plague remains present in parts of the Four Corners but is generally spread through fleas carried by prairie dogs and other animals, not deer mice.

Residents who hunt or handle prairie dogs should wear gloves, she said. Large prairie dog die-offs should be reported to tribal or state health officials.

Gabrellas said Q fever, another disease found in the region, is associated primarily with sheep and goats and can spread through exposure to fluids during birthing.

She also expressed concern about declining federal public health staffing and funding.

Gabrellas said tribal communities are especially vulnerable when federal public health programs lose funding because many tribal health systems rely heavily on federal partnerships and technical support.

She pointed to a 75-page CDC and Tséhootsooí Medical Center training manual published in 2022 that teaches laboratory workers how to quickly identify likely hantavirus cases using a “five-point hantavirus screen.”

The screening system, first developed by researchers at the University of New Mexico Health Sciences Center, allows laboratory staff to flag possible infections in roughly 30 minutes using standard blood tests.

According to the manual, the screening process is highly accurate when several warning signs appear together in a patient’s bloodwork.

Tséhootsooí Medical Center began using the screening method in 2016 and has since trained hospital workers and outside laboratories, including medical staff in Mono County, California, during a hantavirus outbreak there.

Gabrellas said tribal leaders should continue supporting vaccine education and stable federal public health funding.

“Cuts to federal public health programs hit tribal nations hardest,” Gabrellas said.

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