Questions continue to swirl about the nation’s — and Michigan’s — readiness to face another global viral threat after about 150 passengers and crew from 23 countries aboard the MV Hondius cruise ship were exposed to the Andes strain of hantavirus, which so far has killed three people and sickened several more around the world.
In all, 41 Americans have returned to the U.S. after traveling on the cruise ship or being in close contact with passengers and are under monitoring by federal, state and local health officials, the CDC reported Thursday, May 14.
Eighteen U.S. citizens who were aboard the ship were taken May 11 via State Department airlift from the Dutch cruise ship in Tenerife, Spain, to biocontainment and quarantine facilities at the University of Nebraska Medical Center in Omaha and Emory University Hospital in Atlanta. They remained in isolation on Thursday as the U.S. Centers for Disease Control and Prevention continued to monitor their health for symptoms of the virus, which is deadly in about 35% of people.
The 18 people still under monitoring in Omaha and Atlanta are undergoing regular health assessments, which include temperature checks, symptom screening and general wellness evaluations, said Dr. Brendan Jackson, the CDC team lead in Nebraska.
“This particular virus has a long incubation period, so, the monitoring period is 42 days,” he said.
The remaining 23 Americans are scattered around the country and have been asked to stay home as their conditions are monitored by state and local health officials, said Dr. David Fitter, the CDC’s incident manager for hantavirus response.
Those 23 people include passengers who were aboard the MV Hondius but disembarked before the hantavirus outbreak was identified as well as close contacts of passengers aboard the ill-fated cruise who may have been exposed during travel, “specifically on flights where a symptomatic case was present,” Fitter said.
Testing concerns
The CDC has only one method of testing people for hantavirus: a serology test that uses a blood sample to check for specific antibodies associated with infection, he said.
“Testing is recommended only for those with symptoms, and decisions are guided by the best available evidence,” Fitter said. The U.S. doesn’t have the capability to use PCR (Polymerase Chain Reaction) tests, which can detect tiny amounts of viral genetic material, though other countries do.
The CDC said that PCR tests have not been licensed for use in humans in the United States.
Earlier in the week, the CDC reported one U.S. passenger had “inconclusive” and conflicting results from PCR tests processed internationally: one was negative and the other was positive. The CDC retested this passenger, but did not release the results Thursday, May 14. Another person who was symptomatic earlier in the week and is under monitoring at Emory in Atlanta also was tested. The U.S. Department of Health and Human Services posted to the social media platform X on May 12 that the “mildly symptomatic passenger” at Emory tested negative for the Andes hantavirus variant.
When Fitter was asked how many of the 41 Americans under public health monitoring have been tested by the CDC to date, and what the outcomes were, he said only this: “What I can say is that there are no cases in the United States currently, but again, with regards to testing, we want to be very cautious about patient confidentiality.”
He added: “If anyone develops symptoms, we’ve worked with their local health departments to ensure rapid access to testing and care.”
Yet the CDC also acknowledged that some states don’t have a laboratory equipped to process hantavirus serology tests.
The Michigan health department’s Bureau of Laboratories does not have the ability to run serology tests for the Andes hantavirus. If someone in Michigan develops symptoms of the disease and had contact with a case, samples would be sent to the CDC or to another lab with the capacity to test for the virus, said Laina Stebbins, a spokesperson for the Michigan Department of Health and Human Services.
Dr. Arnold Monto, emeritus professor of epidemiology and global public health at the University of Michigan and co-director of the Michigan Center for Respiratory Virus Research and Response, said hantavirus cases are so rare in Michigan, it’s not surprising that the state laboratory doesn’t have the capacity to test for it.
There has been just one known hantavirus case in Michigan, and it was the Sin Nombre strain identified in 2021 in a woman from Washtenaw County.
“It would take a major effort for every laboratory in the country to do testing,” Monto said. “It would probably take months. … The problem in working with this virus is you have to have super containment, which limits the number of places that can work with it. You need appropriate containment in order to handle it.”
Dr. Bobbi S. Pritt, professor of laboratory medicine and pathology and chair of the division of clinical microbiology at the Mayo Clinic, said during a news conference earlier this week that hantavirus testing in the U.S. is mostly limited to specialized reference laboratories, certain state and public health labs and the CDC.
The Mayo Clinic is one of the specialized reference labs with testing availability, she said.
“We do have a hantavirus serology test that we are working on making public so that people could use it through a physician’s order, but the testing is not readily available outside of those referral settings.”
At least for now, she said, U.S. testing capability “meets the needs at this time.”
Which states are monitoring people for hantavirus?
Citing privacy concerns, the CDC would not provide the home states or the medical conditions of the 18 U.S. citizens who are being encouraged to remain in isolation in Nebraska and Georgia or the other 23 Americans undergoing at-home monitoring.
However, announcements have been made by some state and local health departments about MV Hondius passengers and close contacts of passengers now under public health monitoring in those states. They include: Arizona, California, Georgia, Texas, Virginia, Washington, New Jersey, New York, Maryland, Minnesota and Kansas.
The Michigan Department of Health and Human Services reported May 14 that it has not been notified by the CDC of any Michigander who was aboard the cruise ship or who was exposed to the virus through contact with a passenger from the MV Hondius, but that contact tracing is continuing.
“We are ready to respond if that changes, as the investigation is ongoing,” Laina Stebbins, a spokesperson for MDHHS, told the Detroit Free Press.
Isolation, monitoring continues
Despite the known exposure to Andes hantavirus, no quarantine order has been issued for anyone in the United States who is associated with the MV Hondius cruise ship, which departed from Ushuaia, Argentina, on April 1, on what was supposed to be a 35-day expedition to remote islands in the south Atlantic, Fitter said.
Rather, the CDC hopes for the ongoing cooperation of the people who were aboard the ship and those who came into contact with them to remain in isolation for the full 42-day incubation period of this virus.
“Currently, there are no state or federal quarantine orders that have been drawn. We are working really closely with all contacts to ensure that they understand what is expected for them to appropriately monitor themselves,” Fitter said. “But we also want to make sure that they have the right information so that they understand the situation as best as possible.”
The CDC considers May 11 the first day of monitoring for the people who were taken by the U.S. government from the ship to Nebraska and Atlanta, he said.
“You may ask why CDC is not using our federal quarantining authority on people,” Fitter said. “Our approach is based on risk and evidence. We are working closely with passengers and public health partners to ensure monitoring and rapid access to care if symptoms develop. Our goal is to work with them and alongside them, building plans based on their specific situation to protect the health and safety of passengers and American communities.
“We understand that these passengers have already been through a difficult experience, and this coordinated approach reflects our respect for them as partners in keeping themselves and their communities safe.”
The monitoring and isolation timeline could be different for people who left the MV Hondius April 24, when the ship stopped at a port on the island of Saint Helena, a British overseas territory.
The World Health Organization reported 34 passengers and crew departed that day, although it’s unclear how many of them were Americans. Among them was a Dutch woman who was already sick with hantavirus and had gastrointestinal symptoms that worsened as she traveled on to Johannesburg, South Africa, on April 25, according to the Republic of South Africa’s National Institute for Communicable Diseases.
She then boarded a KLM flight headed to Amsterdam, but was too sick to make the trip. She collapsed at the Johannesburg OR Tambo International Airport and was taken to a nearby hospital on April 26, but did not survive. Her husband had died aboard the MV Hondius on April 11 of the same disease. A third ship passenger died May 2, according to the WHO.
The Andes strain of hantavirus is the only type known to spread from person to person as well as through contact with the droppings, urine and saliva of infected rodents. It also spreads when people inhale microscopic particles of the waste of infected mice and rats, which can occur when cleaning out places where rodents have been, such as garages, barns, sheds and basements.
Current research suggests people are most contagious when they are symptomatic, and that it takes close contact to spread it to another person, Monto said.
“I hope that’s correct,” he said, “because identifying asymptomatic linkages is very difficult. But if it behaves in the way we think it behaves, what we are doing, I think, is adequate.”
The disease is rare enough that some unknowns remain, he said.
“The real question is, what is close contact and how much contact does it take” to spread the disease from person to person? he asked, “and do you have to be exposed at a certain point in an individual’s illness to have transmission take place?”
With a 42-day incubation period, strict quarantine would be difficult to enforce for every person who shared commercial flights with all 34 MV Hondius passengers who disembarked on April 24.
“There would be so many people who would have to be strictly quarantined that it really would be logistically almost impossible to handle,” Monto said.
Instead, Monto said, it’s “rational” that public health leaders are focusing on monitoring and isolation for the people who were seated nearest to the ship’s symptomatic passengers on the planes.
“Now, if we see additional cases, then we may have to up what is being done,” Monto said. “But, right now, I think they’re doing the best they can with a relatively small number of cases.”
At least for now, Fitter said, state and local health departments are doing multiple daily checks with passengers from the MV Hondius and those who were their close contacts, and asking that they remain at home.
“Our goal is to ensure that we’re able to follow our monitoring guidelines, and to work with passengers to ensure that they are able to do it,” he said. “And if they need to do it somewhere else, we will work with them, we will work with our state and local health departments to make sure that happens as well. … The safety and health of the passengers is critical to us as well as the safety and health of the American communities.”
The WHO warned that more cases are likely.
“At the moment, there is no sign that we are seeing the start of a larger outbreak, but of course, the situation could change,” said Dr. Tedros Adhanom Ghebreyesus, director-general of the WHO. “And given the incubation period of the virus, it’s possible we might see more cases in the coming weeks. … Viruses do not respect borders.”
‘A little tricky’
Dr. Anand Parekh, chief health policy officer at the University of Michigan School of Public Health and senior adviser at the Institute for Healthcare Policy and Innovation, told the Detroit Free Press that given all the variables in this situation, the public health response is “a little tricky.”
With so many potential contacts of ship passengers, the varying timelines for when they disembarked and the 42-incubation period of the virus, it is likely there will be at least a couple cases of secondary transmission globally, he said.
However, Parekh said the outbreak still can be contained and doesn’t have the pandemic potential of other viruses, such as influenza and SARS-CoV-2, which caused the COVID-19 pandemic.
“This outbreak, I do think it will eventually burn out,” he said, given what is known about how the Andes hantavirus spread during previous outbreaks and the similarity in the genetic sequence of the virus that sickened passengers on the MV Hondius.
It is possible that passengers who are at home under monitoring aren’t following public health instructions, he said.
“There could be household members, you could be out and about going to grocery stores, going all over the place and when a nurse is calling once a day to ask: ‘How are you feeling? Or did you take your temperature?’ that’s very different than being (in a biocontainment or quarantine facility) at the University of Nebraska or Emory,” Parekh said.
Still, he hopes that people are taking the threat seriously.
“I hope that the instructions are very, very clear in terms of any kind of symptoms, any kind of fever, you need to report it to public health [officials] and at that point, you also need to be isolated,” he said. “Whenever you do at-home quarantine, you’re leaving it up to folks … and hopefully they understand the gravity, but it’s not easy. It’s not easy to be in a quarantine for 42 days.”
This situation, he said, is yet another reminder of the importance of funding public health and ensuring the nation is at the ready.
“Pandemic preparedness needs to be a top priority for any administration, particularly in the 21st century,” Parekh said. “In this era of animal-human interface, of climate change, deforestation encroachment, the likelihood of zoonotic spillover events is only going to increase.
“And so, when you have an administration that disbands the White House Office on Pandemic Preparedness and says that NIH (National Institutes of Health) will no longer consider pandemic preparedness to be a priority, when they cancel mRNA research, when they hollow out CDC and FDA [U.S. Food and Drug Administration]. When they don’t have any public health professionals at the head of CDC, and the surgeon general and the FDA, then it’s not really surprising that the administration over the last seven to 10 days were a bit behind the eight ball.”
Contact Kristen Shamus: kshamus@freepress.com.
This article originally appeared on Detroit Free Press: Questions swirl about U.S., Michigan’s ability to quell hantavirus
Reporting by Kristen Jordan Shamus, Detroit Free Press / Detroit Free Press
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