On April 24, nearly two weeks after the first person aboard a cruise ship died of hantavirus, 30 passengers, including six Americans, disembarked in St. Helena, a remote island in the Atlantic Ocean.

The Americans are now back on U.S. soil, and three states are monitoring them; none have shown symptoms so far. That information came on Wednesday — not from the Centers for Disease Control and Prevention or from the State Department, which is coordinating the nation’s response to the hantavirus outbreak, but from the medical news publication MedPage Today. (The New York Times confirmed the report with state officials.)

More than four hours after the news emerged, the C.D.C. issued its first public statement about the outbreak, saying, “We are working closely with our international partners to provide technical assistance and guidance to mitigate risk.” It did not mention the Americans who were back in the country or efforts to monitor them.

It was only a day earlier, on Tuesday, that the agency had set up a team to respond to the outbreak, nearly a month after the first patient had died.

To some public health experts, the alarming thing about this situation is not the hantavirus, which they note spreads among people rarely, and only with close contact over a period of time rather than casual interactions. It is that the administration’s sluggish response and lack of communication suggest the United States is ill prepared for a larger health crisis, such as another pandemic.

“We should be able to deal collectively with a hantavirus outbreak much more quickly and effectively than this is happening,” said Stephanie Psaki, the coordinator for global health security during the Biden administration.

“An outbreak of a known pathogen on a cruise ship is a relatively easy scenario,” she said. “It can get much harder than this.”

Because of deep staffing cuts the Trump administration has made to the C.D.C. and other health agencies, the government has far fewer people to respond to outbreaks, from trainees and contractors who can be deployed to do boots-on-the-ground epidemiology to senior leaders who can coordinate responses across the U.S. government and elsewhere. And because President Trump withdrew the country from the World Health Organization, the United States does not receive regular information from member states about emerging health threats.

The State Department did not respond to questions about plans to repatriate the 17 Americans still on board the ship or to monitor those already back home. “We are closely tracking reports of the suspected hantavirus outbreak on a cruise ship in the Atlantic Ocean and are in close contact with the cruise ship and U.S. and international health authorities,” the department said in an emailed statement.

It directed questions about quarantining the passengers to the C.D.C. The Health and Human Services Department, which manages communications from the agency, also did not respond to questions about repatriation or quarantine.

The first patient aboard MV Hondius, a Dutch cruise ship, was an older man who developed fever, headache and mild diarrhea on April 6. He died of respiratory distress five days later, but his body stayed on the vessel till April 24. The second patient, a close contact, died on April 26 and a third on May 2. As of Thursday, five other people have symptoms resembling those of hantavirus infection.

South African scientists identified hantavirus as the cause of the illnesses on May 2. But if the U.S. government had been more involved, “things could have happened more quickly at every step along the way,” Dr. Psaki said.

The World Health Organization was notified of the cluster of illnesses via International Health Regulations, a legal framework that requires member countries to disclose outbreaks. After the Trump administration withdrew from the W.H.O. in January 2025, it rejected the latest regulations that July. As a result, the United States is not privy to many of the conversations between member states.

Even if the C.D.C. and the W.H.O. are talking now, “what you want is to have an ongoing dialogue,” said Dr. Daniel Jernigan, who ran the C.D.C.’s emerging disease center before resigning in August in protest of the administration’s handling of the agency.

“C.D.C. is not a part of that routine engagement,” he said. “And therefore when something emerges, we’re not going to get that call immediately.”

The agency’s delay in setting up a team to respond to the outbreak is worrying, infectious disease experts said. Ideally, the risk to Americans should be assessed and communicated to health agencies and the public as soon as a threat emerges, usually within 24 to 48 hours, Dr. Psaki said.

“The point is early decision making, proactive plans to protect Americans, and people with outbreak response expertise in the lead,” she added.

Unless the administration fills crucial leadership roles focused on infectious disease threats, it is likely to be hamstrung when bigger threats come along, she and others said.

“Leaders with convening power and influence are key,” said Dr. Jeanne Marrazzo, chief executive of the Infectious Diseases Society of America. Dr. Marrazzo directed the National Institute of Allergy and Infectious Diseases but was fired after filing a whistle-blower complaint against the Trump administration.

“They can work from the White House to the H.H.S. agencies to industry and academic partners to be sure there is a coordinated effort to galvanize the response,” she added. “We don’t have that right now.”

Dr. Psaki’s former role, created by Congress in 2023 to oversee preparedness to biological threats, is vacant. The White House Office of Pandemic Preparedness and Response Policy, established by Congress in 2022, is also unstaffed — fulfilling in spirit, if not in fact, President Trump’s threat during his campaign to shut it down.

In February 2025, the administration appointed Gerald Parker, a former commander of the U.S. Army Medical Research Institute of Infectious Diseases, to lead the biosecurity and pandemic response directorate within the National Security Council. But he resigned less than six months into the job, and has not been replaced.

The White House did not respond to questions about those roles.

Last year, alongside massive cuts to research on mRNA and other vaccines, the Trump administration shuttered a network of research centers focused on preventing pandemics by studying pathogens like hantavirus that can jump from animals to people.

In its 2026 budget request, the administration said it planned to refocus the C.D.C. on outbreak investigations and preparedness. But at the same time, it proposed eliminating about $750 million in preparedness grants that states rely on to cope with natural and man-made disasters including outbreaks. It also zeroed funding for the Hospital Preparedness Program, which strengthens health care systems to respond to emergencies, saying the program “has been wasteful and unfocused.”

Nearly all of the C.D.C.’s center directors were appointed recently or are serving in an acting capacity. The agency has also lost the heads of several important divisions, including the Division of High-Consequence Pathogens — which includes hantavirus — who now works for the New Zealand government.

“You don’t have the captains and admirals in order to run a big, big response,” Dr. Jernigan said. The agency has also added layers of bureaucracy to get travel approved for scientists who might need to investigate outbreaks, he said.

The layoffs largely spared other staff from the agency’s infectious disease centers. But because of a hiring freeze, the agency has not renewed contracts for Title 42 workers, a category that includes scientists hired for specialized roles. It has also let go of younger fellows, including in a program called ORISE, who could be deployed for various tasks, including testing at air or seaports.

The thinning numbers have shrunk the number of qualified scientists who can assist states with testing and management of dangerous pathogens. By July, the C.D.C.’s rabies team will be down to just one person with the clinical expertise to advise state and local officials, and the pox virus team will have none.

The administration twice fired, then brought back, the C.D.C.’s vaunted “disease detectives,” Epidemic Intelligence Service fellows who conduct outbreak investigations. Many of the reinstated fellows have left the agency for other jobs, and applications for the incoming class are roughly 20 percent of what they would be by this time, according to data shared at a recent conference of the fellows.

The effects of the Trump administration’s cuts to infectious disease research are also being felt more globally. South Africa has the capacity to sequence the hantavirus at least in part because of investments prior administrations made through the President’s Emergency Fund for AIDS Relief, Dr. Carlos del Rio, an infectious disease expert at Emory University, told reporters on Thursday.

But the Trump administration has decimated the research system in South Africa and is pulling back support for PEPFAR.

“I worry that as we disinvest in global health, we’re losing our capacity, our global capacity, to deal with diseases,” Dr. Del Rio said.

Tulio de Oliveira, director of the Centre for Epidemic Response and Innovation at Stellenbosch University in South Africa, said the W.H.O.’s advisory group on viruses with pandemic potential would meet on Monday to discuss the latest findings on the hantavirus.

The group includes about two dozen experts from various countries including Brazil, Britain, India and the Netherlands. It does not include anyone from the C.D.C.

“Especially at the moment, it doesn’t seem that the C.D.C. is very functional,” he said.