The Trump administration has failed to fill crucial public health positions across the government, leaving the nation ill-prepared to face one of its greatest potential threats: a pandemic outbreak of a deadly infectious disease, according to experts in health and national security.

No one knows where or when the next outbreak will occur, but health security experts say it is inevitable. Every president since Ronald Reagan has faced threats from infectious diseases, and the number of outbreaks is on the rise.

Over the past three years, the Centers for Disease Control and Prevention has monitored more than 300 outbreaks in 160 countries, tracking 37 dangerous pathogens in 2016 alone. Infectious diseases cause about 15 percent of all deaths worldwide.

But after 11 weeks in office, the Trump administration has filled few of the senior positions critical to responding to an outbreak. There is no permanent director at the CDC or at the U.S. Agency for International Development. At the Department of Health and Human Services, no one has been named to fill sub-Cabinet posts for health, global affairs, or preparedness and response. It’s also unclear whether the National Security Council will assume the same leadership on the issue as it did under President Barack Obama, according to public health experts.

“We need people in position to help steer the ship,” said Steve Davis, the chief executive of PATH, a Seattle-based international health technology nonprofit working with countries to improve their ability to detect disease. “We are actually very concerned.”

Residents of the town of Kailahun, Sierra Leone, gather along a river at dusk in August 2014. The town was deeply affected by that year’s Ebola outbreak. (Pete Muller/Prime for the Washington Post)

In addition to leaving key posts vacant, the Trump administration has displayed little interest in the issue, health and security experts say. The White House has made few public statements about the importance of preparing for outbreaks, and it has yet to build the international relationships that are crucial for responding to global health crises. Trump also has proposed sharp cuts to government agencies working to stop deadly outbreaks at their source.

The slow progress on senior-level appointments — even those, such as the CDC director, that do not require Senate confirmation — is hobbling Cabinet secretaries at agencies across the government. Temporary “beachhead” teams the White House installed are hitting the end of their appointments. The remaining civil servants have little authority to make major decisions or mobilize resources.

An HHS spokeswoman declined to comment on personnel decisions. An NSC official, who was not authorized to speak publicly, said the administration recognizes that global health security is a national security issue and that America’s health depends on the world’s ability to detect threats wherever they occur.

Trump’s NSC does not have a point person for global health security as Obama’s did, but global health security is part of the overall portfolio of Tom Bossert, Trump’s homeland security adviser, another NSC official said.

Global health experts warn that a pandemic threat could be as deadly as a nuclear attack — and is much more probable.

A global health crisis “will go from being on no one’s to-do list to being the only thing on their list,” said Bill Steiger, who headed the HHS office of global health affairs during the George W. Bush administration. He spoke at a panel on pandemic preparedness in early January. He is now part of Trump’s beachhead team at the State Department.

Next month, the G-20 governments, which traditionally focus on finance and economics, will convene their health ministers for the first time, in part to test coordination and preparedness for a pandemic, according to German officials, who are hosting the summit in Berlin. It’s not clear who will represent the United States.

View Graphic What's getting cut in Trump's budget

In a speech to a security conference in Munich earlier this year, billionaire Bill Gates said a pandemic threat needs to be taken as seriously as other national security issues.

“Imagine if I told you that somewhere in this world, there’s a weapon that exists — or that could emerge — capable of killing tens of thousands, or millions of people, bringing economies to a standstill and throwing nations into chaos,” said Gates, who has spent billions to improve health worldwide.

“Whether it occurs by a quirk of nature or at the hand of a terrorist, epidemiologists say a fast-moving airborne pathogen could kill more than 30 million people in less than a year.”

The projected annual cost of a pandemic could reach as high as $570 billion.

Last month, Trump met with Gates at the White House. After the meeting, press secretary Sean Spicer said the two had “a shared commitment to finding and stopping disease outbreaks around the world.”

Americans are at greater risk than ever from new infectious diseases, drug-resistant infections and potential bioterrorism organisms, despite advances in medicine and technology, experts say. Not only has the total number of outbreaks increased in the past three decades, but the scale, impact and methods of transmission also have expanded because of climate change, urbanization and globalization.

The outbreak of Ebola that erupted in West Africa eventually infected more than 28,000 people and killed more than 11,000. MERS has killed nearly 2,000 people in 27 countries. Health officials around the world are monitoring a strain of deadly bird flu, H7N9, that is causing China’s largest outbreak on record, killing 40 percent of people with confirmed infections.

(Gillian Brockell/The Washington Post)

Of all emerging infectious disease threats, a global influenza outbreak is everyone’s worst fear because it could be highly lethal and highly contagious. A particularly virulent influenza pandemic that started in 1918 killed an estimated 50 million people. Today’s H7N9 strain poses the greatest risk of a pandemic if it evolves to spread easily from human to human, according to U.S. officials.

Last month, several Democratic lawmakers wrote HHS Secretary Tom Price to raise concerns about the nation’s ability to respond to infectious disease threats. They also asked about the vacancies and the impact of proposed budget cuts in the event of a flu pandemic. They received no response.

“Our whole community is kind of ear to the ground trying to figure out any clues we can discern,” said Rebecca Katz, co-director of the Center for Global Health Science and Security at Georgetown University’s Medical Center.

Global health security “is clearly an issue that needs to be taken up by the heads of state,” said one European official who declined to be identified because her government does not want to appear critical of the United States. Diseases travel fast and don’t recognize borders. In today’s connected world, a disease can be transported from a rural village to any major city within 36 hours.

“It’s not just from travel of people, but birds, too,” she said. Referring to Trump’s proposal to build a wall along the border with Mexico, she added: “You can’t build walls to stop birds.”

Global health security was a top priority for the Obama administration, which launched a partnership in early 2014 to prevent deadly outbreaks from spreading. Experts say the collaboration, known as the Global Health Security Agenda, has raised the political profile of infectious disease threats and strengthened basic public health systems in the countries least equipped to fight epidemics.

In Cameroon, the government developed a new emergency operations center able to respond within 24 hours to an outbreak of a highly lethal bird flu last year, removing more than 67,000 birds that had the potential to spread the virus to humans. In 2015, it took the country eight weeks to respond to a cholera outbreak.

In Mali, personnel who received epidemiology training began vaccination campaigns the day after detecting a measles outbreak last year.

In addition, more than 30 countries have taken part in evaluations to assess their ability to detect and prevent outbreaks, and their “report cards” are made public to spur governments to take action. But the gains made so far are “still fragile and require continued funding until they are strong,” according to an internal CDC analysis.

The Obama administration committed $1 billion to the program, which is due to end in fiscal 2019. Although it has strong support among global health officials and some Republican lawmakers, the Trump administration has yet to say whether it plans to continue funding the initiative.

President Obama also brought up global health regularly in meetings with foreign leaders. Trump has said little since taking office, except for a reference in his inaugural speech about his desire to rid the earth of disease.

During the Ebola outbreak, Trump tweeted that health workers should be blocked from returning to the United States, despite advice from the CDC and other experts that doing so would not protect U.S. health and would harm efforts to stop the outbreak.

The administration’s proposed budget is also problematic, health experts say.

If approved by Congress, Trump’s request for the current fiscal year would slash the entire $72 million budget for global health security at USAID. And his request for fiscal 2018 calls for a nearly 18 percent cut at HHS, which includes the CDC.

The request does propose a new federal emergency fund intended to allow HHS to respond to emerging public health outbreaks. However, administration officials have provided few details.

Many Republican lawmakers have criticized the requests, saying Congress is unlikely to approve such deep cuts to health agencies.

“You can have the best people in the world, but if you’re slashing the NIH budget by 20 percent, and presumably the same thing to CDC, then I don’t care how good your people are, they’re not going to be nearly as effective as they need to be,” said Rep. Tom Cole, (R- Okla.), who chairs the House Appropriations subcommittee on labor, health and human services, education, and related agencies.

The health agencies are “the front lines of defense for the American people for some pretty awful things,” Cole said. “If the idea of a government is to protect the United States and its people, then these people contribute as much as another wing on an F-35 [fighter jet], and actually do more to save tens of thousands of lives.”

Lisa Rein contributed to this story.