Last November, Jay Bhattacharya, the director of the National Institutes of Health and an acting director of the Centers for Disease Control and Prevention—the man has had nearly as many jobs as Marco Rubio—wrote a short piece with the N.I.H.’s principal deputy director for the conservative publication City Journal. The piece argues that the country should largely stop trying to surveil for new pathogens, assess the risk they pose to humans, or develop vaccines and drugs to manage them. These activities, the authors suggest, mostly serve to keep scientists happy and funded. Instead, the public should be encouraged to become “metabolically healthy” by, for example, “eating nutritious food” and “getting up and walking more.” Bhattacharya has railed against the politicization of science, but the piece concludes that the best way to prepare for deadly pandemics is by “making America healthy again.”

At a time of escalating viral threats, this is a take better suited to online feuds than to biosecurity strategy from the apex of American public health. Last month, the ill-fated Dutch cruise ship M.V. Hondius left Argentina carrying around a hundred and seventy-five people from some two dozen countries. What followed is well documented: a seventy-year-old man developed fever, diarrhea, and severe respiratory distress; he died of what turned out to be a hantavirus infection. Soon afterward, two more passengers sickened and died, and at least eight others were infected. Dozens of people have since returned to their home countries to quarantine, but the process has been less than airtight. After disembarking, a Turkish travel influencer attended a wedding in Istanbul; a British man exposed to the virus was tracked down in a bar in Milan.

Hantaviruses are usually found in rodent droppings, and they spread when someone inhales aerosolized particles or eats foods contaminated by them. But the version of the virus on the ship, known as the Andes strain, can transmit directly from person to person through bodily fluids or the air. There are no specific vaccines or treatments for the virus, which can cause a life-threatening condition known as hantavirus cardiopulmonary syndrome, whereby fluid pours out of the capillaries and into the lungs. The death rate is as high as fifty per cent. Notably, the first known hantavirus death in the U.S., in 1993, was of a nineteen-year-old marathon runner. Metabolic health only gets you so far.

Health authorities have sought to ease concerns about the outbreak. Federal officials have avoided using the word “quarantine,” and the C.D.C. didn’t activate its Emergency Operations Center or issue an advisory to health departments until some American passengers of the ship had already returned to the U.S. The agency has indicated that the risk to the public remains low, because transmission requires “prolonged close contact,” but what, exactly, constitutes “prolonged” and “close” is a matter of some dispute.

According to a report in The New England Journal of Medicine, hantavirus has previously been implicated in superspreader events. In 2018, a person infected with the virus attended a birthday party in Epuyén, Argentina. At least five people sitting nearby developed symptoms, including a man with an “active social life,” who went on to infect half a dozen other people before dying, a few weeks later. The man’s wife is thought to have infected ten more people at his wake. All told, nearly three dozen people contracted the virus, and eleven died. The report’s authors estimated that, before mitigation measures such as patient isolation were initiated, the virus’s reproduction number was above two, meaning that each infected person spread the virus to more than two others. (The initial COVID strain had a reproduction number of around three.) Hantavirus can incubate for nearly two months before a person shows symptoms, and several dozen Americans are now being monitored at U.S. quarantine facilities or in their homes. The full extent of the outbreak may not become clear for weeks.