The system didn’t catch the hantavirus threat. Biology saved us.

This week, I wrote an op-ed in the Boston Globe with my colleague Dr. Nikki Romanik on how the hantavirus outbreak underscores our need for better biological threat detection systems. We are dismantling critical infrastructure and cannot rely on current surveillance to raise alarm after the fact.

As of Monday, the World Health Organization had reported nine hantavirus cases linked to the expedition cruise ship MV Hondius — with seven confirmed infections of the Andes strain and two probable infections. Three people are dead. The ship, refused entry by port after port, finally docked in the Spanish Canary Islands. The first positive identification of hantavirus infection among ship passengers was May 2, while the first death on the ship was April 11. As of April 24, 25 percent of the passengers had already disembarked.

The Andes strain is the one hantavirus capable of spreading from person to person. North America has its own strain, Sin Nombre (or Unnamed in Spanish), which is not known to spread between people. If there were an outbreak of the Andes strain in rural Nevada or even Washington, D.C., would health officials know? Almost certainly not. Not before it had spread far and wide.

Passengers began falling ill weeks before hantavirus was identified. The ship continued its voyage. Some passengers disembarked. They flew home — to Switzerland, to South Africa, to the United States. They went through airports. They returned to their families. By the time two laboratories confirmed the diagnosis, the passengers who carried the virus were already scattered across the globe.

This is a pattern that has been repeated. The original SARS virus in 2003 spread from Guangdong, China, to Hong Kong to 29 countries before it had a name. COVID-19 was probably seeding multiple continents before the first genome was published. By the time health officials understood what the world was facing, COVID was everywhere.

We only catch outbreaks in retrospect.

Sin Nombre virus, carried by deer mice, has circulated quietly in the American West for decades. Last year, Betsy Arakawa — wife of actor Gene Hackman — died from hantavirus in her home in Santa Fe, briefly raising the alarm about a long-ignored threat.

The strain she likely had cannot spread person-to-person yet, but viruses evolve. And Andes itself could arrive here. An infected traveler with flu-like symptoms could spread it widely here before anyone suspects it.

Hantavirus became a nationally notifiable disease in 1995. When a doctor suspects it and actually tests a patient (not a guarantee for a rare disease) and if the patient tests positive, then the physician should file a report so the case can get counted.

The United States does not have continuous, pathogen-agnostic biological intelligence. It has a passive, symptom-triggered system that requires a sick person, an alert physician, and a correct diagnosis to register a single data point. That is what is called surveillance. It’s actually just case counting after the fact.

The Hondius timeline illustrates what this means. Passengers were sick. No system flagged it. The detection happened the old-fashioned way — sick people, worried doctors, weeks of elapsed time. If Andes transmitted as readily as influenza does, the passengers who scattered across the globe before the diagnosis was made would have seeded a large global outbreak. We are lucky that biology is on our side this time.

The Centers for Disease Control and Prevention has lost more than 3,000 staff in the past 15 months. The United States has also withdrawn from the World Health Organization, eliminating capacities that would activate on day one of a novel emergence.

The Trump administration has been making cuts over the past 15 months, not because health threats have diminished but because of its desire to undo the work of the Biden administration. Our nation has built satellites and other surveillance systems because leaders decided that threat was worth watching. Biological threats deserve the same logic.

The CDC’s National Wastewater Surveillance System covers 145 million Americans weekly — but it is geographically incomplete, concentrated in urban counties, and designed around detecting a small number of well-known pathogens. Congress should expand it into other areas and support expanding its capabilities. A single outbreak response runs into the billions of dollars, as it did for outbreaks of Ebola and H1N1. The surveillance system costs a fraction of that.

Beyond wastewater, a true early warning system pairs environmental sampling with metagenomic sequencing capable of detecting pathogens before health officials know what to look for. What has been missing is the political will. This technology is here and ready for prime time. If it were in use today, health officials would know if the Andes strain was in the United States or not. Instead, we will need to wait for weeks to see if additional people test positive.

This outbreak will almost surely not become a pandemic. But let’s be honest about what we mean by near-miss: The way that pathogen spreads saved us. The system didn’t.

The Hondius timeline is identical to what we would face if a novel pathogen boarded the Hondius ship. Or arrived at the same airport where one of the ship’s passengers, who later died, arrived. Or emerged from the same rural reservoir. We keep watching outbreaks through the rear view mirror, reconstructing what happened after impact.

Three people are dead. Nine cases reported. Seven confirmed infections and two probable cases. A ship that was turned away from port after port has now docked in Tenerife — and dozens of passengers are already home, having passed through airports before anyone knew what they carried. The FIFA World Cup arrives on American soil in weeks. The Olympics follow. International travel has fully recovered, if not exceeded, pre-pandemic levels. This is the permanent baseline — a world of high-volume global mixing that our biosurveillance system, which is being actively dismantled, was not built to monitor.

The gap hantavirus is exposing is not about hantavirus. It is about every pathogen that hasn’t come out in the open, moving through the same blind spots, with no guarantee the next one’s biology will bail us out.

The technology to address this exists. Our leaders are choosing to ignore it.