Guests Who Are a Little Too Relaxed
They’re here, they’re spreading, and so far, they haven’t triggered a global emergency. Yet two viruses of animal origin are starting to get a little too comfortable in close proximity to humans. That’s the conclusion reached by infectious disease experts in a recent review of studies. According to them, all the ingredients for a future epidemic are in place: frequent contact with animals, insufficient testing, and a frankly inadequate system for the early detection of new respiratory viruses.
Which viruses are we talking about? Influenza D and canine coronavirus. These researchers assert that they deserve far more attention than they are currently receiving. The concern isn’t just that they can already infect people. The real fear is how they might evolve. If either one learns to spread effectively from person to person, it could sweep through the population at lightning speed. Why? Simply because we have virtually no existing immunity against them.
Influenza D: The One That Creeps Up on You
Why isn’t anyone sounding the alarm louder? Because these viruses are masters of discretion. Take Influenza D. First identified in 2011, it was thought to primarily affect pigs and cattle. Since then, it has been found in a wide variety of animals: poultry, deer, giraffes, and even kangaroos. In cows, it contributes to bovine respiratory disease, a costly problem that impacts livestock health and farm productivity.
But what is intriguing—and concerning—is what is happening at the interface between humans and animals. Studies conducted among livestock farmers in Colorado and Florida revealed a staggering figure: up to 97% of people working with herds had antibodies to influenza D. Having antibodies doesn’t mean you’re sick at that exact moment, but it proves you’ve come into contact with the virus.
For now, these exposures appear to be “subclinical.” What does that mean? People are infected but don’t experience any symptoms. This may seem reassuring, but it’s a double-edged sword. A virus that spreads silently can spread widely without being detected. John Lednicky, a professor at the University of Florida, points out: “Our review of the literature indicates that these two viruses pose respiratory disease threats to humans, yet little has been done to respond to or prevent infection.” Worse still, influenza D is evolving rapidly. A strain recently isolated in China has already developed the ability to spread between humans. It’s exactly this kind of mutation that elevates a virus from “curious” to “urgent.”
The canine coronavirus: when man’s best friend coughs
Let’s move on to the second candidate: the canine coronavirus (CCoV). Note that this has nothing to do with the SARS-CoV-2 virus that causes COVID-19. In dogs, this virus is best known for causing gastrointestinal disorders. But in humans, the story is different. Scientists are now taking a very close look at it because they’ve linked rare human infections to hospitalizations for pneumonia in Southeast Asia.
The problem is the statistical blind spot. “Diagnostic tests aren’t routinely performed for this virus, so we don’t know to what extent it affects the general population,” explains John Lednicky. If doctors aren’t looking for it, cases don’t show up in the data. And without data, the virus flies under the radar for years.
The fact that it is found in so many places suggests that it has already crossed regional borders. This does not mean that it spreads easily between humans—travel and repeated contact with animals may explain these scattered cases—but its recurrence is a warning sign that warrants closer monitoring.
Don’t wait until your back is against the wall
The central message of this study, published in the journal Emerging Infectious Diseases, is crystal clear: we cannot afford to wait until a virus has fully established human-to-human transmission before we start paying attention to it. The current lack of knowledge is a risk in itself. “Our knowledge of the epidemiology and clinical manifestations of these viruses is limited to a modest number of research studies,” the authors write. But even these limited data indicate that they pose a “major threat to public health.”
So, what should be done? The plan is simple: strengthen surveillance in animals and humans, and develop diagnostic tools that doctors will actually use. We must also start planning now for treatments—and even vaccines—rather than waiting for a crisis to force our hand. This is not about giving in to panic, but about understanding that complacency comes at a high cost. These viruses are already sending warning signals—from antibodies in farmworkers to sporadic cases of pneumonia around the world. The very essence of preparedness is to treat these signals as a reason to investigate further, not to shrug them off.
Source: earth.com
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These Two Little-Known Viruses That Could Very Well Pave the Way for the Next Health Crisis
