This spring, the avian influenza, or bird flu, was found in two cetaceans in two entirely different parts of the world. The first was an infection in a stranded porpoise in Sweden, and the second was in a bottlenose dolphin in a Florida canal. While this disease has been recognized for spreading amongst North American and European bird populations, it still affects other species. However, these are the first records of it being found in cetaceans, another name for marine mammals like whales, dolphins, and porpoises.
It’s unknown how common the disease is among cetaceans. But scientists believe that the cases being in two different species across the world from each other makes it a near certainty many other cetaceans carry the disease. It’s not much of a shock that such an infectious disease would appear in other species, but it suggests that the virus could cause even more problems in the future.
Experts acknowledge that the risk of human infection is still low. However, the virus spreading to other species gives it more opportunities to adapt and mutate to affect new hosts, which could include other mammals like humans. This spring’s outbreak, Eurasian H5N1, has affected millions of farmed birds but has been particularly harrowing for wild bird populations. Because of this, animals like foxes or bobcats who come in contact with wild birds are beginning to contract the disease.
The infected dolphin was found after area residents noticed the animal had been trapped in a canal in Dixie County. The marine animal rescue program at the University of Florida responded to the call, but by the time anyone arrived, the dolphin had died.
The team collected various samples from the dolphin for analysis, never once suspecting they would find bird flu. The lab results indicated Eurasian H5N1 in the dolphin’s brain and lungs, with a high concentration of the virus in the brain tissue. It’s unclear whether or not the virus contributed to the dolphin’s death.
In contrast, the virus found in the porpoise in Sweden did contribute directly to its death. The Swedish National Veterinary Institute confirmed it, and, like with the Florida bottlenose dolphin, the pathogen was found in multiple organs, including the porpoise’s brain.
Now that scientists are taking a closer look, they’re noticing that the virus still looks like one you would find in an infected bird. So there are no telltale signs that the virus has mutated to adapt to mammals, despite the infections. But the findings have put many on high alert. There’s now a concerted effort to help protect cetaceans from the pathogen, as well as to understand how serious it is for them – and what it could mean for our future with the bird flu.
Written for Passport Health by CJ Darnieder. CJ is a freelance writer and editor in Chicago. He is an avid lover of classical music and stand-up comedy and loves to write both in his spare time.