New bacteria found in stranded Florida pygmy sperm whales
Scientists identify three unknown strains linked to stomach disease in the elusive marine mammals.
Pygmy sperm whales are elusive, deep-diving marine mammals that are rarely observed alive, so much of what scientists know about them comes from stranded individuals – particularly along the southeastern U.S. In a new study published in the Journal of Wildlife Diseases, FAU Harbor Branch Oceanographic Institute researchers analyzed more than two decades of stranding data and discovered three previously unknown genotypes of Helicobacter bacteria in the whales’ stomach tissues. These newly identified strains, named Kogia Helicobacter 1, 2 and 3, mark the first documented occurrence of these specific bacteria in pygmy sperm whales.
By examining tissue samples from stranded whales between 1999 and 2020, scientists used histopathology, molecular diagnostics, and DNA sequencing to detect spiral-shaped bacteria associated with visible gastric disease, including ulcers, inflammation and fibrosis. While Helicobacter was not determined to be the direct cause of death in the affected whales, all infected individuals showed signs of gastrointestinal damage, raising questions about the bacteria’s role in long-term health. The findings expand scientific understanding of this little-known species and highlight how much remains undiscovered about microbial life in the ocean and its potential impact on marine mammal populations.
“This research underscores the value of long-term marine mammal stranding response programs,” said Annie Page, D.V.M., Ph.D., senior author, an associate research professor and clinical veterinarian at FAU Harbor Branch. “Without the ability to study these stranded animals over decades, we never would have discovered these bacteria. Every whale tells a story, and sometimes that story leads us into entirely new scientific territory.”