Pet owners warned as toxic algae blooms rise 40% in U.S.

Diving into cool water can be a quick way to escape the summer heat, but during certain times of year, freshwater can pose hidden dangers to people and pets. A growing number of veterinarians are reporting cases of dogs that have developed severe illness after swimming in lakes and ponds that contain toxic algae blooms. The toxins produced by cyanobacteria—often called blue‑green algae—can cause vomiting, diarrhea, tremors and, in extreme cases, liver failure or death.

The problem has been amplified by climate change. Warmer temperatures, longer growing seasons and increased rainfall create ideal conditions for cyanobacteria to thrive. In the United States, the National Oceanic and Atmospheric Administration has logged a 40 % rise in harmful algal blooms over the past decade. Because the toxins are dissolved in the water, they can be invisible even when the bloom looks harmless. Dogs are especially vulnerable because they tend to drink and lick water, ingesting larger volumes than humans would normally.

In 2023, the American Veterinary Medical Association recorded more than 180 cases of canine cyanobacterial intoxication across 15 states. Symptoms appeared within hours of exposure and ranged from mild gastrointestinal upset to acute liver failure requiring emergency care. Several state wildlife agencies have closed popular lakes during peak bloom periods, and the U.S. Environmental Protection Agency now recommends that pet owners avoid letting dogs swim in water that has a greenish surface, a foul odor or a scummy film. Some local authorities have even issued advisories that warn owners to test water with rapid kits before allowing pets to play.

Pet owners can protect their dogs by staying informed. Check local