Something led to the recent sudden deaths of a family of three and their dog on a hiking trail in the Sierra National Forest of Northern California, but what, exactly, is still unknown. Authorities said Thursday that it’s unlikely nearby mines played any role, but they do suspect that a toxic algae bloom could be to blame.
On Tuesday, the Mariposa County Sheriff’s Office reported the deaths of married couple John Gerrish and Ellen Chung, their 1-year-old daughter, Miju, and their dog. The group had been reported missing Monday evening by a friend. Their bodies were found on a hiking trail in an isolated area of the forest, some distance away from their vehicle. There was no clear indication of what killed them, authorities said, such as signs of bodily trauma or a suicide note. But the trail was near some closed-down mines, leaving open the possibility that the family was exposed to toxic gases. Initially, authorities decided to treat the area as a hazmat site.
By Wednesday, though, the hazmat warning was lifted and the mines are no longer considered a leading suspect for these deaths.
“I don’t believe it’s connected to a mine,” Mariposa County Sheriff Jeremy Briese told the Fresno Bee on Thursday.
On the short list of potential culprits, authorities have said, is a toxic algae bloom. Algae blooms happen when populations of algae in a body of water (fresh or salt) rapidly become massive, often due to warm weather and other conditions. This population boom can wreak havoc on the surrounding wildlife, and some algae species are also capable of pumping out large quantities of toxins as they swell. Most of the time, the greatest harm to humans comes from swimming in contaminated water or eating contaminated animals, but there is evidence that some toxins can briefly become airborne under the right circumstances. Like many health hazards, climate change has and is expected to make these blooms more common and more intense in certain parts of the world, including in the U.S.
In freshwater, blooms tend to be caused by blue-green algae, which are plant-like bacteria that rely on sunlight for nourishment. Small animals, including dogs, are more susceptible to dying from these blooms, but they are thought to be capable of killing humans. Symptoms vary depending on the specific toxin, but can include vomiting, diarrhoea, headaches, and other neurological symptoms.
Officials have now started testing nearby water sources for the presence of these blooms, while the family members were set to undergo an autopsy and toxicology tests on Thursday. “We don’t know the cause…We won’t rest until we figure it out,” Briese told the Fresno Bee.