The Venice Canals Association announced the deaths on Instagram, saying dogs have been vomiting, having seizures and collapsing.

Several dogs have died in the past 10 days in the Venice area due to an unknown cause, the Venice Canal Association said in a social media post. At least five “healthy neighborhood dogs” died and another is in the ICU with symptoms including: Vomiting Sudden weakness or lethargy Seizures cardiac arrest Collapse Foaming at the mouth Although the cause of these symptoms and the canines’ deaths are not confirmed,

Environmental officials are testing the waters in the Venice Canals after six dogs have died and more than a dozen others have gotten sick after walks near the canals.