The Arizona Department of Agriculture is warning pet owners about the deadly bacteria: Leptospirosis.
It's spread through bodily fluids like urine and humans can catch the bacteria, too. Normally the Valley sees about four cases a year. At this point, there are more than 40 confirmed cases in dogs.
The bacteria can live for months in wet soil which is why the Valley normally doesn't see many cases with its dry conditions. Health officials aren't pinpointing where the infections started in the Valley but they are warning pet owners to be cautious with doggy daycare and dog parks.
Pets will usually show symptoms when they are sick with the bacteria. Veterinarians say dogs will be tired, probably won't eat and drink a lot of water. The disease is treated by antibiotics but could be deadly if left untreated.
Scottsdale is the hardest hit city with other cases in Phoenix, Gilbert, Tempe, Litchfield Park, Fountain Hills and Avondale.