Abstract
Previously, we reported that Kagoshima, Japan, is an endemic area of canine silica urolithiasis. Tap water in Kagoshima contains significantly greater silica concentrations than other areas of Japan. Ingestion of silica from tap water may lead to the formation of silica uroliths in dogs. We measured the concentration of silica in tap water from various areas of Japan. Concentrations were higher in the city of Takeda（Oita prefecture） and in some areas around the city of Chikusei（Ibaraki prefecture）. Fast atom bombardment mass spectrometry analysis of water from Kirishima（Kagoshima prefecture）revealed that the character of water was similar to that after silica sintering. Removal of silica from tap water may decrease the risk of silica urolithiasis in dogs. We demonstrated that silica could be successfully removed from tap water with a reverse osmosis membrane water filter but not with a typical domestic water filter. We also sent internet-based questionnaires to owners of dogs with silica uroliths to investigate other possible etiologies of silica urolithiasis. The results revealed that the specific pet food brand may be related to silica urolithiasis. However, the concentration of total silica in pet food does not appear to be related to the formation of uroliths.
