Here's why we can assume Italian wizards exist:
* The wizarding world is international: We see wizards and witches from various countries throughout the series, including France, Germany, and even Bulgaria. It's likely Italy, a country with a long and rich history, would have its own wizarding community.
* The Ministry of Magic has international connections: The Ministry of Magic in Britain has diplomatic relations with other magical governments. It's reasonable to assume Italy would have its own Ministry or equivalent organization.
* Magical creatures are found worldwide: We encounter magical creatures like merpeople, werewolves, and goblins in various countries. It's plausible that Italy, with its diverse landscape and rich folklore, would have its own unique magical creatures.
While we don't know specific Italian wizards, their existence within the Harry Potter universe is a strong possibility.