A 30-year-old patient complains of pain and swelling in the area of the left parotid salivary gland, which occurred 7 days after he had undergone abdominal cavity surgery. Objectively: body temperature is 39°C, reduced mouth opening, dry mouth; when the gland is massaged, there is purulent exudate being secreted from its duct. The patient can be diagnosed with the following disease: