No, a single bite or indeed any injury can result in either a criminal prosecution under Section 3(1) of the Dangerous Dogs Act, 1991, (if the incident occurs in a public place) or as a civil complaint under Section 2 of the Dogs Act (where the incident can have occurred on public or on private property). There is also a provision under the Dangerous Dogs Act for the person in charge of the dog at the time to be prosecuted, not just the owner of the dog.
Under Section 3(1) of the Dangerous Dogs Act the police have the discretionary power to seize a dog; however this does not mean they will necessarily do so. It will often depend upon the nature of the injuries, whether there have been any previous incidents with your dog or whether the police feel he poses a danger to the public. However, under the civil Dogs Act of 1871, the police do not have the power to seize a dog which is subject to complaint.