Companion animals today have the opportunity to live longer, healthier lives than ever before. One of the main reasons for this is the availability of vaccines that can protect pets from deadly infectious diseases. Over the past several decades, the widespread use of vaccines against diseases like panleukopenia and rabies has saved the lives of millions of cats. Unfortunately, infectious diseases still pose a significant threat to cats that are unvaccinated; so, although vaccine programs have been highly successful, pet owners and veterinarians cannot afford to become complacent about the importance of keeping pets up-to-date on their vaccinations.