Many human illnesses are caused by infection with either bacteria or viruses. Antibiotic-resistant strains are beginning to appear, although for the most part, antibiotics are still effective in treating bacterial infections. viruses hide inside cells, they pose a threat to the immune system of the body. It is feasible to receive vaccinations against a few of the main viruses that cause sickness. This book is focused on Bacterial and Viral pathogenecity, prevention and treatment.