Clinical Infectious diseases are caused by microorganisms like fungi, bacteria, viruses and even parasites. They’re contagious and transmitted by insects, animals and by taking contaminated food and water. Chickenpox, measles, enteric fever, etc. a number of the infectious diseases conjointly cause cancer like Human papillomavirus causes cervical cancer; cancer caused by infection of EBV. These infectious diseases are clinically diagnosed by laboratory tests like blood tests, weewee tests, spinal puncture, throat swabs, CT, resonance imaging, and other studies.