Infection is the process of invasive microorganisms attacking the body tissue causing an infectious disease. Infections can be acute, chronic or latent. An acute infection rapidly progresses needing urgent care and is normally short lived whereas a chronic disease is normally a virus infection which has progressed over time and has lasted for more than three months. Latent infection sits dormant and hidden until triggered. The severity of the infection can be determined by the invasion depending if viral, bacterial, autoimmune or idiopathic. A viral disease is the tiniest microbe with a protein coat, RNA and DNA genetic material that cannot live without a host cell. Viral infections cause a disease to specific cells like the liver, respiratory or blood for example. Bacterial infections tend to spread from person to person and are highly contagious, precautionary measure need to be taken when in contact with someone with a bacterial infection. Autoimmune disease attacks the healthy cells within the immune system and idiopathic is an unknown cause. Infections can be spread in many ways and cause different severity to the body. With proper hygiene such as washing hands, cough, and respiratory etiquette microbes have a less chance of growing and infecting the body tissue.