It is the invasion of the body by organisms that infect, multiply and cause disease in the body. Infections can be caused by bacteria, virus, viroids, nematodes, worms, ticks, mites, fungus, tapeworms and many more. The body protects itself from infection using its immune system. An infection usually manifests as fever, inflammation, rashes etc. Depending on the type of infection a doctor may prescribe antibiotics, creams or steroids in case of severe infections.