Infections
An infection is the colonization of a host organism by a foreign organism. The infecting organism seeks to utilize the host’s resources to multiply.
The infecting organism, or pathogen, interferes with the normal functioning of the host. Its response is inflammation.
Many individuals develop a variety of infections but quickly overcome them. Some develop persistent infections, which are mostly caused by viruses and not bacteria.
An infectious disease can be transmitted by a parasite. Parasitic diseases can affect almost all living organisms. Some parasites like Toxoplasma gondii can cause disease directly, but other organisms can cause a disease by the toxins that they produce.
