1) Infectious disease 
In parasitology, coinfection ən is the simultaneous infection of a host by multiple pathogen species. In virology, coinfection includes simultaneous infection of a single cell by two or more virus particles. An example is the coinfection of liver cells with Hepatitis B virus and Hepatitis D virus, which can arise incrementally by initial infectio...
(ko´in-fek″shәn) simultaneous infection by separate pathogens, as by hepatitis B and hepatitis D viruses.
concurrent infection with more than one disease-causing organism (e.g., HCV and HIV).
Simultaneous infection with two or more different diseases. In virology the term is used to describe