Interactions between a virus and its host, i.e. man in the case of viruses of a medical interest, take place at different levels. On the host cell level, multiple molecular interactions between viral and cellular structures are necessary for the virus to enter a cell, to replicate in it, and to leave it again in order to infect new target cells.
On the level of the infected individual, an invading virus enters the body at different entry ports. It has to overcome the antiviral defense systems of the host, which may individually differ in their effectiveness, in order to infect and replicate in suitable target cells. But viruses also make use of the host's transport systems, such as the vascular system, the lymphatics, or the nervous system, in order to spread in the body and to infect target organs more distant to the entry port.
On a still higher level of interaction, that of the infected host population, i.e., mankind, viruses exert an influence on the composition of the human population. Some individuals may have a genetic background which protects them better against a viral infection. Alternatively, even persons without such innate protection can protect themselves actively against getting infected, for example by avoiding exposure, using barrier methods, or taking antiviral drugs. Protected individuals have a better chance of surviving a viral epidemic. Conversely, the host population also influences the composition of the infecting viral population. Viruses may mutate and thus become resistant to the host's defense systems or antiviral drugs, rendering them ineffective. Such resistant viruses may become more frequent and thus become an even higher threat to mankind.
The Institute's research addresses all three levels. Our focus of interest is on human immuodeficiency viruses (HIV) and influenza virus. .