Int. J. Environ. Res. Public Health 2010, 7 956 Figure 11. Probable mechanisms of the magnetic field influence on gene expression and virus-host interactions. MAGNETIC FIELD Cryptochromes CLOCK/BMAL1 + CBP Circadian genes expression Circadian control of stress and other “non- circadian” responses by active transcriptional repression mechanism membrane potential ion channels function Ca2+ signaling Ion resonance effects Ca2+-Operated Transcriptional Networks Expression and function of proteins of NF-kB signaling pathway Immunity regulation Regulation flu RNA synthesis Regulation of virus-host interactions and other biological processes We believe that the data we have presented concerning the probable influence of specific external magnetic fields on immunological processes and virus replication via the NF-κB and other signaling pathways allows us to put forward a possible role of geomagnetic field fluctuations, and correspondingly, solar activity cycles as factors capable of influencing the occurrence of influenza (and possibly other) epidemics. It is worth mentioning that several viruses, including HIV, have binding sites for NF-κB that control the expression of viral genes, which in turn contribute to viral replication and/or pathogenicity. In the case of HIV-1, activation of NF-κB may, at least in part, be involved in activation of the virus from a latent, inactive state [111]. This indicates the theoretical possibility of magnetic field effects on the processes of HIV activation and replication.