Whether illness results or not depends on the immunity present in the victim vs. the number of individual virus particles (i.e. the amount of virus) entering the body. (marvistavet.com)
Whether illness results or not depends on the immunity in the victim vs. the number of individual virus particles (i.e. the amount of virus) entering the body. (vin.com)
The researchers tagged individual viruses with one or two fluorescent molecules, each of which is about 1/25 the size of the virus. (sciencemag.org)