The technically distinct terms "Transfection" and"Transduction" are very loosely used throughout the manuscript.Please note that when nucleic acids are introduced to cells through viral infection, the method is referred as transduction.
Wikipedia (http://en.wikipedia.org/wiki/Cell_culture#Transfection_and_transduction)より
Transfection and transduction
Another common method for manipulating cells involves the introduction of foreign DNA by transfection. This is often performed to cause cells to express a protein of interest. More recently, the transfection of RNAi constructs have been realized as a convenient mechanism for suppressing the expression of a particular gene/protein. DNA can also be inserted into cells using viruses, in methods referred to as transduction, infection or transformation. Viruses, as parasitic agents, are well suited to introducing DNA into cells, as this is a part of their normal course of reproduction.