The addition of “host” blood to the replicated samples is important to the process, both for realism and for the creation of a physical DNA pellet required during the manual DNA extraction technique used here. If we used only trypanosomes in media, there would not be sufficient DNA in the solution to create this pellet and the target DNA would have been lost during the DNA extraction protocol. It also adds a more practical aspect to the experiment, as trypanosome detection is usually required from either whole blood or tissue samples, which contain host DNA in excess.