Secondary infection
Parasites for the secondary infection were obtained as described
above in the section “Parasite population”, this time however; the
parasites were obtained from infected guppies (Poecilia reticulata).
Five hundred degree days or 21 days following the first infection 8
survivor fish were re-infected with 5000 theronts/fish. The fish were
infected by adding 80 mL water with 500 theronts/mL to the tank.
Twenty-four h post the secondary infection the fish received a
complete water change. From here on the fish were fed with dry feed
and received a 50% water change every day. Ten naive transparent
and 10 naive wildtype (wt) zebrafish were furthermore infected with
the same amount of parasites using the same procedure.