For comparison we measured the stability of expression i) of the tRG class gene Hprt still being widely used in parasitic infections studies [36], ii) of the B1 and B2 elements belonging to the short interspersed nuclear element (SINE) family and representing the rRG class and iii) of the uRG class members Rps29, Rpl4 and Oaz1[24]). The gene discussed is HPRT1; the disease is parasitic infectious disease.