Firstly, although both IgG and IgM antibodies are commonly studied in seroepidemiology of T. gondii studies, in this study the IgM measurement was excluded for three reasons as follows: (1) financial resource constraints, (2) the aim of the study which was to estimate the epidemiology of T. gondii in Markazi Province and not to diagnose and treat it, (3) detection of IgG but not IgM against T. gondii infection defines the classical serologic pattern of latent infection. The gene discussed is CD40LG; the disease is disease arising from reactivation of latent virus.