Frequency of minimum number of Trypanosoma cruzi clones detected in T. infestans midguts by three microsatellite markers in population samples from the III, V and M regions. The markers used were SCLE10, SCLE11 and MCLE01, previously described (Oliveira et al., 1998). The population samples included 15, 37 and 12 triatomine insects from the III, V and M regions, respectively (see the section on ‘Materials and methods’).