Dipetalogaster maximus (Hemiptera, Triatominae) for xenodiagnosis of patients with serologically detectable Trypanosoma cruzi infection.

In patients serologically positive for Trypanosoma cruzi infection the three bug species/instar combinations used in xenodiagnosis showed third-instar Dipetalogaster maximus to be more efficient in detecting circulating trypanosomes than the first instar of the same species which, in turn, is more sensitive than third-instar Triatoma infestans. The sensitivity of the pool technique of faecal examination compared with individual dissection was investigated. Four pool examinations (the product of 20 bugs) were equivalent to 10 individual bug dissections. Because of the ease of providing large numbers of bugs for mass xenodiagnosis, first-instar D. maximus has replaced third-instar T. infestans in our routine work. The value of third-instar D. maximus as a xenodiagnostic agent needs further investigation.