The use of morphometrics in entomological surveillance of sylvatic foci of Triatoma infestans in Bolivia

Dujardin JP, Bermúdez H, Schofield CJ

    Jamach´uma (Cochabamba, Bolivia) is a small village surrounded by sylvatic foci of Triatoma infestans. Houses in the village were also infected with T. infestans, and were sprayed in December 1992 as part of a Chagas disease vector control trial. Ten months later the houses were found to be again infested with a few fifth instar nymphs of T. infestans. These nymphs were compared by seven head measurements with 36 fifth instar nymphs collected from houses in Jamach´uma before treatment, and with two sets of nymphs originating from the surrounding sylvatic foci: eight specimens collected in 1992 and nine specimens collected in 1995. The results are discussed in relation to the possible mechanisms of the apparent reinfestation: recrudescence of a residual domestic population or reinvasion of the houses from surrounding sylvatic foci. Quantitative comparisons support the former hypothesis.