A simple method to identify Triatomine (Hemiptera: Reduviidae) feces in sensing devices used in vector surveillance programs

GURTLER RE; ONETO ML; CECERE MC; CASTAÑERA MB; CANALE MD

JOURNAL OF MEDICAL ENTOMOLOGY

Año: 2001 vol. 38 p. 147 - 152

0022-2585

We successfully applied the phenolphthalin (KastleÐMeyer) test used in forensic chemistry to distinguish between feces from triatomines and other domestic arthropods in sensing devices used for vector surveillance. All black or dark brown, but not white or yellow, fecal smears from laboratory-reared or Þeld-collected Triatoma infestans Klug, Triatoma guasayana Wydgozinsky & Abalos, Triatoma sordida Ståhl (recently revalidated as Triatoma garciabesi Carcavallo, Cichero, Martõ´nez, Prosen & Ronderos) tested positive, whereas dejecta from cockroaches and spiders, crickets, beetles, predatory bugs, and domestic ßies tested negative. Black or dark brown dejecta from female Aedes aegypti L. and Cimex lectularius L. bedbugs also tested positive. In sensing devices installed in bedrooms of 11 houses in Amama´, rural northwestern Argentina, where neither cimicid bedbugs nor argasid ticks had been found over the years, only 62% of the black or dark brown fecal smears attributed to triatomines by a skilled observer tested phenolphthalin-positive. After insecticidal spraying, when bedroom areas were not colonized by triatomines, only 33Ð40% of the black or dark brown fecal smears in sensor boxes attributed to triatomines by another skilled observer tested phenolphthalin-positive. Eleven (79%) of the 14 houses with dubious or nontypical triatomine feces tested phenolphthalin-positive at least once during 1993Ð1995. Our study introduces a low-cost, simple and effective procedure for the identiÞcation of triatomine feces. The test, as a helpful adjunct to sensing devices used in triatomine surveillance, will aid in the accurate detection of infestations and the determination of the need for insecticide application.Triatoma infestans Klug, Triatoma guasayana Wydgozinsky & Abalos, Triatoma sordida Ståhl (recently revalidated as Triatoma garciabesi Carcavallo, Cichero, Martõ´nez, Prosen & Ronderos) tested positive, whereas dejecta from cockroaches and spiders, crickets, beetles, predatory bugs, and domestic ßies tested negative. Black or dark brown dejecta from female Aedes aegypti L. and Cimex lectularius L. bedbugs also tested positive. In sensing devices installed in bedrooms of 11 houses in Amama´, rural northwestern Argentina, where neither cimicid bedbugs nor argasid ticks had been found over the years, only 62% of the black or dark brown fecal smears attributed to triatomines by a skilled observer tested phenolphthalin-positive. After insecticidal spraying, when bedroom areas were not colonized by triatomines, only 33Ð40% of the black or dark brown fecal smears in sensor boxes attributed to triatomines by another skilled observer tested phenolphthalin-positive. Eleven (79%) of the 14 houses with dubious or nontypical triatomine feces tested phenolphthalin-positive at least once during 1993Ð1995. Our study introduces a low-cost, simple and effective procedure for the identiÞcation of triatomine feces. The test, as a helpful adjunct to sensing devices used in triatomine surveillance, will aid in the accurate detection of infestations and the determination of the need for insecticide application. KEY WORDS Triatoma infestans, Triatoma guasayana, Triatoma sordida, Chagas disease, surveillance, sampling sampling