Boletín chileno de parasitología
versión impresa ISSN 0365-9402
SCHENONE, Hugo; ROJAS MERCADO, Antonio y CASTILLO, Douglas. Comparative study on sensivity and mortality of Triatoma infestans nymphs III and IV used in the xenodiagnosis of chronic chagasic patients. Bol. chil. parasitol. [online]. 2000, vol.55, n.1-2, pp. 14-17. ISSN 0365-9402. doi: 10.4067/S0365-94022000000100004.
Triatoma infestans nymphs have shown a good sensitivity for detecting Trypanosoma cruzi in the blood stream of infected hosts when are used in the xenodiagnosis (XD). This method, with its natural limitations, using seven nymphs III of T. infestans, has been routinely utilized with satisfactory yield. With the aim of an eventual improving of the yiel of XD (with 7 nymphs), two series of 54 XD boxes each, containing a total of 378 nymphs III and 378 nymphs IV respectively, were applied - one of each during three consecutive days - to nine chronic chagasic patients. Each of the nymphs was weighted before and after the application of the boxes, and the intestinal content of them was examined 30 , 60 and 90 days later. The main comparative results obtained with nymphs III and IV of T. infestans were: blood ingestion 40 versus 107 mg (2.7 higher), positivity of insects 35.8% versus 50.6% (15.8% higher), positivity of XD boxes (7 nymphs each)46.3% versus 55.6% (9.3% higher), and mortality rates 28,6% versus 12.2% (16.4% lower). All these results demonstrate that nymphs IV of T. infestans, because their higher capacity of ingesting blood and higher tolerance to examination manipulations, are more suitable for been used in XD.
Palabras clave : xenodiagnosis; sensitivity; nymphs; chronic chagasic patients.