[A modified Strout test, used as a probe for the diagnosis of transplacental Chagas disease. I. Collection and preservation of the newborn's umbilical cord blood].

Source: PubMed, NCBI / U.S. National Library of Medicine

Two umbilical cord (UC) blood samples are routinarily taken from each newborn (NB) at the University of Chile Maternity Hospital, to determine blood grouping and for detecting syphilis infection respectively. In august-september 1993, an additional UC blood sample was collected from each of 116 NB (with volumes of whole blood ranging 2.7 - 24.5 ml and a mean of 13.5 ml). In order to determine the persistence of the mobility of Trypanosoma cruzi in blood samples stored at three different temperatures (-2 to -4 degrees C, 4 to 6 degrees C and environmental temperature from 16 to 23 degrees C), two experiments were performed: 1) In three centrifuge microtubes mouse blood (C3H strain) abundant T. cruzi trypomastigotes Tulahuen strain were put. 2) In an other similar number of microtubes, with the same concentration of parasites, human serum from UC was added. During the first 12 h in all the samples trypomastigotes with very active mobility were observed. At 72 h mobility persisted in samples with temperature between 4 and 6 degrees C and between 16 and 23 degrees C. Whereas in the samples maintained at -2 to -4 degrees C with parasites in blood plus serum, an important decrease of T. cruzi mobility was observed. The results of this study suggest that UC blood samples could be collected and maintained between 4 and 6 degrees C or at room temperature up to 48 h to be processed by the modified Strout concentration method (MSCM).(ABSTRACT TRUNCATED AT 250 WORDS)