Treatment of Trypanosoma cruzi-infected children with nifurtimox: a 3 year follow-up by PCR

Abstract

Patients suffering from Chagas' disease, as determined by positive serological results, were tested for further evidence of Trypanosoma cruzi infection by xenodiagnosis and PCR. The patients included 67 children aged from 0 to 10 years and 75 adults. All children were positive by PCR on their pre-therapy sample, while only 69% of the seropositive adults and none of the 78 seronegative control adults were PCR positive. Xenodiagnosis was positive in 79% of the children, but only in 21% of the adults. A group of 66 children was treated with nifurtimox, and followed up every 3 months during the first year and every 6 months during the second and third year post-therapy, by PCR, xenodiagnosis and serology. We concluded that PCR was the most effective test to monitor children for 3 years post-chemotherapy, when all the cases converted from positive to negative. Conventional serology, however, remained positive after that period in most cases. In contrast, conversion to negative xenodiagnosis occurred very early after treatment.

Monitoring the efficacy of specific treatment in chronic Chagas disease by polymerase chain reaction and flow cytometry analysis

“…The 330 bp fragment of the kinetoplast minicircles is normally used as a target for amplification. The PCR assays have shown a variable degree of efficiency, thus a negative result does not necessarily mean that the individual is free of infection because the volume of sample can be insufficient (Solari, 2001). Chiari (1999), reported that an optimized PCR protocol is well correlated with detection of antibodies that induce lysis in trypomastigote forms (CoML) in the presence of complement, indicating active infection in those patients.…”

“…DNA was resuspended in 50 µl of water, chromatographed in a P10 filtration microcolumn and stored at -20º C. PCR reactions were performed as described by Solari et al (2001). Briefly, 5 µl of template DNA was amplified in a final volume of 50 µl containing 0.25 mM of each dATP, dCTP, dGTP and dTTP, 200 ng of forward and reverse T. cruzi specific primers 121 (5'-AAATAATG-TACGGG (T/G) GAGATGCATGA3') and 122 (5' GGTTC-GATTGGGGTTGGTGTAATATA3'), 2.5 U of Taq polymerase, 5 µl of 10 × Taq DNA polymerase buffer and 6.7 mM MgCl 2 .…”

“…Also, the polymerase chain reaction (PCR), has been T he disparity in trypanocidal action of available drugs as well as their negative side effects have prompted a search for new compounds with low toxicity and increased efficacy during the chronic phase of Chagas disease (Rodríguez et al, 2002). One of the major challenges regarding the evaluation of treatment effectiveness is the lack of reliable laboratorial approaches for use as tools for cure criteria (Chiari, 1999 used to detect T. cruzi in the blood of chronic chagasic patients (Britto et al, 1995(Britto et al, , 2001Solari et al, 2001). Recently, a strong correlation was reported between positive PCR and the presence of lytic antibodies among chagasic patients, suggesting that PCR could be effective in evaluating parasitological cure in patients who received a specific treatment (Zulantay et al, 2004).…”

Ergosterol biosynthesis and drug development for Chagas disease

“…Moreover, it has been reported in the last 15 years that BZN also exhibits significant curative activity in those with recent onset (up to a few years) of chronic disease; 60-70% of radical parasitological cures have been observed among children up to 14 years of age in Brazil and Argentina (de Andrade et al 1996, Andrade & Zicker 1997, Sosa Estani et al 1998, Sosa Estani & Segura 1999, Andrade et al 2004). On the other hand, other studies in patients of the same age range treated with either BZN or NFX contradict these conclusions (Silveira et al 2000, Solari et al 2001.…”

Evaluation of the ELISA-F29 test as an early marker of therapeutic efficacy in adults with chronic Chagas disease

“…Furthermore, there has been an increase in the use of molecular methods for detecting T. cruzi in blood samples of treated patients 4,7,19,20 .…”