Aetiological treatment of congenital Chagas' disease diagnosed and monitored by the polymerase chain reaction.
OBJECTIVE
This prospective study focused on the evaluation of anti-parasitic therapy in congenital Chagas' disease, diagnosed and monitored by PCR and conventional diagnosis.


METHODS
We studied 152 children born to seroreactive mothers, living in a non-endemic area. Fifty infants aged 0-6 months (GA) were diagnosed by microhaematocrit and PCR and 102 children aged 7 months to 17 years (GB) were diagnosed by serology and PCR. Forty treated patients were monitored for 2 or 3 years by PCR and conventional methods. A competitive-quantitative PCR was used to determine pre-therapy parasitic loads and follow their post-treatment evolution.


RESULTS
In GA, the sensitivities of the PCR and microhaematocrit were 100% and 82.4% and their specificities 97% and 100%, respectively. In GB, the sensitivity of the PCR was 73.8% with a specificity of 100%. Pre-therapy parasitic loads ranged from 12.5 to 125,000 and 12.5 to 125 parasite genomic equivalents/mL of blood in GA and GB, respectively. PCR turned negative in all treated pre-therapy PCR positive patients before or at the end of treatment, which was followed by their seronegativation in 10/10 GA, in 3/5 children initiating therapy at 7 months to 2 years of age but in 0/16 initiating therapy at an older age. Two out of the latter patients were occasionally PCR positive during post-treatment, suggesting no parasitological response. Out of nine pre-therapy PCR negative patients, four turned seronegative after treatment, suggesting that in undetermined patients, undetectable parasitic burdens may lead to better post-treatment prognosis.


CONCLUSIONS
PCR was useful for sensitive diagnosis and therapy monitoring, allowing early detection of refractory cases.
Schijman
Alejandro G
AG
Laboratorio de Biología Molecular de la Enfermedad de Chagas, Instituto de Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina. schijman@dna.uba.ar
Altcheh
Jaime
J
Burgos
Juan M
JM
Biancardi
Miguel
M
Bisio
Margarita
M
Levin
Mariano J
MJ
Freilij
Héctor
H
D000293:Adolescent; D000818:Animals; D000977:Antiparasitic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001118:Argentina; D014355:Chagas Disease / Q000175:diagnosis* / Q000188:drug therapy* / Q000469:parasitology; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers; D016054:DNA, Protozoan / Q000096:biosynthesis / Q000235:genetics; D004996:Ethidium; D005260:Female; D005500:Follow-Up Studies; D006400:Hematocrit; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008991:Monitoring, Physiologic; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012698:Serologic Tests; D014349:Trypanosoma cruzi / Q000235:genetics
D000977:Antiparasitic Agents; D017931:DNA Primers; D016054:DNA, Protozoan; D004996:Ethidium