title: Parasite persistence in treated chagasic patients revealed by xenodiagnosis and polymerase chain reaction.
abstract: Polymerase chain reaction (PCR) was compared with xenodiagnosis performed 20 years after trypanocidal chemotherapy to investigate parasite clearance. Eighty-five seropositive individuals for Chagas disease presenting a positive xenodiagnosis were treated with specific drugs; 37 in the acute phase and 48 in the chronic phase. Fifteen chronic asymptomatic patients received a placebo. Treatment in the acute phase led to PCR negative results in 73% of the cases, while xenodiagnosis was negative in 86%. In the chronic phase, PCR was negative in 65% of the patients and 83% led to xenodiagnosis negative results. Regarding the untreated group (placebo), 73% gave negative results by xenodiagnosis, of which 36% were positive by PCR. Individuals that were considered seronegative (n=10), presented unequivocally negative results in the PCR demonstrating the elimination of parasite DNA. Seventeen individuals had their antibodies titers decreased to such a level that the final results were considered as doubtful and 16 of them presented negative PCR. The molecular method represents a clear advantage over conventional techniques to demonstrate persistent infections in Chagas disease patients that underwent chemotherapy.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz-Fiocruz, 21045-900 Rio de Janeiro, RJ, Brasil. cbritto@gene.dbbm.fiocruz.br
authors.forename: C
authors.initials: C
authors.lastname: Britto
authors.forename: C
authors.initials: C
authors.lastname: Silveira
authors.forename: M A
authors.initials: MA
authors.lastname: Cardoso
authors.forename: P
authors.initials: P
authors.lastname: Marques
authors.forename: A
authors.initials: A
authors.lastname: Luquetti
authors.forename: V
authors.initials: V
authors.lastname: Macêdo
authors.forename: O
authors.initials: O
authors.lastname: Fernandes
mesh_terms: D000208:Acute Disease; D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy / Q000469:parasitology*; D016009:Chi-Square Distribution; D002908:Chronic Disease; D018105:DNA, Kinetoplast / Q000032:analysis; D005500:Follow-Up Studies; D006801:Humans; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D014344:Trypanocidal Agents / Q000627:therapeutic use; D020525:Xenodiagnosis
chemical_list: D018105:DNA, Kinetoplast; D014344:Trypanocidal Agents