PCR-based diagnosis for Chagas' disease in Bolivian children living in an active transmission area: comparison with conventional serological and parasitological diagnosis
P. WINCKER a1 a2 , J. TELLERIA a3 , M. F. BOSSENO a3 , M. A. CARDOSO a1 , P. MARQUES a1 , N. YAKSIC a4 , C. AZNAR a5 , P. LIEGEARD a5 , M. HONTEBEYRIE a5 , F. NOIREAU a6 , C. M. MOREL a1 and S. F. BRENIERE a3
a1 Laboratorio de Biologia Molecular e Doenças Endêmicas, Departmento de Bioquimica e Biologia Molecular, Instituto Oswaldo Cruz, Fundaçao Oswaldo Cruz, Av. Brasil 4365, 21045-900 Rio de Janeiro, Brazil
a2 Laboratoire Génome des Parasites, Parasitologie, Faculté de Médecine, 163 rue Auguste Broussonet, 34000 Montpellier, France
a3 UR41, UMR ORSTOM/CNRS 9926 “Génétique moléculaire des Parasites et des Vecteurs”, CP 9214, La Paz, Bolivia
a4 Universidad mayor de San Andres, IBBA, CP 641, La Paz, Bolivia
a5 Institut Pasteur, Département d'Immunologie et Centre de Biologie médicale, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
a6 UR 41 ORSTOM, C.P. 9214, La Paz, Bolivia
A large field study has been performed in the Cochabamba region of Bolivia with the aim of comparing the polymerase chain reaction (PCR) with other diagnostic methods for Chagas' disease. The amplification of Trypanosoma cruzi-specific kinetoplast DNA sequences in blood samples was compared with classical serological methods, specific IgM detection and direct parasite visualization for 268 school children in a single village where Chagas' disease transmission is active. Of 113 children positive by classical serology or buffy coat examination, 106 were detected by PCR (sensitivity: 93·8%). We did not observe any significant difference of PCR sensitivity between initial (IgM and/or buffy coat positive) and indeterminate stage (only IgG positive) patients. Among the remaining 155 children unconfirmed as chagasic (who were either only IgM positive, IgG-, IgM-, and buffy coat-negative) only 1 case was PCR positive. This case may be due to DNA contamination, or to a very recent infection not detected otherwise, or to specific immune depression. These results show that PCR is a very sensitive parasitological test for Chagas' disease in active transmission regions. The future follow-up of the possibly infected patients who were only IgM-positive should clarify the interest of PCR and IgM tests in the detection of starting infections.(Received July 9 1996)
(Revised September 30 1996)
(Accepted October 1 1996)
Key Words: Trypanosoma cruzi; Chagas' disease; PCR diagnosis; serological diagnosis.
Corresponding author: Laboratoire Génome des Parasites, Parasitologie-Faculté de Médecine, 163 rue Auguste Broussonet, 34000 Montpellier, France. Tel: +33 467 63 55 13. Fax: +33 467 63 00 49.