PCR-based screening and lineage identification of Trypanosoma cruzi directly from faecal samples of triatomine bugs from northwestern Argentina

P. L. MARCET a2, T. DUFFY a1, M. V. CARDINAL a2, J. M. BURGOS a1, M. A. LAURICELLA a3, M. J. LEVIN a1, U. KITRON a4, R. E. GÜRTLER a2 and A. G. SCHIJMAN a1c1
a1 Laboratorio de Biología Molecular de la Enfermedad de Chagas, Instituto de Ingeniería Genética y Biología Molecular (INGEBI-CONICET), Vuelta de Obligado 2490, 2do piso, 1428, Ciudad de Buenos Aires, Argentina
a2 Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab 2, 2do piso, 1428, Ciudad de Buenos Aires, Argentina
a3 Instituto Nacional de Parasitología Dr Mario Fatala Chabén, Buenos Aires, Argentina
a4 College of Veterinary Medicine, University of Illinois, Urbana-Champaign, Illinois, USA

Article author query
marcet pl   [PubMed][Google Scholar] 
duffy t   [PubMed][Google Scholar] 
cardinal mv   [PubMed][Google Scholar] 
burgos jm   [PubMed][Google Scholar] 
lauricella ma   [PubMed][Google Scholar] 
levin mj   [PubMed][Google Scholar] 
kitron u   [PubMed][Google Scholar] 
gurtler re   [PubMed][Google Scholar] 
schijman ag   [PubMed][Google Scholar] 


This study applied improved DNA extraction and polymerase chain reaction strategies for screening and identification of Trypanosoma cruzi lineages directly from faeces of triatomines collected in a well-defined rural area in northwestern Argentina. Amplification of the variable regions of the kinetoplastid minicircle genome (kDNA-PCR) was performed in faecal lysates from 33 microscope (MO)-positive and 93 MO-negative Triatoma infestans, 2 MO-positive and 38 MO-negative Triatoma guasayana and 2 MO-positive and 73 MO-negative Triatoma garciabesi. kDNA-PCR detected T. cruzi in 91% MO-positive and 7·5% MO-negative T. infestans, which were confirmed by amplification of the minicircle conserved region. In contrast, kDNA-PCR was negative in all faecal samples from the other triatomine species. A panel of PCR-based genomic markers (intergenic region of spliced-leader DNA, 24Sα and 18S rRNA genes and A10 sequence) was implemented to identify the parasite lineages directly in DNA lysates from faeces and culture isolates from 28 infected specimens. Two were found to be infected with TCI, 24 with TCIIe, 1 with TCIId and 1 revealed a mixed TCI+TCII infection in the faecal sample whose corresponding culture only showed TCII, providing evidence of the advantages of direct typing of biological samples. This study provides an upgrade in the current diagnosis and lineage identification of T. cruzi in field-collected triatomines and shows T. cruziII strains as predominant in the region.

(Received May 11 2005)
(Revised July 11 2005)
(Accepted July 12 2005)
(September 15 2005)

Key Words: Trypanosoma cruzi; Triatoma infestans; Triatoma guasayana; Triatoma garciabesi; Chagas disease; PCR; lineage.

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