Genetic variability of Trypanosoma cruzi TcI isolates from rural and urban areas of Venezuela
María G Rivera1, Leidi Herrera2, Antonio Morocoima3, Cruz M Aguilar4, Teresa Gárate5, Mariela López1, María Lares1, Mercedes Viettri1, Elizabeth Ferrer6
1 Instituto de Investigaciones Biomédicas "Dr. Francisco J. Triana Alonso" (BIOMED) Universidad de Carabobo Sede Aragua, Maracay, Venezuela
2 Instituto de Zoología y Ecología Tropical (IZET), Facultad de Ciencias, Universidad Central de Venezuela (UCV), Caracas, Venezuela
3 Centro de Medicina Tropical de Oriente, Universidad de Oriente (UDO) Núcleo Anzoátegui, Barcelona, Venezuela
4 Centro de Investigaciones en Enfermedades Tropicales (CIET-UC), Facultad de Ciencias de la Salud, San Carlos, Cojedes. Universidad de Carabobo, Venezuela
5 Instituto de Salud Carlos III, Centro Nacional de Microbiología, Majadahonda, Madrid, Spain
6 Instituto de Investigaciones Biomédicas "Dr. Francisco J. Triana Alonso" (BIOMED); Departamento de Parasitología, Facultad de Ciencias de la Salud, Universidad de Carabobo Sede Aragua, Maracay, Venezuela
BIOMED, Final de Calle Cecilio Acosta, Urb. La Rinconada, Las Delicias, Maracay, edo. Aragua
Source of Support: None, Conflict of Interest: None
Background & objectives: Several studies have demonstrated genetic heterogeneity in populations of Trypanosoma cruzi that allowed the identification of six different discrete typing units (DTU) classified as TcI, TcII, TcIII, TcIV, TcV and TcVI. Furthermore, some characterization studies have described genetic variability within TcI isolates from endemic regions. The objective of the present study was to analyze Venezuelan T. cruzi isolates, obtained from triatomine-vectors, mammal-hosts including infected humans, detected in both rural and urban areas from diverse geographic origins.
Methods: Molecular characterization of 44 Venezuelan T. cruzi isolates, obtained from triatomine-vectors, mammalian hosts and human patients from both rural and urban areas of different geographic origins, were carried out. Samples were analyzed by PCR amplification of the intergenic region of the mini-exon gene, 24Sα rDNA and 18S rDNA, followed by sequencing of the amplification products.
Results: The TcI amplification pattern was found in 42 out of 44 (95.5%) isolates; a TcIII strain and one possible TcIV were also found. The sequence analysis of the TcI Venezuelan isolates showed genetic variability among them. Urban isolates formed a homogeneous group, with differences in their sequences, when compared to rural isolates.
Interpretation & conclusion: The results showed genetic heterogeneity in Venezuelan TcI strains, probably in response to different environmental conditions.