Previous Article | Next Article 
Journal of Clinical Microbiology, February 2002, p. 627-632, Vol. 40, No. 2
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.40.2.627-632.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
Predominance of Trypanosoma cruzi Lineage I in Mexico
Marie-France Bosseno,1* Christian Barnabé,2 Ezequiel Magallón Gastélum,3 Felipe Lozano Kasten,3 Janine Ramsey,4 Bertha Espinoza,5 and Simone Frédérique Brenière1
Institut de Recherche pour le Développement (IRD), UR 008 Pathogénie des Trypanosomatidés,1
UMR CNRS/IRD 9926, Génétique Moléculaire des Parasites et des Vecteurs, 34032 Montpellier Cedex 1, France,4
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70228, CP 04510, Districto Federal,,2
Departamento de Salud Pública del Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, AP 4-119, Guadalajara, Jalisco,3
Center for Infectious Disease Research, National Institute for Public Health, Cuernavaca, 62508 Morelos, Mexico5
Received 10 August 2001/
Returned for modification 29 October 2001/
Accepted 21 November 2001

ABSTRACT
Randomly amplified polymorphic DNA (RAPD) has emerged as an
effective genetic marker for analysis of
Trypanosoma cruzi population
variability. This method has been used to study the genetic
variability of Mexican
T. cruzi stocks and to relate these results
to previous classifications. High clonal diversity was observed
among the Mexican populations: 24 RAPD types were scored among
56 stocks analyzed. Only two stocks (3.6%) belonged to the
T. cruzi II lineage, while all others belonged to
T. cruzi I. The
robustness of these clusters was statistically highly significant.
Mexican
T. cruzi I stocks formed a homogeneous group with reduced
genetic distances among its members. Parasites from this group
were isolated from both domestic and sylvatic cycles over a
broad geographic area in Mexico. The two Mexican stocks classified
as
T. cruzi II (isolated from sylvatic cycles) were of the same
RAPD type, although they were not closely related to the three
reference
T. cruzi II stocks circulating in domestic cycles
in Argentina, Brazil, Bolivia, and Chile. These stocks were
also unrelated to the formerly named Zymodeme III.

INTRODUCTION
Trypanosoma cruzi, the agent of Chagas' disease, which is widely
distributed in Latin America, shows considerable genetic polymorphism
(
14). Extensive studies carried out by using multilocus enzyme
electrophoresis have demonstrated that natural populations of
T. cruzi have a clonal structure (
21), which has led to subdivision
of the taxon into two major lineages,
T. cruzi I and
T. cruzi II (
1,
13,
18,
20). Each lineage is genetically heterogeneous,
and despite failure to identify subdivisions within
T. cruzi I, five subgroups of
T. cruzi II have been proposed as discrete
typing units (DTU) on the basis of randomly amplified polymorphic
DNA (RAPD) analysis (
1,
5). These six DTU have been proposed
as a reference framework for genetic variability and for biological
characterization studies of
T. cruzi stocks.
A few studies have attempted to characterize Mexican T. cruzi stocks by genetic methods. Seventeen stocks were analyzed using HindIII restriction fragment length polymorphisms associated with rRNA gene spacers and kinetoplast DNA maxicircle polymorphisms (9, 12, 22). These studies identified two groups of Mexican stocks, which correlate with geographic origin, although assignment to a T. cruzi lineage was not possible. The same stocks were also analyzed by multilocus enzyme electrophoresis, demonstrating a high degree of heterogeneity that was not related to geographic origin (12). Analysis of minicircle kDNA variability among Mexican stocks showed no correlation between the sequence homologies of the hypervariable region of minicircles and clustering (2), contrasting with results obtained for South American stocks (3, 4).
In the present study, 56 Mexican stocks, isolated from diverse hosts and with diverse geographic origins, were analyzed by RAPD. Relevant phylogenetic analyses were used to assess population variability and structure, and to evaluate the taxonomic position of Mexican stocks and their correspondence with recent T. cruzi classifications.

MATERIALS AND METHODS
Origins of the stocks.
A panel of 56
T. cruzi Mexican stocks was selected from 155
stabilized isolates. Table
1 summarizes the site (by state)
and host origins of the stocks analyzed. Seven previously characterized
reference stocks were also included in the analysis (Table
2).
Parasites were bulk cultured in LIT liquid medium and harvested
by centrifugation, and parasite pellets were stored at -70°C.
Typing by RAPD analysis.
DNAs were extracted from cell pellets as previously reported
(
5), and their concentrations and purities were determined by
spectrophotometry (at 260 and 280 nm) using 10-µl samples.
Samples were aliquoted and stored at -20°C (10 µg/ml).
PCRs were performed in 0.2-ml microcentrifuge tubes containing
60 µl of reaction mixture. The composition of the reaction
mixture and the amplification conditions were identical to those
previously described (
5). Amplifications were performed on a
PTC-100 programmable thermal cycler (MJ Research) programmed
for 45 cycles of 1 min at 94°C, 1 min at 36°C, and 2
min at 72°C, followed by a final elongation step of 7 min
at 72°C. Negative controls using DNA-free water as the template
were added for each PCR procedure. Amplification products were
separated by electrophoresis in a 2% agarose gel (in Tris-acetate-EDTA
[TAE]) and were detected by staining with ethidium bromide.
Data were obtained for the following 10 primers, which gave
the most easily readable and consistent patterns (kit A; Operon
Technology, Alameda, Calif.): OPA-02, OPA-04, OPA-08, OPA-09,
OPA-13, OPA-14, OPA-16, OPA-17, OPA-19, and OPA-20.
Data analysis.
The RAPD Distance Program, version 1.04 (available at ftp://life.anu.edu.au/pub/software/RAPDistance or http://life.anu.edu.au/molecular/software/rapd.html), was used to analyze RAPD bandings, while Jaccard's phenetic distances were used to differentiate between pairs of stocks. Relationships between genotypes were depicted using the UPGMA (unweighted pair group method with arithmetic average) and neighbor-joining methods with the NEIGHBOR program of the PHYLIP package, version 3.5c (Department of Genetics, University of Washington, Seattle). Wagner's parsimony and node robustness were evaluated by bootstrap analysis (7) using Seqboot, Mix, and Consense (PHYLIP package) software. Trees were drawn with the TREEVIEW program (15). A multiple correspondence analysis (MCA) of the same data was performed using the ADE-4 program (19).

RESULTS
RAPD variability.
The 56 Mexican stocks were analyzed with 10 individual primers
by RAPD and compared with the 7 reference stocks (Tables
1 and
2). All amplifications were repeated at least twice, confirming
the reproducibility of the most intense bands. Some low-intensity
bands were not reproducible and therefore were not included
in the comparative analysis. Electrophoresis profiles of the
amplified products for each primer were composed of 1 to 16
DNA fragments ranging in size from 0.2 to 2.5 kb. In total,
66 different DNA fragments were detected and 22 to 30 bands
were generated for each isolate. Twenty-four RAPD types, based
on specific band patterns, were identified among all stocks
(Table
1). Six of the reference stocks had individual RAPD types
not shared with Mexican stocks. Mexican stocks expressed 18
RAPD types; 14 of the Mexican stocks had the R01 RAPD type,
the same as that of the reference stock Sylvio-X10-cl1. Among
the Mexican stocks, individual RAPD patterns were expressed
either in isolated stocks (1 or 2) or in large numbers (e.g.,
R01 was expressed in 14 stocks [Table
1]). Three classes of
bands were observed (Fig.
1) : invariant bands (present in all
RAPD types), singleton bands (present in only one RAPD type),
and parsimony bands (common to multiple RAPD types). Among Mexican
and reference stocks, six invariant bands were identified (9.1%).
These were generated using primers A08 and A20 (1 constant band
each), A02 (1 band of 2 generated with this primer), A04 (2
bands of 12), and A13 (1 band of 16). Nineteen bands were singleton
(29%), and among these, four were observed in Mexican stocks
(R12, R13, R14, and R20 [Table
1]). The majority of the 46 bands
identified in the Mexican stocks (62%) were common to a large
number of RAPD types. Ten of these were invariant bands (22%);
14 were singleton bands (30%), of which 9 were present in RAPD
type R20; and the majority of the 22 common bands were present
in 17 of the 18 RAPD types (Fig.
2).
Clustering analysis.
Jaccard's distances between pairs of RAPD types were calculated,
and the distance matrices were transformed into unrooted trees
by using either the neighbor-joining or the UPGMA method. Similar
branching patterns were obtained by the two methods (Fig.
2).
The majority of stocks clustered into a first group with minor
variability. This group included two reference stocks (SO34-cl4
and Sylvio-X10-cl1) belonging to
T. cruzi I. The second group
was more heterogeneous, with three reference stocks of
T. cruzi II (Esmeraldo-cl3, CBB, and MIZ 03) and two Mexican stocks isolated
from sylvatic mammals. The CAR 30 and CANIII-cl1 reference stocks
were distant from the previous two groups and were subsequently
used as an outgroup for Wagner parsimony analysis (cladistic
method). The Wagner tree confirmed the two principal clusters,
and the bootstrap values obtained at the nodes were highly significant
in both cases (98 and 92% for
T. cruzi I and
T. cruzi II, respectively
[see Fig.
2]). In the absence of a more pertinent outgroup (CAR
30 and CANIII-cl1 belong to the
T. cruzi taxon), it was impossible
to assign CAR 30 and CANIII-cl1 to either
T. cruzi I or
T. cruzi II by cluster analysis. Hence, MCA was used with the 66 variables
to test CAR 30 and CANIII-cl1 assignment to
T. cruzi I or II
(Fig.
3). The two first axes explained 47.6% of the complete
variability, and statistical analysis confirmed with a significant
absence of overlap that the stocks attributed to
T. cruzi I
and
T. cruzi II (see above) are distinct groups (
P = 0.01 for
the MCA performed without CAR 30 and CANIII-cl1). The MCA analysis
including CAR 30 and CANIII-cl1 stocks demonstrated that these
stocks belonged to
T. cruzi II (
P = 0.1) and not to
T. cruzi I (
P = 0.1).
Ver 03 and Ver 06 stocks had banding patterns distinct from
those of other Mexican stocks and clustered specifically with
T. cruzi II by all analyses. Nevertheless, they were also significantly
distinct from other members of
T. cruzi II (average Jaccard's
genetic distance from other members of
T. cruzi II, 0.30 ±
0.02) and from the former Zymodeme III group (CANIII-cl1 [
13]),
with a Jaccard distance of 0.55.

DISCUSSION
Mexican stocks belong to T. cruzi I.
T.
cruzi is composed of natural clones which have broad biological
heterogeneity. Despite this heterogeneity, previous population
genetics studies have attempted to classify
T. cruzi stocks
into discrete phylogenetic subgroups. Two clear DTU corresponding
to the formerly designated
T. cruzi I and
T. cruzi II have been
identified, and the latter DTU has been additionally divided
into five subdivisions by use of both isoenzyme and RAPD markers
(
1,
5). This classification should be considered a tentative
basis for future genetic diversity and biological property studies
of
T. cruzi. Although the biological diversity of these clusters
remains unclear, several studies suggest that clonal diversity
does have an impact on the biological behavior of
T. cruzi stocks
(
10,
16,
17). In order to further study this correlation, information
regarding the genetic diversity of stocks circulating within
a country is essential.
In order to study the genetic diversity of T. cruzi populations in Mexico, a large sample of stocks isolated from eight states, four principal vector species, humans, and sylvatic mammals was selected. The results clearly demonstrate that most Mexican T. cruzi stocks (except for 2.4%) belong to the T. cruzi I lineage. Different statistical analyses cluster these isolates with two reference stocks belonging to T. cruzi I. Given the prevalence of seropositive individuals and of disease cases in the country, T. cruzi I stocks can be considered the primary agents of Chagas' disease in Mexico (8). The two Mexican stocks Ver 03 and Ver 06 were not closely related to the T. cruzi II reference stocks CBB, MIZ 03, and Esmeraldo-cl3, although they unequivocally clustered with them. This result contrasts with the situation in several South American countries, where parasites belonging to T. cruzi II play a major role in human infection. Furthermore, comparison of these stocks with the formerly described Zymodeme III, which is associated with sylvatic cycles, demonstrates that they are unrelated.
Mexican stocks belonging to T. cruzi I are closely related to each other. The lack of variability detected among the Mexican T. cruzi I stocks was notable compared to the total variability of the stocks studied. Of the 66 RAPD-scored bands, 41 were present in T. cruzi I Mexican stocks and 40% of them were invariant, while banding homology between pairs of stocks ranged from 86 to 99%. Furthermore, the absence of significant bootstrap values at the nodes precludes subdivision of this group by cladistic analysis (all <55%; average value, 20.4% ± 16%). The stock cluster into one group by using the MCA method (data not shown), indicating a clear absence of secondary structure. The average genetic distance (Jaccard's distances) calculated between pairs of Mexican T. cruzi I stocks (0.08 ± 0.04) was much lower than that with other T. cruzi I samples. A broad sample, representative of the geographic distribution of T. cruzi stocks tested, had an average Jaccard genetic distance of 0.36 ± 0.13 (2); with a reduced sample of stocks from sylvatic cycles isolated in French Guiana, the distance was similar, 0.36 ± 0.12 (11). Consequently, the reduced polymorphism among Mexican stocks is remarkable, given their broad geographic distribution, varied hosts, and isolation from domestic and sylvatic hosts. They belong to a single homogeneous group.
Previous studies favored the possibility of broad biological variability among Mexican stocks. Espinoza et al. (6) described low- and high-virulence stocks (more than 80% of infected mice killed) in a murine model associated with different genotypes characterized by rRNA gene spacer polymorphism. All of these stocks can now be classified as T. cruzi I. Therefore, genetic homogeneity by RAPD does not correlate with virulence heterogeneity. Further studies of pathogenic mechanisms will be necessary in order to better understand the biological implications of the microvariability among Mexican stocks.

ACKNOWLEDGMENTS
This work was supported by the TDR of the World Health Organization
(grant ID 970943), the Institut de Recherche pour le Développement
(DGAPA IN 224798 UNAM), and Conacyt (27951 M).

FOOTNOTES
* Corresponding author. Mailing address: Institut de Recherche pour le Développement (IRD), UR 008 Pathogénie des Trypanosomatidés, 911 Av. Agropolis, BP 5045, 34032 Montpellier Cedex 1, France. Phone: (33) 4 67 41 62 98. Fax: (33) 4 67 41 63 30. E-mail:
breniere{at}mpl.ird.fr.


REFERENCES
1
- Barnabé, C., S. Brisse, and M. Tibayrenc. 2000. Population structure and genetic typing of Trypanosoma cruzi, the agent of Chagas disease: a multilocus enzyme electrophoresis approach. Parasitology 120:513-526.
2
- Bosseno, M. F., B. Espinoza, B. Sanchez, and S. F. Brenière. 2000. Mexican Trypanosoma cruzi stocks: analysis of minicircle kDNA homologies by cross-hybridization. Mem. Inst. Oswaldo Cruz (Rio de Janeiro) 95:473-476.[Medline]
3
- Bosseno, M. F., N. Yacsik, F. Vargas, and S. F. Brenière. 2000. Selection of Trypanosoma cruzi clonal genotypes (clones 20 and 39) isolated from Bolivian triatomines following subculture in liquid medium. Mem. Inst. Oswaldo Cruz (Rio de Janeiro) 95:601-607.[Medline]
4
- Brenière, S. F., M. F. Bosseno, J. Telleria, B. Bastrenta, N. Yacsik, F. Noireau, J. L. Alcazar, C. Barnabé, P. Wincker, and M. Tibayrenc. 1998. Different behavior of two Trypanaosoma cruzi major clones: transmission and circulation in young Bolivian patients. Exp. Parasitol. 89:285-295.[CrossRef][Medline]
5
- Brisse, S., C. Barnabé, and M. Tibayrenc. 2000. Identification of six Trypanosoma cruzi phylogenetic lineages by random amplified polymorphic DNA and multilocus enzyme electrophoresis. Int. J. Parasitol. 30:35-44.[CrossRef][Medline]
6
- Espinoza, B., J. M. Vera-Cruz, H. Gonzalez, E. Ortega, and R. Hernandez. 1998. Genotype and virulence correlation within Mexican stocks of Trypanosoma cruzi isolated from patients. Acta Trop. 15:63-72.[CrossRef]
7
- Felsenstein, J. 1985. Confidence limits on phylogenies: an approach using bootstrap. Evolution 39:783-791.[CrossRef]
8
- Guzman Bracho, C., L. García García, J. Floriani Verdugo, S. Guerrero Martínez, M. Torres Cosme, C. Ramírez Melgar, and O. Velasco Castrejón. 1998. Riesgo de transmisión de Trypanosoma cruzi por transfusión de sangre en México. Rev. Panam. Salud Publica 2:94-99.
9
- Hernandez, R., F. Diaz-de Leon, and M. Castaneda. 1988. Molecular cloning and partial characterization of ribosomal RNA genes from Trypanosoma cruzi. Mol. Biochem. Parasitol. 27:275-280.[CrossRef][Medline]
10
- Laurent, J. P., C. Barnabé, V. Ouesney, S. Noel, and M. Tibayrenc. 1997. Impact of clonal evolution on the biological diversity of Trypanosoma cruzi. Parasitology 114:213-218.
11
- Lewicka, K., S. F. Brenière, C. Barnabé, J. P. Dedet, and M. Tibayrenc. 1995. An isoenzyme survey of Trypanosoma cruzi genetic variability in sylvatic cycles from French Guiana. Exp. Parasitol. 81:20-28.[CrossRef][Medline]
12
- López-Olmos, V., N. Pérez-Naser, D. Piñero, E. Ortega, R. Hernández, and B. Espinoza. 1998. Biological characterization and genetic diversity of Mexican isolates of Trypanosoma cruzi. Acta Trop. 69:239-254.[CrossRef][Medline]
13
- Luquetti, A., A. Prata, A. Moncayo, A. Romanha, A. Jansen, B. Zingales, C. Morel, C. Ponce, E. Chiari, E. Cupilillo, E. Ponce, F. Guhl, H. Momen, J. R. Coura, R. Steindel, M. Miles, M. Tibayrenc, O. Fernandes, R. Oliveira, R. Zeledón, S. Andrade, T. Barrett, V. Macedo, and Z. Brener. 1999. Recommendations from satellite meeting. Mem. Inst. Oswaldo Cruz 94(Suppl. 1): 1-6.
14
- Miles, M. A., S. M. Lanham, A. A. De Souza, and M. Póvoa. 1980. Further enzymic characters of Trypanosoma cruzi and their evaluation for strain identification. Trans. R. Soc. Trop. Med. Hyg. 74:221-237.[CrossRef][Medline]
15
- Page, R. D. M. 1996. TREEVIEW: an application to display phylogenetic trees on personal computers. Comput. Appl. Biosci. 12:357-358.[Free Full Text]
16
- Revollo, S., B. Oury, J. P. Laurent, C. Barnabé, V. Ouesney, V. Carriere, S. Noel, and M. Tibayrenc. 1998. Trypanosoma cruzi: impact of clonal evolution of the parasite on its biological and medical properties. Exp. Parasitol. 89:30-39.[CrossRef][Medline]
17
- Solari, A., S. Muñoz, J. Venegas, A. Wallace, X. Aguilera, W. Apt, S. F. Brenière, and M. Tibayrenc. 1992. Characterization of Chilean, Bolivian and Argentinian Trypanosoma cruzi populations by restriction endonuclease and isoenzyme analysis. Exp. Parasitol. 75:187-195.[CrossRef][Medline]
18
- Souto, R. P., O. Fernandes, C. Macedo, D. A. Campbell, and B. Zingales. 1996. DNA markers define two major phylogenetic lineages of Trypanosoma cruzi. Mol. Biochem. Parasitol. 83:141-152.[CrossRef][Medline]
19
- Thioulouse, J., D. Chessel, S. Dolédec, and J. M. Olivier. 1997. ADE-4: a multivariate analysis and graphical display software. Statistics Comput. 7:75-83.
20
- Tibayrenc, M. 1995. Population genetics of parasitic protozoa and other microorganisms. Adv. Parasitol. 36:47-115.[Medline]
21
- Tibayrenc, M., P. Ward, A. Moya, and F. J. Ayala. 1986. Natural populations of Trypanosoma cruzi, the agent of Chagas disease, have a complex multiclonal structure. Proc. Natl. Acad. Sci. USA 83:115-119.[Abstract/Free Full Text]
22
- Zavala-Castro, J. E., O. Velasco-Castrejon, and R. Hernández. 1992. Molecular characterization of Mexican stocks of Trypanosoma cruzi using total DNA. Am. J. Trop. Med. Hyg. 47:201-209.
Journal of Clinical Microbiology, February 2002, p. 627-632, Vol. 40, No. 2
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.40.2.627-632.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Bosseno, M.-F., Barnabe, C., Sierra, M. J. R., Kengne, P., Guerrero, S., Lozano, F., Ezequiel, K., Gastelum, M., Breniere, S. F.
(2009). Wild Ecotopes and Food Habits of Triatoma longipennis Infected by Trypanosoma cruzi Lineages I and II in Mexico. Am J Trop Med Hyg
80: 988-991
[Abstract]
[Full Text]
-
Pennington, P. M., Paiz, C., Grajeda, L. M., Cordon-Rosales, C.
(2009). Concurrent Detection of Trypanosoma cruzi Lineages I and II in Domestic Triatoma dimidiata from Guatemala. Am J Trop Med Hyg
80: 239-241
[Abstract]
[Full Text]
-
Martins, L. P. A., Marcili, A., Castanho, R. E. P., Therezo, A. L. S., de Oliveira, J. C. P., Suzuki, R. B., Teixeira, M. M. G., da Rosa, J. A., Speranca, M. A.
(2008). Rural Triatoma rubrovaria from Southern Brazil Harbors Trypanosoma cruzi of Lineage IIc. Am J Trop Med Hyg
79: 427-434
[Abstract]
[Full Text]
-
Reyes, J. L., Terrazas, L. I., Espinoza, B., Cruz-Robles, D., Soto, V., Rivera-Montoya, I., Gomez-Garcia, L., Snider, H., Satoskar, A. R., Rodriguez-Sosa, M.
(2006). Macrophage Migration Inhibitory Factor Contributes to Host Defense against Acute Trypanosoma cruzi Infection.. Infect. Immun.
74: 3170-3179
[Abstract]
[Full Text]
-
BOSSENO, M.-F., GARCIA, L. S., BAUNAURE, F., GASTELUM, E. M., GUTIERREZ, M. S., KASTEN, F. L., DUMONTEIL, E., BRENIERE, S. F.
(2006). IDENTIFICATION IN TRIATOMINE VECTORS OF FEEDING SOURCES AND TRYPANOSOMA CRUZI VARIANTS BY HETERODUPLEX ASSAY AND A MULTIPLEX MINIEXON POLYMERASE CHAIN REACTION. Am J Trop Med Hyg
74: 303-305
[Abstract]
[Full Text]
-
MELNIKOV, V. G., VELASCO, F. F., GOMEZ, F. E., RODRIGUEZ, F. G., DOBROVINSKAYA, O. R.
(2005). PATHOLOGIC CHANGES IN LUNGS CAUSED BY MEXICAN ISOLATES OF TRYPANOSOMA CRUZI IN THE ACUTE PHASE OF INFECTION IN MICE. Am J Trop Med Hyg
73: 301-306
[Abstract]
[Full Text]