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    Geographic location of the indigenous communities in the Sierra Nevada de Santa Marta, Colombia, in an altitudinal gradient on the river basin of the Palomino River with its respective ethnic groups. 1: Manzanal (koguis); 2: Kasakumake (Wiwas); 3: Gumake (Arhuacos), and 4:Umandita (Koguis).

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    Three percent Agarose gel electrophoretic analysis of the signatures obtained by minicircle low-stringency single primer-polymerase chain reaction (LSSP-PCR) of Trypanosoma cruzi samples from patients, vectors, and reservoirs. The patient samples are represented by the letters G (Gumake), U (Umandita), K (Kasakumake), and M (Manzanal), indicating the community to which they belong and followed by its respective code. The samples of vectors are represented by the letter V and reservoirs by the letter R. (A) Profiles that are heterogeneous between T. cruzi samples from patients, vectors, and reservoirs. (B) Profiles shared among samples of T. cruzi. M: 50-bp ladder molecular-weight marker.

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    Dendrogram of samples of Trypanosoma cruzi obtained from patients and vectors. GDV (vector Triatoma dimidiata from Gumake); GPV (vector Rhodnius prolixus from Gumake); UPV (vector R. prolixus from Umandita); KPV (vector R. prolixus from Kasakumake); MPV (vector R. prolixus from Manzanal). (A) Association of patient samples from Gumake, Umandita, Kasakumake, and Manzanal with R. prolixus from Gumake, Umandita, Kasakumake, and Manzanal and T. dimidiata from Gumake. (B) Association of patient samples from Gumake, Kasakumake, Manzanal, and Umandita with R. prolixus from Umandita and Kasakumake. (C) Association of patient samples from Kasakumake, Umandita, and Manzanal with R. prolixus from Manzanal, Umandita, and Gumake and T. dimidiata from Gumake. (D) Association of patient samples from Umandita with R. prolixus from Kasakumake and Manzanal and T. dimidiata from Gumake. (E) Association of patient samples from Umandita with R. prolixus from Kasakumake and Umandita and T. dimidiata from Gumake.

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    Hybridization patterns representative of amplified products of the hypervariable regions of kDNA from patient samples of the four indigenous communities in the Sierra Nevada de Santa Marta (SNSM). (A) V25 probe isolated from Rhodnius prolixus from Gumake. (B) V53 probe isolated from Triatoma dimidiata from Gumake. M: 100-bp molecular-weight marker; G78, G127, G130, G188, and G193: patients from Gumake; K1, K4, K41, K42, and K43: patients from Kasakumake; U9, U10, U12, U17, and U21: patients from Umandita; M1, M14, M23, M24, and M35: patients from Manzanal. The upper part of the figure shows the ethidium bromide-stained 1.5% agarose gel, on which the amplicons were electrophoresed.

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    Model of genetic flux of Trypanosoma cruzi populations that circulate in the four indigenous communities of the Sierra Nevada de Santa Marta (SNSM) in patient, vector, and reservoir samples based on the results obtained.

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Transmission Dynamics of Trypanosoma cruzi Determined by Low-Stringency Single Primer Polymerase Chain Reaction and Southern Blot Analyses in Four Indigenous Communities of the Sierra Nevada de Santa Marta, Colombia

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  • 1 Grupo Biología y Control de Enfermedades Infecciosas, Universidad de Antioquia, Medellín, Colombia; Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile

This study attempted to evaluate the transmission dynamics of Trypanosoma cruzi in four indigenous communities of Sierra Nevada de Santa Marta (SNSM), Colombia. Low-stringency single primer-polymerase chain reaction (LSSP-PCR) of the minicircles and Southern blot analyses were used to characterize samples from patients, vectors, and reservoirs in these communities. The LSSP-PCR profiles revealed a high genetic variability but with similarities among the parasites present in the samples of vectors, patients, and reservoirs of the same and different communities. Cluster and analysis of molecular variance (AMOVA) analyses of data derived from LSSP-PCR and Southern blot suggest a gene flux among populations of T. cruzi circulating in patients, vectors, and reservoirs. The results support the idea that the domestic and wild transmission cycles overlap in the SNSM, with Rhodnius prolixus as the main vector and Triatoma dimidiata playing an important role in the transmission of Chagas disease in this zone, making the vector control strategy by spraying unsuccessful.

INTRODUCTION

Chagas disease is a zoonosis caused by the hemoflagellate parasite Trypanosoma cruzi. In Colombia, this disease affects 900,000 persons and 3 million are at risk of infection.1 The Sierra Nevada de Santa Marta (SNSM) is located on the north coast of Colombia and isolated by mountains rising abruptly from the tropical lowlands, between the delta of the Magdalena River and the northern-most extension of the eastern Cordillera, which reaches a maximum altitude of 5,775 m above sea level. Previous epidemiologic studies have observed low infestation and colonization vector indexes, suggesting a low risk of T. cruzi transmission in the area.2 However, high infection rates of T. cruzi were detected in ethnic groups inhabiting this region. 3,4 In addition, the high number of electrocardiograph abnormalities found (62%) among seropositive compared with seronegative patients suggest that this pathology is mainly caused by infection with T. cruzi.5

Epidemiologic studies reported the presence of domestic and wild vectors in this endemic area. Triatoma dimidiata was the most abundant vector, present in domestic, peridomestic, and wild transmission cycles; Rhodnius prolixus was found in the domestic and peridomestic environments; and Panstrongylus geniculatus only in the wild cycle. Additionally, R. prolixus, T. dimidiata, and P. geniculatus had a high infection index with T. cruzi.6 In this ecosystem, the native palm tree serves as shelter and food for diverse fauna, including insects and wild animals. In addition, analyses with different molecular markers indicated that T. cruzi stocks from R. prolixus and T. dimidiata in SNSM were classified as T. cruzi I. However, random amplification of polymorphic DNA (RAPD) and paraflagellar protein gene sequences were able to differentiate stocks from both environments.7

Because of the multiclonal nature and high genetic heterogeneity of T. cruzi isolates, several molecular techniques have been used to evaluate parasite variability present in naturally infected patients, reservoirs, and triatomines. 8,9 Low-stringency single specific primer-polymerase chain reaction (LSSP-PCR) from the hypervariable region of kDNA minicircles has been widely used to study this variability, because it can analyze direct samples to detect T. cruzi genotypes in tissues. 1012 Similarly, Southern blot analyses from PCR minicircle-amplified DNAs have been used to identify T. cruzi genotypes circulating in endemic areas.8

The objective of the present study was to determine the transmission dynamics of T. cruzi genotypes circulating in four indigenous SNSM communities (Manzanal, Kasakumake, Gumake, and Umandita). For this purpose, LSSP-PCR and Southern blot analyses of minicircles were used to characterize T. cruzi samples from patients, reservoirs, and triatomine insects. It is very important to evaluate associations of different hosts with T. cruzi genotypes from different communities to determine the molecular epidemiology of Chagas disease in this region and to propose control programs.

MATERIAL AND METHODS

Area of study.

The study was conducted in SNSM, located on the basin of the Palomino River at an altitude between 200 and 1,500 m, where the indigenous Manzanal, Kasakumake, Gumake, and Umandita communities are located (Figure 1). Manzanal has 90 inhabitants belonging to the Kogui ethnic group, Kasakumake 150 inhabitants belonging to the Wiwa ethnic group, Gumake 300 inhabitants of the Arhuacos ethnic group, and Umandita 90 inhabitants of the Kogui ethnic group.

Samples.

One hundred twenty-one positive T. cruzi samples from SNSM were obtained directly from insect vector feces, patient blood (10 mL), and domestic and wild reservoir blood (0.2–5.0 mL) (Table 1). Patients were selected for this study based on two serologic tests (enzyme-linked immunosorbent assay [ELISA] and indirect immunofluorescence [IFI]) and molecular diagnosis by PCR. Domestic and wild vectors were captured by active and passive search in the domestic, peridomestic, and sylvatic transmission cycles in the different communities. Domestic reservoirs were considered those that coexist with humans in dwellings and the peridomestic environment comprised dogs, cats, and pigs, whereas all other mammals were considered wild. The University of Antioquia ethics committee approved this study and a written consent form was obtained from all patients.

Extraction of DNA.

The DNA from triatomine feces was purified using DNAzol reagent (Gibco BRL, Gaithersburg, MD), as recommended by the manufacturer, with 25 μL of feces. The DNA from patient and reservoir blood was extracted using the phenol-chloroform method and precipitated with ethanol. 13

All samples were previously characterized as T. cruzi I by PCR amplification of the miniexon gene, isoenzymes analysis, and RAPDs.7

LSSP-PCR of the hypervariable region of minicircles.

Amplification was performed in 0.2-mL microcentrifuge tubes containing 25 μL of reaction mixture. Previously described S35 (5′-AAATAATGTACGGGGAGATGCATGA-3′) and S36 (5′-GGGTTCGATTGGGGTTGGTGT-3′) primers were used for amplification of the variable region of minicircles from different biologic samples. 14 These primers allow amplification of a 330-bp fragment. The reaction mixture contained 1 μL of DNA template, 50 mM of KCl, 10 mM of Tris HCl pH 8.0, 0.1% Triton X-100, 1.5 mM of MgCl2, enzyme buffer 10×, 200 μM of dNTPs, 10 pmol of each primer, and 2.5 U of Taq polymerase (Fermentas, Burlington, Ontario, Canada). The amplifications were performed on a PTC-100 programmable thermal cycler (MJ Research Inc., Waltham, MA) programmed for an initial denaturation step of 94°C for 3 min, followed by 35 cycles at 94°C for 45 s, 63°C for 45 s, 72°C for 45 s, and a final cycle of 72°C for 10 min. Ten microliters of the PCR products were run on 1.5% low-melting-point agarose gel and stained with ethidium bromide. Bands corresponding to 330 bp were cut from the gel and diluted to 1:10 in double-distilled water and warmed to 65°C for 20 min. One microliter of the dilution was used as a template for the LSSP-PCR reaction.9 The LSSP-PCR was performed in 25 μL of the final volume using 50 mM of KCl, 1.5 mM of MgCl2, 120 pmol of the S35 primer, 200 μM of each dNTP, and 4 U of Taq polymerase (Fermentas). The amplification cycles were carried out at an initial temperature of 94°C for 3 min, followed by 35 cycles at 94°C for 45 s, 30°C for 45 s, 72°C for 45 s, and a final cycle at 72°C for 10 min. The amplified products were analyzed by electrophoresis on 3% agarose gel stained with ethidium bromide and visualized under UV light. 15 The LSSP-PCR for each sample was performed in duplicate.

Southern blot analysis.

Southern blot analysis was used with 105 DNA samples of T. cruzi. The PCR products from kDNA were denatured, transferred onto nylon membranes, and cross-linked by UV irradiation. Two selected DNA probes from samples with different LSSP-PCR profiles were selected. The V25 and V53 probes were obtained by amplification of the variable region of T. cruzi minicircles, isolated from R. prolixus (domestic) and T. dimidiata (wild) vectors of Gumake, respectively. Primers for probes generation were CV1 (5′-GATTGGGGTTGGAGTACTAT-3′) and CV2 (5′-TTGAACGGCCCTCCGAAAAC-3′), which produced a 270-bp fragment. 16 These fragments were further digested with restriction endonucleases Sau96I and ScaI to obtain a 250-bp band, and remove all sequences of the constant region.8 Finally, the probes were labeled using the random primer method with [α32P] dCTP.17 The membranes were prehybridized in a solution of 6× SSC and 1 mM of EDTA, pH 7.4, with salmon-sperm DNA at 55°C, and hybridized overnight at 55°C in the same solution with the labeled probe and washed in high-stringency conditions (0.1× SSC, 0.1× SDS, and 68°C). Membranes were exposed for 1–4 h in the Molecular Imager (FX Bio Rad Laboratories, Hercules, CA). This method has been validated by hybridization with probes constructed by PCR amplification of T. cruzi DNA from different genotypes. 8,18 The hybridization profiles were analyzed comparing the intensity of the ethidium bromide-stained bands in each membrane with the radioactive bands obtained with each probe.

Data analysis.

The LSSP-PCR profiles of different samples were used to construct a matrix of 0 and 1, which represent absence or presence of bands, respectively. Genetic diversity among samples, according to their biologic or geographic origin, were compared using the Nei genetic distance and the Neighbor-Joining (NJ) cluster method included in the software PAUP 4.0 (beta version 4.0b10). 19 Two strains of T. cruzi II (CL and JGBH) were used as outgroups.

Genetic differentiation among geographic or biologic population pairwise comparisons and within geographic populations was explored using ΦST and analysis of molecular variance (AMOVA) statistics with 10,000 permutations 20 included in the software GENALEX V 6.0. 21 Bonferroni corrections (Dunn-Sidak method) were used for multiple comparisons. 22 To explore the effect of sample size (Table 1) on pairwise comparisons, different random samples of 20 isolates from Gumake were compared with the original sample.

RESULTS

LSSP-PCR of kDNA.

The LSSP-PCR of T. cruzi kDNA obtained from patients, vectors, and reservoirs of the SNSM displayed a high variability within and among the four communities examined (Figure 2A). Despite this variability, similar profiles were observed among certain patients and also among samples of reservoirs from Gumake (Figure 2B).

Cluster analysis of LSSP-PCR profiles.

To analyze the relationship among the T. cruzi genotypes circulating in the SNSM, one cluster analysis was carried out. A tendency to cluster according to geographic or biologic origin was not observed. Genetic similarities of T. cruzi samples from patients and vectors from the same and different communities were observed (Figure 3). Trypanosoma cruzi samples from R. prolixus of different localities were also clustered with T. cruzi samples of T. dimidiata from Gumake (Figure 3, node A, C, D, and E). In contrast to these similarities, some T. cruzi genotypes of patients from Gumake, Kasakumake, and some domestic reservoirs did not cluster with other patient, vector, and reservoir samples of T. cruzi (data not shown).

AMOVA analysis of LSSP-PCR profiles.

The AMOVA analysis showed genetic differentiation among T. cruzi genotypes by geographic origin between Kasakumake and Umandita communities and between Kasakumake and Gumake when reservoirs were absent (Table 2). The results taking 20 random samples with or without reservoirs from the Gumake community were consistent with the original sample (data not shown).

Comparison of T. cruzi genotypes according to biologic origin showed genetic similarity among R. prolixus with T. dimidiata; patients with T. dimidiata, and patients with R. prolixus(Table 2). Domestic reservoir T. cruzi from Gumake showed genetic differentiation with T. cruzi from R. Prolixus, T. dimidiata and patients. Nevertheless, comparing reservoirs within localities showed genetic similarities with patients from Kasakumake (ΦST: 0.018, P = 0.119) and also with R. prolixus from Manzanal (ΦST: 0.054, P = 0.081) and Gumake (ΦST: 0.025, P = 0.287).

Southern blot analysis.

Forty-five percent of the T. cruzi samples from patients, vectors, and reservoirs hybridized with the T. cruzi V25 probe from R. prolixus, 8% with the V53 probe of T. dimidiata, and 12% with both probes, whereas 35% did not hybridize with either probe, indicating the presence of additional and different T. cruzi genotypes to V25 and V53.

The V25 probe showed hybridization with 66% of samples obtained from patients (Figure 4A), 61% of vector samples from Gumake, Kasakumake, Umandita, and Manzanal hybridized with this probe, and 29% of reservoirs from Gumake. This same probe cross-reacted with isolates of the wild vector T. dimidiata from Gumake, which suggests the presence of similar T. cruzi genotypes in both vectors (Table 3). Meantime, the V53 probe hybridized with 17% of the samples from patients (Figure 4B) from Kasakumake, Gumake, and Umandita, 16% of the vectors from all communities and 33% of the reservoirs (Table 3).

DISCUSSION

Molecular epidemiology studies of T. cruzi are highly important in determining the parasite genotypes circulating in patients, vectors, and reservoirs (domestic and wild) from each endemic zone identifying triatomine insects responsible for transmission of the parasite with the goal of defining adequate control strategies to interrupt the disease.

The LSSP-PCR profiles showed high genetic variability in all the samples analyzed from the SNSM. These results are consistent with other studies, where a great genetic heterogeneity of stocks was detected in T. cruzi I from domestic and sylvatic transmission cycles in Colombia. 12,2328 In addition, Dib and others5 showed that all T. cruzi stocks from SNSM belonged to lineage I. Further studies must be conducted to try to identify the presence of T. cruzi II in this region, due this parasite group has been reported to be associated with wild vectors and mammals in other regions of Colombia. 12,25 Additionally, T. cruzi II was recently detected in the blood of chronic chagasic patients. 29

However, evidence of similar genotypes of T. cruzi among patients and vectors in some SNSM localities was also observed. Cluster analysis of different samples of T. cruzi using LSSP-PCR did not reflect a tendency to associate by geographic or biologic origin of studied samples. Thus, genetic similarities of T. cruzi were found among patients, vectors, and reservoirs from the same and different communities, suggesting the possibility of gene flow among some SNSM localities. This idea is supported by AMOVA analysis where no significant genetic differentiation was detected among T. cruzi samples from Manzanal, Gumake, and Umandita localities and between Kasakumake and Manzanal. Similarly, no genetic differentiation was detected among T. cruzi samples from patients, R. prolixus, T. dimidiata, and among the two vectors. These results were also supported by three observations obtained from Southern blot analysis: 1) V25 and V53 probes hybridizing with samples of T. cruzi originated from patients and vectors of the same and different localities, 2) V25 and V53 probes hybridizing with samples of T. cruzi obtained from R. prolixus and T. dimidiata, and 3) both probes hybridized simultaneously with samples of patients, vectors, and reservoirs, suggesting mixed infections.

The genetic similarities among Manzanal, Gumake, and Umandita communities could be explained by the location of these communities next to the access road to the town of Palomino, which allows interaction among inhabitants from these communities (Figure 5). Although Manzanal is far from Umandita, both communities belong to the same ethnic group and this situation probably explains genetic similarities among their T. cruzi isolates. Through displacement, the natives can be infected by domestic and wild vectors, acquiring similar populations of parasites in all of these communities. An additional and not exclusive alternative is the passive dispersal of domestic or wild triatomine insects among these communities by indigenous migration in SNSM. Even though Kasakumake is not located on the access road, its proximity to Manzanal could explain the T. cruzi genetic similarities found among the two communities and genetic differences when comparing Kasakumake with Umandita and Gumake (Figure 1).

The high hybridization percentage of patients of different communities with the V25 probe (66%) suggests that R. prolixus is responsible for the majority of Chagas disease cases in SNSM. Nevertheless, two observations suggest that T. dimidiata also contributes to transmission of Chagas disease in this area despite its sylvatic habitat: 1) the infection of R. prolixus and T. dimidiata with similar T. cruzi genotypes, evidenced by cross-reactivity of their probes; 2) infection of a few patients with mixed populations of T. cruzi present in R. prolixus and T. dimidiata, evidenced by hybridization patterns with both probes. These observations were also corroborated by cluster and AMOVA analysis of LSSP-PCR results, where no genetic differentiation was observed between samples of T. dimidiata, patients, and R. prolixus (Table 2), supporting previous observations of overlapping domestic and wild transmission cycles in SNSM.6

Moreover, the absence of hybridization in some samples of T. cruzi obtained from reservoirs and some patients with the probes used in our study suggest the existence of other genotypes of the parasite that are circulating in the SNSM. These results are interesting because they may indicate the role played by domestic reservoirs as biologic filters, suggesting that clonal selection could be occurring, probably by selective pressure of the mammal immune system in response to the infection. However, specific genotypes of T. cruzi in reservoirs could also be related to the presence of other insect vectors, such as Panstrongylus geniculatus, which have frequently been seen invading houses in this area, possibly carrying these different genotypes. 30 Further studies must be conducted to address whether sylvatic triatomine species are involved in the transmission of Chagas disease in this zone. In addition, the presence of infected domestic mammals in this region has epidemiologic importance because they are always found in close contact with humans. This relation could be playing an important role in the constant circulation of T. cruzi genotypes in the domestic cycle. The role of domestic mammals as reservoirs of T. cruzi has been demonstrated in rural villages in northwest Argentina. 31 Additionally, our data could indicate the presence of multiclonal stocks in this endemic region. The V25 and V53 probes were selected due its wild and domestic origin, respectively; and based on the similarity of bands shared in the LSSP-PCR profiles with samples of patients and reservoirs. However, it is important to design new probes from reservoirs, patients, and other vectors to identify all the genotypes circulating in this endemic area that were not identified in this study.

Recently, the presence of four haplotypes of T. cruzi I was reported in Colombia. Haplotypes 1 and 3 associated with domestic transmission cycles, while 2 and 4 presented greater likeness with wild transmission cycles. 32,33 Interestingly, they showed in that study that one stock isolated from R. prolixus in SNSM was classified as haplotype 1 and the other one from T. dimidiata as haplotype 2. In our study, we increased the number of samples from these insect vectors in this region, and we showed overlapping among the two transmission cycles. Thus, we propose that haplotypes 1 and 2 are circulating in domestic and wild environments in the SNSM.

Finally, this study supports the idea that in the SNSM the domestic and wild transmission cycles may overlap. These results, together, showed the genetic heterogeneity of T. cruzi in SNSM and the circulation of multiclonal genotypes between the different communities examined. Based on the Southern blot analysis, we propose to R. prolixus as the main vector in the four indigenous communities, but T. dimidiata is also acting in the active transmission of Chagas disease in the zone. Because triatomine vectors in the SNSM (Colombia) are in both transmission cycles, the control strategies must be based not only on spraying, but also on dwelling improvement to make the colonization of wild vectors difficult as well on implementation of educational programs.

Table 1

Samples of Trypanosoma cruzi from patients, vectors, and reservoirs of the Sierra Nevada de Santa Marta (SNSM)

Table 1
Table 2

Analysis of molecular variance (AMOVA) of Trypanosoma cruzi samples by geographic and biologic origin

Table 2
Table 3

Samples of Trypanosoma cruzi obtained from patients, vectors, and reservoirs that hybridize with the V25 and V53 probes*

Table 3
Figure 1.
Figure 1.

Geographic location of the indigenous communities in the Sierra Nevada de Santa Marta, Colombia, in an altitudinal gradient on the river basin of the Palomino River with its respective ethnic groups. 1: Manzanal (koguis); 2: Kasakumake (Wiwas); 3: Gumake (Arhuacos), and 4:Umandita (Koguis).

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 81, 3; 10.4269/ajtmh.2009.81.396

Figure 2.
Figure 2.

Three percent Agarose gel electrophoretic analysis of the signatures obtained by minicircle low-stringency single primer-polymerase chain reaction (LSSP-PCR) of Trypanosoma cruzi samples from patients, vectors, and reservoirs. The patient samples are represented by the letters G (Gumake), U (Umandita), K (Kasakumake), and M (Manzanal), indicating the community to which they belong and followed by its respective code. The samples of vectors are represented by the letter V and reservoirs by the letter R. (A) Profiles that are heterogeneous between T. cruzi samples from patients, vectors, and reservoirs. (B) Profiles shared among samples of T. cruzi. M: 50-bp ladder molecular-weight marker.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 81, 3; 10.4269/ajtmh.2009.81.396

Figure 3.
Figure 3.

Dendrogram of samples of Trypanosoma cruzi obtained from patients and vectors. GDV (vector Triatoma dimidiata from Gumake); GPV (vector Rhodnius prolixus from Gumake); UPV (vector R. prolixus from Umandita); KPV (vector R. prolixus from Kasakumake); MPV (vector R. prolixus from Manzanal). (A) Association of patient samples from Gumake, Umandita, Kasakumake, and Manzanal with R. prolixus from Gumake, Umandita, Kasakumake, and Manzanal and T. dimidiata from Gumake. (B) Association of patient samples from Gumake, Kasakumake, Manzanal, and Umandita with R. prolixus from Umandita and Kasakumake. (C) Association of patient samples from Kasakumake, Umandita, and Manzanal with R. prolixus from Manzanal, Umandita, and Gumake and T. dimidiata from Gumake. (D) Association of patient samples from Umandita with R. prolixus from Kasakumake and Manzanal and T. dimidiata from Gumake. (E) Association of patient samples from Umandita with R. prolixus from Kasakumake and Umandita and T. dimidiata from Gumake.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 81, 3; 10.4269/ajtmh.2009.81.396

Figure 4.
Figure 4.

Hybridization patterns representative of amplified products of the hypervariable regions of kDNA from patient samples of the four indigenous communities in the Sierra Nevada de Santa Marta (SNSM). (A) V25 probe isolated from Rhodnius prolixus from Gumake. (B) V53 probe isolated from Triatoma dimidiata from Gumake. M: 100-bp molecular-weight marker; G78, G127, G130, G188, and G193: patients from Gumake; K1, K4, K41, K42, and K43: patients from Kasakumake; U9, U10, U12, U17, and U21: patients from Umandita; M1, M14, M23, M24, and M35: patients from Manzanal. The upper part of the figure shows the ethidium bromide-stained 1.5% agarose gel, on which the amplicons were electrophoresed.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 81, 3; 10.4269/ajtmh.2009.81.396

Figure 5.
Figure 5.

Model of genetic flux of Trypanosoma cruzi populations that circulate in the four indigenous communities of the Sierra Nevada de Santa Marta (SNSM) in patient, vector, and reservoir samples based on the results obtained.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 81, 3; 10.4269/ajtmh.2009.81.396

*

Address correspondence to Omar Triana-Chávez, Universidad de Antioquia, Calle 62 No 52-59 Laboratorio 620, Medellín, Colombia. E-mail: omar.triana@siu.udea.edu.co

Authors’ addresses: Ingrid B. Rodríguez, Adriana Botero, Ana M. Mejía-Jaramillo, Edna J. Marquez, and Omar Triana-Chávez, Grupo BCEI, Universidad de Antioquia, AA 1226, Calle 62 No. 52-59, Medellín, Colombia. Sylvia Ortiz and Aldo Solari, Programa de Biología celular y molecular, ICBM, Facultad de Medicina, Universidad de Chile, Avenida Independencia 1027, Santiago de Chile, Chile.

Acknowledgments: We thank Juan Carlos Dib and Luz Adriana Agudelo for their help in sample collection.

Financial support: This study was supported in part by the Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología “Francisco Jose de Caldas” (COLCIENCIAS project 1115-04-14387), Proyecto de sostenibilidad, University of Antioquia 2007–2008, and the International Cooperation CONICYT—COLCIENCIAS program 2006.

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