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Natural infection and distribution of triatomines (Hemiptera: Reduviidae) in the state of Querétaro, Mexico
Abstract
Chagas disease is present in Mexico but data on the presence of its vectors are not known for all the states. We conducted an epidemiological study to ascertain the presence of bedbugs in 23 communities of seven municipalities in the state of Querétaro, Mexico. Sampling was performed within and outside dwellings, using the technique of one person searching per hour per house. Four triatomine species were found: Triatoma mexicana (94%), Tri. dimidiata (3%), Tri. gerstaeckeri (2%) and Tri. pallidipennis (1%). Triatoma mexicana was found in six of the seven municipalities but has previously been found only in the state of Hidalgo, where it is considered the most important vector species of Trypanosoma cruzi. This is the first time that the presence of Tri. gerstaeckeri or Tri. dimidiata has been reported in the state of Querétaro. Tolimán municipality had the highest entomological indices: infestation index 73%; infection index 34.5%; crowding index 9.2%; density index 6.7%; and colonization index 20.6%. Although the prevalence and colonization indices were low, the infestation and infection indices indicate that different Triatoma species are becoming established in Querétaro. This work represents the first entomological study in this Mexican state and suggests that some triatomine vectors are extraordinarily mobile.
... (DUMONTEIL et al., 2002) Climate Land use Some individuals were found in a dry climate on an extensive pastureland. (Villagrán et al., 2008) Outdoor shelters Houses located near public light poles are at higher risk for being infested by T.dimidiata. Outdoor shelters For peridomestic infestation, the presence of dogs, cats, goats and cows was important. ...
... Has been found in and outside dwellings. (Villagrán et al., 2008) Indoor shelters Outdoor shelters Has been found in the typical places where one should expect to find the bugs. (Villagrán et al., 2008) Life cycle Egg to adult, 8.5 months on average, high temperatures and relative humidity shortens the development of the species (Martínez-Ibarra et al., 2008) Climate Compared the temperature and humidity conditions of T. mexicana and T. barberi, T. Mexicana had more specific requirements of temperature and relative humidity than T. barberi. ...
... (Villagrán et al., 2008) Indoor shelters Outdoor shelters Has been found in the typical places where one should expect to find the bugs. (Villagrán et al., 2008) Life cycle Egg to adult, 8.5 months on average, high temperatures and relative humidity shortens the development of the species (Martínez-Ibarra et al., 2008) Climate Compared the temperature and humidity conditions of T. mexicana and T. barberi, T. Mexicana had more specific requirements of temperature and relative humidity than T. barberi. There were places where both could be found. ...
Chagas disease is a parasitic infection endemic to America, caused by the protozoan Trypanosoma cruzi and mainly transmitted to humans by contact with insect species of the Triatominae subfamily (Hemiptera). The disease is known to affect disproportionally rural impoverished human communities where it is known to cause premature death and is considered a social and economic burden. The Mexican government has made important progress into the detection, surveillance, treatment, and prevention of the disease in the last decades, however, Chagas disease has also been reported in areas where it had not been previously reported, and there are still barriers for access to treatment. In the state of San Luis Potosi, the disease is more studied in the east, nevertheless, it has been estimated that the reported cases of the entire state have been underestimated. New approaches to detect Chagas risk areas could help prioritize locations for Chagas disease education and prevention programs, detect cases of the disease in a timely manner, and provide access to the necessary treatments. The objective of this study was to identify risk areas for the transmission of Chagas disease in San Luis Potosí using species distribution modelling to estimate vectors and reservoirs’ distributions. To do this, firstly, important vectors and one reservoir species of T. cruzi were identified by reviewing their reported infection rates in literature and the number of times reported in Mexico. Next, species distribution models were calculated for the chosen vector and reservoir species present in the state. The models were done using the Maxent algorithm. Lastly, the resulting distribution models were combined into a risk map by thresholding the model outputs to produce binary predictions and then performing an overlap spatial analysis. Vector species were found to have suitable areas in 36.08% of the state’s territory while areas suitable for both vectors and reservoir were 7.4% of the state’s total area. While this figure may look small at first glance, the analysis suggests that 30% of the rural population and 52% of the urban population of the state are living in an area suitable for vectors and reservoir and therefore at risk. Species distribution modelling can be a powerful tool for identifying human populations at risk of contracting Chagas disease. In the future, including different species of reservoirs into the analysis could help to discover new risk areas in the state.
... The geographic distribution of T. gerstaeckeri covers ten states of the country, mainly in the northern zone. However, there is little data on their behavior; in Querétaro, a natural infection rate of 22% was described, which is similar to that obtained in this work, and, in the same way, all the collected specimens were intradomiciliary (Villagrán et al. 2008, Salazar-Schettino et al. 2010. Despite being the third-highest species in abundance, its high rate of infection and its intradomiciliary microhabitat make T. gerstaeckeri a risk vector for the population of the state of Hidalgo. ...
... In the neighboring state of Querétaro, an infection rate of 20.7% has been reported, which is ten times greater than the one reported in the present work. However, in the state of Guanajuato, where T. mexicana has also been described, an infection rate of only 2.9% was reported (López-Cárdenas et al. 2005, Villagrán et al. 2008. It should be noted that the two studies carried out in the state of Hidalgo presented a low colonization index; specifically, the colonization index found in the study carried out in the municipality of Metztitlán was zero. ...
... The adults that were collected, which were mostly males, were limited only to the peridomicile, suggesting that they only moved in search of a feeding source. The populations of T. mexicana in Guanajuato and Querétaro have been reported mainly in the domicile and peridomicile, suggesting that they have adapted to human dwellings (López-Cárdenas et al. 2005, Villagrán et al. 2008, Becerril-Flores et al. 2007, 2010. ...
Chagas disease represents a significant public health problem in Mexico. In the state of Hidalgo, studies on the presence of triatomines are scarce and restricted to a few locations. To determine the risk of transmission in the state of Hidalgo and stratify the vector potential, the distribution of Triatominae was surveyed from 2015 to 2016 in collaboration with primary health care services and local communities. A total of 570 specimens was collected in 278 houses in 25 municipalities. The species of Triatominae detected were T. dimidiata with 391 samples, T. mexicana with 159 samples, T. gerstaeckeri with 17 samples, and T. barberi with three samples. The samples were collected in domestic and peridomestic areas. The general index of natural infection was 9.8%. Indices of colonization and crowding were determined for species and municipality and results were variable.
... Since then, its geographic distribution has been reported in central Mexico including the States of Guanajuato, Queretaro, and San Luis Potosi ). Despite its importance as a vector of Chagas disease, there are few studies on its geographic distribution (Vidal-Acosta et al. 2000;López-Cárdenas et al. 2005;Villagran et al. 2008), entomological indices (Becerril-Flores et al. 2010Antonio-Campos et al. 2019), biological behavior (Salazar-Schettino et al. 2007;Martínez-Ibarra et al. 2008), and morphological description Rivas et al. 2021). There are only two studies on T. mexicana population genetics and phylogeny (Espinoza et al. 2013;Aguilera-Uribe et al. 2020), and genetic processes related to intraspecific variation, population structure, genetic drift, migration, gene flow, introgression, and pesticide resistance in this species remain largely unknown. ...
... Rather, there is strong evidence that there are probably multiple species within T. mexicana populations. We propose that the variations reported in T. mexicana regarding the geographic distribution (Vidal-Acosta et al. 2000;López-Cárdenas et al. 2005;Villagran et al. 2008 (Espinoza et al. 2013) differences are due to the presence of different species, some of them cryptic and some clearly differentiated . Determining the presence of clinal variations, cryptic species, and new species in triatomines vectors of T. cruzi is an important contribution to medical entomology for designing sound strategies for preventing vector transmission of Chagas disease. ...
Triatoma mexicana is an important vector of Trypanosoma cruzi—the etiological agent of Chagas disease. This triatomine species occurs in central Mexico, but little is known about its genetic variability. Using Cyt-b gene as a genetic marker, in this study, we determined the population genetic structure of T. mexicana collected from the States of Hidalgo, Guanajuato, and Queretaro where populations are largely peridomiciliary. A Bayesian approach was performed for the design of phylogenies, median-joining networks, and clustering among populations of T. mexicana. Our results show that the Hidalgo population was the most distinct, with the highest genetic and haplotypic variation (Hd = 0.963, π = 0.06129, and ɵ = 0.05469). Moderate gene flow (Nm) was determined among populations of Hidalgo and Queretaro. Populations from the three states showed differentiation (FST) values ranging from 0.22 to 0.3, suggesting an important genetic differentiation. The phylogenetic analysis showed the presence of five well-defined groups, as well as the haplotype network, where 24 haplotypes were observed forming five haplogroups with high mutational steps among them: 68 (Hgo-W2), 26 (Qto), 59 (Hgo-M), 44 (Hgo-W1), and 46 (Gto). Genetic isolation was apparently inferred in the Guanajuato population; however, the Mantel test did not show correlation between genetic (FST) and geographic (km) distances (p = 0.05). The STRUCTURE analyses showed seven genetic clusters and it was observed that a single cluster predominates in each sampled location. However, genetic admixture was detected in four localities. Our results show evidence that there are multiple species within the collected sampling area.
... The presence of T. pallidipennis in Hidalgo state extended the distribution of the species already considered to be the most widely distributed in Mexico. The presence of the species had been registered in neighboring states such as Querétaro (Villagrán et al. 2008), Veracruz (Vidal-Acosta et al. 2000, Puebla, and Estado de México (Salazar-Schettino et al. 2010), showing the diversity of microhabitats that they can colonize. ...
Triatoma pallidipennis is an exclusive and widely distributed species in Mexico and one of the three main vectors that transmit Chagas disease in the country. The state of Hidalgo is an endemic area for Chagas disease where the presence of several species of triatomines has been reported. The objective of our work was to describe the morphology, colonization process, and reproductive behavior of T. pallidipennis in Guadalupe, Tecozautla, two years after the first collection of a specimen in this region. A total of 28 specimens was collected at both domicile and peridomicile, showing a 17.8% infection rate. The main collection site was a woodshed, and despite the collection of adults in the dwelling, we did not find eggs, exuviae, or nymphs. One female monitored from collection day until death laid 566 eggs, with a hatching rate of 95%, showing an increase of oviposition when cohabited with a male. The results showed the capacity that T. pallidipennis has to infest areas (mainly human dwellings) when it settles down, which would imply a risk for the population that lives in the locality.
... The population of Queretaro has been described as domestic and peri-domestic, being in a third of the state territory, mainly associated with regions dedicated to agriculture, presenting an infection rate of 28.7%, higher than reported in the neighboring state of Guanajuato (Villagrán et al. 2008). In the state of Hidalgo, the reports show a contrast between their two populations. ...
Triatoma mexicana is an endemic species of Mexico and is distributed in the states of Hidalgo, Queretaro, Guanajuato, and San Luis Potosi, being naturally infected with Trypanosoma cruzi, which increases its importance in the region. The species description was made in 1848, but there are only a few studies on its morphology, biology, and behavior. The present manuscript shows the presence of morphological and chromatic variations among populations of T. mexicana from the states of Hidalgo (Valle del Mezquital and Meztitlan), Guanajuato and Queretaro. The study employed 136 specimens collected in four locations. Scanning electron microscopy was used to study the morphological characteristics of the head, pronotum, and scutellum; also, we measured the width of the abdomen and the total length in the specimens of each population. The morphometric analysis considered 19 variables in the previous structures. Significant differences were found in the dimensions of the head and pronotum, but not in the scutellum; there is clear discrimination among the four proposed populations. The chromatic patterns observed in the connexivum go from yellow to brown and show some significant differences related to geographical origin. The set of evaluated characters showed a higher degree of difference in the population of Guanajuato, clearly separating from the rest of the populations, indicating the possibility of a divergence process. The characteristics observed in the remaining populations could be adaptive responses to their habitat.
... Although there are records for vectors of the studied parasites, (at least for T. cruzi) in some parts of the state of Querétaro (Villagrán et al., 2008), no potential vectors have been reported for the study region of the metropolitan zone of Queretaro City. In order to support the positive results of the presence of T. cruzi and L. mexicana and assess the epidemiological risk factors to humans in this metropolitan area, more evidence concerning the life cycles of these parasites are needed. ...
Trypanosoma cruzi and Leishmania mexicana are parasites of humans and other mammals, causing American Trypanosomiasis and Cutaneous Leishmaniasis, respectively. Domestic dogs are considered key hosts for these parasites in the domicile and peridomicile cycles of transmission, due to their abundance and contact with human population. In Mexico, there are few studies that involve the study of infection with these parasites in dogs, and have only been carried out mainly in the endemic areas for these diseases. In the state of Querétaro (Mexico), infections with both parasites have been reported for dogs only from rural areas, with no records for the metropolitan zone.
We analyzed the seropositivity to T. cruzi and L. mexicana in dogs from localities within of the metropolitan zone of Querétaro City in order to determine if these animals are exposed to these parasites and thus, could be an important part of the transmission cycle of these trypanosomatids in a densely populated urban region within the state of Querétaro, Mexico.
Serum samples were collected from 303 dogs housed in the Animal Control centers of the municipalities of Querétaro and El Marques, analyzed by indirect ELISA and Western Blot using as an antigen the Iron Superoxide Dismutase (FeSODe) of the parasites.
From the total serum samples, we detected 10.2% of seropositivity for T. cruzi and 2.9% for L. mexicana. Our results represent the first evidence of infection with T. cruzi in domestic dogs from the Metropolitan Zone of Querétaro, and the first record for L. mexicana in Central Mexico. Ongoing investigations seek to confirm the circulation of these parasites in the area to evaluate the risk associated to the human population.
... Although this method implies a detection error, it has been safely validated so the error is minor [56]. This validation is based on the fact that the high motility of the parasite makes it very conspicuous during microscopic surveillance [57]. ...
Background:
Theory predicts that parasites can affect and thus drive their hosts' niche. Testing this prediction is key, especially for vector-borne diseases including Chagas disease. Here, we examined the niche use of seven triatomine species that occur in Mexico, based on whether they are infected or not with Trypanosoma cruzi, the vectors and causative parasites of Chagas disease, respectively. Presence data for seven species of triatomines (Triatoma barberi, T. dimidiata, T. longipennis, T. mazzottii, T. pallidipennis, T. phyllosoma and T. picturata) were used and divided into populations infected and not infected by T. cruzi. Species distribution models were generated with Maxent 3.3.3k. Using distribution models, niche analysis tests of amplitude and distance to centroids were carried out for infected vs non-infected populations within species.
Results:
Infected populations of bugs of six out of the seven triatomine species showed a reduced ecological space compared to non-infected populations. In all but one case (T. pallidipennis), the niche used by infected populations was close to the niche centroid of its insect host.
Conclusions:
Trypanosoma cruzi may have selected for a restricted niche amplitude in triatomines, although we are unaware of the underlying reasons. Possibly the fact that T. cruzi infection bears a fitness cost for triatomines is what narrows the niche breadth of the insects. Our results imply that Chagas control programmes should consider whether bugs are infected in models of triatomine distribution.
... As for the protozoa Trypanosoma cruzi, the causative agent of Chagas disease, there exist a plethora of methods to diagnose infection in humans (Luquetti and Schmunis 2010) and some have been adapted to the detection of the parasite in the vectors, i.e., in the kissing bugs (Hemiptera: Reduviidae: Triatominae). In epidemiological studies, the computation of prevalence of infection in Chagas vectors commonly uses two kinds of methods to detect T. cruzi: (1) the direct observation of the parasites by optical microscopy in the bug feces (obtained after pressuring the abdomen of the living insect) (Martinez-Ibarra et al. 2011, Medrano-Mercado et al. 2008, Villagran et al. 2008) and (2) the PCR detection of parasite DNA in the midgut and rectum tissues after dissection of the insect (Dorn et al. 2001, Ibanez-Cervantes et al. 2013. The observation by microscope is fast and can be easily carried out in field conditions. ...
The study aimed to quantify the bias from parasite detection methods in the estimation of the prevalence of infection of Triatoma infestans by Trypanosoma cruzi, the agent of Chagas disease. Three common protocols that detect T. cruzi in a sample of 640 wild-caught T. infestans were compared: (1) the microscopic observation of insect fecal droplets, (2) a PCR protocol targeting mini-exon genes of T. cruzi (MeM-PCR), and (3) a PCR protocol targeting a satellite repeated unit of the parasite. Agreement among protocols was computed using Krippendorff Kα. The sensitivity (Se) and specificity (Sp) of each protocol was estimated using latent class models. The PCR protocols were more sensitive (Se > 0.97) than microscopy (Se = 0.53) giving a prevalence of infection of 17–18%, twice as high as microscopy. Microscopy may not be as specific as PCR if Trypanosomatid-like organisms make up a high proportion of the sample. For small T. infestans, microscopy is not efficient, giving a prevalence of 1.5% when PCR techniques gave 10.7%. The PCR techniques were in agreement (Kα = 0.94) but not with microscopy (Kα never significant with both PCR techniques). Among the PCR protocols, the MeM-PCR was the most efficient (Se=1; Sp=1).
Triatomine vectors are responsible for the main route of transmission of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. This illness is potentially life-threatening and highly disabling and represents a major public health concern in the endemic countries in Latin America. The analysis of the spatial and temporal occurrence of triatomine insects is critical, since control strategies strongly depend on the vector species found within each area. Such knowledge is non-existent in Hidalgo state, an endemic region of Chagas disease in Mexico. A Geographic Information System (GIS) was used to analyze broad-scale spatial and temporal patterns of synanthropic triatomines collected in Hidalgo. Data was taken from the Institute of Epidemiological Diagnosis and Reference (InDRE) of Mexico and the state program of Vector Control of the Secretary of Health, covering the period of 1997-2019. Our analyses demonstrate a differential distribution of Triatoma dimidiata, T. mexicana, T. gerstaeckeri and T. barberi, which are the four predominant species, and that climate, temperature, and precipitation are some of the drivers of their distribution pattern. Notably, we report the presence of T. nitida, T. pallidipennis and T. phyllosoma for the first time in the state. In addition, we found seasonal variations of the populations of T. mexicana and T. gerstaeckeri, but not for T. dimidiata, whose population remains constant throughout the year. The insects were found mainly intradomicile (81.79 %), followed by peridomicile (17.56 %) and non-domestic areas (0.65%), with an average T. cruzi infection of 16.4%. Based on this evidence, priority sites for vector control intervention were identified. Our findings are very valuable for understanding the epidemiology of Chagas disease, the generation of future potential risk maps and for the development and implementation of effective and targeted vector control programs in Hidalgo state.
The present paper reports new distribution records of Triatoma gerstaeckeri (Stål) in the municipalities of China, General Bravo, Santiago and Villaldama of the state of Nuevo León; whereas Triatoma rubida (Uhler) is reported for the first time in the municipality of Ocampo of the state of Coahuila, México.
Numerous scientists have emphasized the importance of phylogenetic information in ecosysteic interrelations, population dynamics, and possibilities for control when such populations are harmful to human beings and their health and economy. This work questioned at one and the same time the Henning's theory which considers that the unit of study is not the species or the individual but rather each one of his different periods of evolution called semaphoront, and the definition of species according to Mayr et al. (1953) : "groups of natural populations that reproduce within each other in a real or potential way and that are isolated reproductively from other analogous groups". These concepts should be interpreted taking into account not only the biological and genetic but also the geographical and ecological isolation. So exist in the nature many species perfectly identified by morphology able to cross and give fertile hybrids, sometimes with rapid fixation of new intermediate characters, that might be considered as new species by hybridization. This is well known by farmers and breeders of orchideae and aquarium fishes. Among Triatominae, the most noteworthy example may be that of #Triatoma infestans$ which produces fertile offsprings with #T. platensis$ over several generations. Hybrid forms present morphological intermediate characters between both species after many years. All Hemiptera Heteroptera feed by sucking organic liquids. According to the food-seeking trends, Schofield (1995) divides them into several groups : the Leptopodomorpha feed on the ground surface ; the Gerromorpha on the water surface monocuticle ; the Nepomorpha below water ; and three categories, Enicocephalomorpha, Dipsocoromorpha and Cimicomorpha, in interstitial habitats... (D'après résumé d'auteur)
From August 1997 to August 1998, 334 specimens of Triatoma longipennis and 62 of T. picturata were collected in four groups of localities placed in the zone from Guadalajara, Jalisco to Tepic, Nayarit, in the West Coast of Mexico. Most T. longipennis were collected outdoors (69.2%) while most T. picturata (58.1%) were collected indoors. All collected specimens were examined for Trypanosoma cruzi infection, which was detected on 98 (29.3%) T. longipennis and 17 (27.4%) T. picturata. This study confirms the role of T. longipennis and T. picturata as some of the main T. cruzi vectors to humans in Mexico. Habitation Infestation Rate with T. longipennis was of 0.09 and with T. picturata was of 0.03 and the predominating ecotopes were pile of blocks, chicken coops, pigsties, wall crawls and beds.
The complete life cycle of Triatoma flavida, weekly fed on hens, was studied at 28+/-2 degrees C and 80+/-10% RH. Aspects related to hatching, life span, mortality and feeding behavior for each stage of its life cycle were evaluated. The hatching rate observed for 100 eggs was 93% with an average incubation period of 27.2 days. Sixty-two nymphs completed the cycle and the mean egg to adult development time was 230.4 days. Mean duration of 1st, 2nd, 3rd, 4th and 5th instar nymphs was 22.1, 25.3, 36.7, 49.7 and 69.4 days, respectively. The number of blood meals on each nymphal stage varied from 1 to 7. The mortality rate was 6.5% for NI, 23% for NIII and 7.5% for NV nymphs. Mean number of laid eggs per female was 283.1. Adult survival rates were 344.8 +/- 256.4 days for males and 285.3 +/- 201.8 days for females.
With the purpose of evaluating the risk of transmission of the Chagas disease in the State of Colima, México, an entomological survey was performed to obtain triatominae and the rate of infection by Trypanosoma cruzi determined by examination of its dejections. Two hundred eighteen houses located in 16 villages were sampled. In each house the intradomestic and peridomestic habitats were examined by the man-hour-house method, sensor boxes and mouse-baited traps. Also, 12 silvatic places were explored around the same areas using the same techniques as the ones sampled. In total, 456 specimens were captured, of which 139 correspond to Triatoma phyllosoma pallidipennis; 80 to T.p. longipennis; one specimen of T. dimidiata and 236 nymphs of Triatoma sp. Two hundred ninety seven insects were captured in the intradomestic habitat, 132 in the peridomestic and 26 in the silvatic. The index of positive houses was 27%, located in the central area of the state. The rate of natural infection with T. cruzi showed 25.6%. This results confirmed the presence of two important vectors of the Chagas disease in Colima. Its preference for the domestic habitat and its high levels of natural infection with T. cruzi suggested the existence of a significant risk for its transmission in this area of the country.
Morpho-biological diversity of Trypanosoma cruzi has been known since Chagas' first works in 1909. Several further studies confirmed the morphological differences among the parasite strains, which were isolated from different reservoirs and vectors, as well as from human beings. In the early sixties, antigenic differences were found in the parasite strains from various sources. These differences, coupled to the observation of regional variations of the disease, led to the proposal of the term cruzi complex to designate the taxon T. cruzi. Since then this protozoan has been typed in distinct biodemes, zymodemes and lineages which were consensually grouped into T. cruzi I, T. cruzi II and into non-grouped strains. T. cruzi genotypic characterization, initially carried out by schizodeme analysis and more recently by various other techniques, has shown a great diversity of the parasite strains. In fact, T. cruzi is formed by groups of heterogeneous sub-population, which present specific characteristics, including distinct histotropism. The interaction of the different infecting clones of the cruzi complex and the human host will determine the morbidity of the disease.
The detection of infestations of Triatominae in houses in regions endemic for Chagas's disease is a criterion frequently used in the selection of areas, or of individual houses, for treatment in insecticide campaigns as well as in the evaluation of insecticide performance.
Several different methods for detecting domestic infestations with Triatominae were compared: night capture, capture of live bugs with the aid of a flushing-out agent and use of card boxes of the Gómez-Núñez type. The flushing-out and Gómez-Núñez box methods were found to be equally sensitive, although each failed to detect some infestations which the other detected. The night capture method was slightly more sensitive but was found to be impractical for insecticide trials. Improvement to the flushing-out method, notably the introduction of a systematic search technique, made it much more sensitive than the Gómez-Núñez box method for heavily infested houses and for houses three months after insecticide treatment.
Although the sensitivity of the Gómez-Núñez box method increases when the boxes are left in place for a long time, this also limits the value of the information obtained regarding the evaluation of insecticides. On the basis of the results presented, the flushing-out method using a systematic search of the house was found to be the most suitable sampling technique, but it is recognized that this method still has limitations.
We performed a transversal-type epidemiological study in the state of Morelos, Mexico, to determine the presence of triatomines, their ecotopes, and importance in transmission of Trypanosoma cruzi Chagas. Sampling sites included domestic, peridomestic, and wild areas with collection based on the person per hour technique. We determined the entomological indices related to infestation, density, overcrowding, colonization, infection, and dispersion, which were used to calculate transmission risk. During the study, observations were made on the predominant building material, presence of cracks and illumination as factors fostering colonization. The most important results were related to infection indices, which were higher for domestic type triatomines (29%), whereas it was 4% for peridomestic sites, and 20% for sylvatic areas. The actual risk of human contact with the vector was of 0.51%, and the predominating ecotopes were stone heaps.