Blood meal sources of wild and domestic Triatoma infestans (Hemiptera: Reduviidae) in Bolivia: connectivity between cycles of transmission of Trypanosoma cruzi.

Background: Chagas disease is a major public health problem in Latin America. Its etiologic agent, Trypanosoma cruzi, is mainly transmitted through the contaminated faeces of blood-sucking insects called triatomines. Triatoma infestans is the main vector in various countries in South America and recently, several foci of wild populations of this species have been described in Bolivia and other countries.

Putative panmixia in restricted populations of Trypanosoma cruzi isolated from wild Triatoma infestans in Bolivia.

Trypanosoma cruzi, the causative agent of Chagas disease, is subdivided into six discrete typing units (DTUs; TcI-TcVI) of which TcI is ubiquitous and genetically highly variable. While clonality is the dominant mode of propagation, recombinant events play a significant evolutive role. Recently, foci of wild Triatoma infestans have been described in Bolivia, mainly infected by TcI.

Wild populations of Triatoma infestans are highly connected to intra-peridomestic conspecific populations in the Bolivian Andes.

Triatoma infestans, the major vector of Chagas disease south of the Amazon in South America, has a large distribution of wild populations, contrary to what has previously been stated. These populations have been suspected of being the source of reinfestation of human habitats and could impede the full success of vector control campaigns. This study examined gene flow between intra-peridomestic populations and wild populations collected in the surround areas in three Andean localities in Bolivia.

Risk of transmission of Trypanosoma cruzi by wild Triatoma infestans (Hemiptera: Reduviidae) in Bolivia supported by the detection of human blood meals.

We analyzed the food sources of Bolivian wild Triatoma infestans (the main vector of Chagas disease in this country), to assess the role of these populations in the epidemiological context of Chagas disease. Ninety-eight blood meals were identified by heteroduplex assay and sequencing. Most of them were from wild mammals but surprisingly 27 were from humans.

Combination of cytochrome b heteroduplex-assay and sequencing for identification of triatomine blood meals.

The identification of blood meals in vectors contributes greatly to the understanding of interactions between vectors, microorganisms and hosts. The aim of the current work was to complement the validation of cytochrome b (Cytb) heteroduplex assay (HDA) previously described, and to add the sequencing of the Cytb gene of some samples for the identification of blood meals in triatomines. Experimental feedings of reared triatomines helped to clarify the sensitivity of the HDA.

Trypanosoma cruzi discrete typing units (DTUs): microsatellite loci and population genetics of DTUs TcV and TcI in Bolivia and Peru.

Trypanosoma cruzi, the agent of Chagas disease, is usually subdivided into six discrete typing units (DTUs), TcI to TcVI, among which TcI and TcV are most common in human infections in Bolivia. Multilocus microsatellite typing (MLMT) was selected to further explore the structure of the natural populations belonging to these DTUs. The analysis showed that microsatellite clustering does not fully match the six DTUs, but it is relevant for the within DTUs analyses.

New insights on the Chagas disease main vector Triatoma infestans (Reduviidae, Triatominae) brought by the genetic analysis of Bolivian sylvatic populations.

Triatoma infestans is the main and most widespread vector of Chagas disease in South America. For the first time, a large sample of sylvatic populations of T. infestans was analyzed by ITS-2 and mtCytB sequencing.

Community participation and domiciliary occurrence of infected Meccus longipennis in two Mexican villages in Jalisco state.

The entomological features of Chagas disease in two western Mexican villages were analyzed through triatomines collection by the inhabitants and active research in the peridomicile. The inhabitant collections have the following comparable characteristics: 1) Meccus longipennis was the dominant species (> 91%), 2) around 43% of the insects were collected indoors, 3) about 70% of triatomines were adults, 4) cumulated rates of infestation of the dwellings reached 40-50%, 5) the triatomine infection rate by Trypanosoma cruzi was > 50%, and 6) the indoor triatomines frequently feed on humans (range 38.5-56.

First report of widespread wild populations of Triatoma infestans (Reduviidae, Triatominae) in the valleys of La Paz, Bolivia.

Wild populations of Triatoma infestans, the main vector of Chagas disease in the Southern Cone countries, may be involved in reinfestation of human dwellings, limiting the success of vector-control campaigns in Bolivia. Knowledge of the distribution of these populations remains incomplete. We report here the detection of T.

Wild ecotopes and food habits of Triatoma longipennis infected by Trypanosoma cruzi lineages I and II in Mexico.

The control of wild triatomine populations that can invade dwellings is a major challenge for Chagas disease control in Mexico, but a better knowledge of the biology of these populations is required to develop appropriate control methods. We describe a new terrestrial ecotope of Triatoma longipennis, a principal vector in the occidental part of Mexico, in addition to its previously identified niche in rock pile boundary walls. Analysis of feeding hosts in the two ecotopes showed that this species is able to diversify its food sources outside of the principal hosts, Dasypus novemcinctus and Procyon lotor, and to disperse in search of new meals.

[Epidemiologic knowledge and current situation of Chagas disease in the state of Jalisco, Mexico].

Chagas disease in the state of Jalisco, Mexico was described for the first time in 1967; however, knowledge on the disease remains in a slow process. Between 1967 and 2006, the disease was described in its acute and chronic forms. The vector species have been identified, and the parasite Trypanosoma cruzi has been isolated and genetically characterized.

Exploring the FL-160-CRP gene family through sequence variability of the complement regulatory protein (CRP) expressed by the trypomastigote stage of Trypanosoma cruzi.

The complement regulatory protein (CRP) of Trypanosoma cruzi is a surface glycoprotein which confers to the infectious trypomastigote forms a protection against the lytic activity of the host complement. CRP belongs to the large family of the trans-sialidase-like proteins and its sequence is highly similar to those of the flagellar FL-160 and chronic exoantigen proteins, encoded by a multigene family. To further define the gene family encoding the CRP, we investigated the protein diversity among several strains of T.

Sequence diversity and differential expression of Tc52 immuno-regulatory protein in Trypanosoma cruzi: potential implications in the biological variability of strains.

Trypanosoma cruzi is highly heterogeneous in terms of genetics and biological properties. To explore the diversity of T. cruzi, we focused our study on the T.

Genetic clustering of Trypanosoma cruzi I lineage evidenced by intergenic miniexon gene sequencing.

American trypanosomiasis or Chagas disease is endemic in Latin America and caused by the flagellate Trypanosoma cruzi, which exhibits broad genetic variation. In various areas, the transmission of Chagas disease is ensured by sylvatic vectors, mainly carrying the evolutionary lineage I of T. cruzi.

Peridomestic colonization of Triatoma longipennis (Hemiptera, Reduviidae) and Triatoma barberi (Hemiptera, Reduviidae) in a rural community with active transmission of Trypanosoma cruzi in jalisco state, Mexico.

Infestation of peridomiciles is likely a major risk factor for Chagas disease transmission in Jalisco state, Mexico. An entomological and serological survey of a typical village was conducted between July and September 2003. The peridomestic areas of 100 dwellings were visited and triatomines were searched manually in 369 potential sites.

Peridomicilary habitat and risk factors for Triatoma infestation in a rural community of the Mexican occident.

An examination of peridomestic area organization and triatomine collection in an endemic village for Chagas disease (Jalisco State) identified the habitat of Triatoma longipennis (dominant species) and the risk factors of peridomestic infestation. In 100 visited peridomestic areas, 369 structures (permanent, temporary, and natural) were submitted to active manual research of triatomines. Storage shelters had a higher infestation of T.

Detection of Chagas infections using Trypanosoma evansi crude antigen demonstrates high cross-reactions with Trypanosoma cruzi.

Antigenic similarities between salivarian trypanosomes are known for a long time, but similarities between salivarian and stercorarian trypanosomes have been very little investigated. Phylogenetically, these genus and species appear to be far. However, in a preliminary work we had shown strong reactions of chagasic human sera using T.

Polymerase chain reaction detection and serologic follow-up after treatment with benznidazole in Bolivian children infected with a natural mixture of Trypanosoma cruzi I and II.

Thirty-five Bolivian children (5-10 years of age) seropositive for infection with T. cruzi underwent specific chemotherapy with benznidazole. Before treatment, 57.

Epidemiological risk for Trypanosoma cruzi transmission by species of Phyllosoma complex in the occidental part of Mexico.

Domestic and peridomestic triatomine populations were collected in three rural Mexican communities of Jalisco, Nayarit and Zacatecas states. Triatoma longipennis and T. picturata (Phyllosoma complex) were the principal species unequally distributed in the villages: T.

Identification in triatomine vectors of feeding sources and Trypanosoma cruzi variants by heteroduplex assay and a multiplex miniexon polymerase chain reaction.

Feeding sources of triatomine vectors (Triatoma longipennis) collected in peridomiciles in Mexico were identified by a heteroduplex assay developed with triatomine blood meals. Trypanosoma cruzi parasites were also characterized in the same blood meal samples by multiplex-polymerase chain reaction assay of mini-exon gene inter-genic regions. The main blood meal source was from rats, but the bugs were able to feed on a wide variety of hosts, and human blood meals were identified.

Feeding patterns of Triatoma longipennis Usinger (Hemiptera, Reduviidae) in peridomestic habitats of a rural community in Jalisco State, Mexico.

We analyzed triatomine blood feeding patterns to evaluate the role of peridomiciles in Trypanosoma cruzi transmission at the rural village of Tepehuaje de Morelos at Jalisco State, Mexico (1999). A total of 206 bugs were collected in 11 out of 26 households (42.3%).

Colonization of rock pile boundary walls in fields by sylvatic triatomines (Hemiptera: Reduviidae) in Jalisco State, Mexico.

Granite rocks is a very abundant material in Mexico because they are used habitually as borders for fields. The current work established the significance of this ecotype as a colonization site for triatomines of the Phyllosoma complex. Seven sites, arbitrary selected, in San Martin de Hidalgo municipality (Mexico) were investigated in April 2002 by using 210 mouse bait-traps left during the night in wall hollows.

Preliminary results of random amplification of polymorphic DNA among Triatominae of the phyllosoma complex (Hemiptera, Reduviidae).

In Mexico, Triatoma longipennis (Usinger), Triatoma picturata (Usinger), and Triatoma pallidipennis (Stal), primary Chagas disease vector species of the phyllosoma complex, were analyzed by randomly amplified polymorphic DNA (RAPD). Sixteen decametric primers resolved individual profiles not identical, but partially discriminative between species. Analysis based on pairwise presence/absence comparisons between the three species was performed using three primers and two outgroup species Triatoma infestans (Klug) and Triatoma barberi (Usinger).

Trypanosoma cruzi carrying a targeted deletion of a Tc52 protein-encoding allele elicits attenuated Chagas' disease in mice.

The intracellular protozoan parasite Trypanosoma cruzi is the etiological agent of Chagas' disease. We have previously characterized a T. cruzi virulence factor named Tc52 sharing structural and functional properties with the thioredoxin and glutaredoxin protein family.