RESUMO
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi (Chagas, 1909). One of the primary vectors of T. cruzi in South America is Triatoma infestans (Klug, 1834). This triatomine species is distributed across a huge latitudinal gradient, inhabiting domiciliary , peridomiciliary , and wild environments. Its wide geographic distribution provides an excellent opportunity to study the relationships between environmental gradients and intraspecific morphological variation. In this study, we investigated variations in wing size and shape in T. infestans across six ecoregions. We aimed to address the following questions: How do wing size and shape vary on a regional scale, does morphological variation follow specific patterns along an environmental or latitudinal gradient, and what environmental factors might contribute to wing variation? Geometric morphometric methods were applied to the wings of 162 females belonging to 21 T. infestans populations, 13 from Argentina (n = 105), 5 from Bolivia (n = 42), and 3 from Paraguay (n = 15). A comparison of wing centroid size across the 21 populations showed significant differences. Canonical Variate Analysis (CVA) revealed significant differences in wing shape between the populations from Argentina, Bolivia, and Paraguay, although there was a considerable overlap, especially among the Argentinian populations. Well-structured populations were observed for the Bolivian and Paraguayan groups. Two analyses were performed to assess the association between wing size and shape, geographic and climatic variables: multiple linear regression analysis (MRA) for size and Partial Least Squares (PLS) regression for shape. The MRA showed a significant general model fit. Six temperature-related variables, one precipitation-related variable, and the latitude showed significant associations with wing size. The PLS analysis revealed a significant correlation between wing shape with latitude, longitude, temperature-related, and rainfall-related variables. Wing size and shape in T. infestans populations varied across geographic distribution. Our findings demonstrate that geographic and climatic variables significantly influence T. infestans wing morphology.
Assuntos
Triatoma , Asas de Animais , Animais , Triatoma/anatomia & histologia , Triatoma/fisiologia , Triatoma/crescimento & desenvolvimento , Triatoma/classificação , Asas de Animais/anatomia & histologia , Feminino , Argentina , Bolívia , Paraguai , Doença de Chagas/transmissãoRESUMO
The Triatoma brasiliensis species complex is a monophyletic group encompassing two subspecies and six species. Recently, a hybrid zone of members of this complex was recorded in the state of Pernambuco. Questions concerning the capability of the hybrids to become infected with Trypanosoma cruzi have been raised. This study aimed to compare the susceptibility of Triatoma b. brasiliensis, Triatoma juazeirensis, and their experimental hybrids to infection with T. cruzi. We infected the parentals and their experimental hybrids (obtained through reciprocal crosses) through artificial feeding with citrated rabbit blood, to which the TcI 0354 strain of T. cruzi had been added. The insects were weighed before and after feeding on the rabbit blood, and then they were dissected on the 10th, 20th, and 30th day after infection. Both the hybrids and the parentals remained infected throughout the experiment. The parasite was mostly found in the epimastigote form. The number of epimastigotes was significantly lower in the stomach and small intestine of T. juazeirensis than in the hybrids or in T. b. brasiliensis. A significantly higher percentage of metacyclic trypomastigotes was detected in the small intestine and rectum of the hybrids. Hybrids demonstrated higher susceptibility to the TcI 0354 strain than their parentals, opening up new avenues to be investigated.
RESUMO
Triatoma costalimai and Triatoma jatai are related species, which occur in sympatry in Paranã, Tocantins, Brazil, in rocky outcrops and in peridomicile and intradomicile environments. This study compared morphologic and morphometric aspects of the eggs of these species using optical microscopy (OM) and scanning electron microscopy (SEM). Operculum cells (OP) and egg body (EB) were drawn and photographed, their surfaces were measured, and spots were quantified. Statistical analyses were performed using ANOVA and t-tests. OM showed an egg exochorium with spots in T. costalimai and a predominance of short lines in T. jatai. We found significant differences in egg length and width, which were larger in T. costalimai. SEM analysis showed that the operculum of both species had cells with straight and/or rounded rims, with a smooth aspect, random spots, and predominantly pentagonal shape. In the EB, hexagonal cells were predominant, with indices exceeding 60% in both species. Triatoma costalimai cells were flat, with a discrete definition of the rims, whereas T. jatai cells were smooth with well-defined rims. Statistical tests showed significant differences for EB, where T. costalimai cells were larger and have more spots than T. jatai. The eggs can thus be differentiated, thereby contributing to integrative taxonomy.
Assuntos
Doença de Chagas , Triatoma , Triatominae , Animais , Simpatria , Microscopia Eletrônica de Varredura , BrasilRESUMO
An outbreak of Chagas disease, possibly involving its vector Triatoma brasiliensis brasiliensis, was identified in the state of Rio Grande do Norte (RN). Given the historical significance of this vector in public health, the study aimed to evaluate its role in the transmission dynamics of the protozoan Trypanosoma cruzi in an area undergoing desertification in the Seridó region, RN, Brazil. We captured triatomines in sylvatic and anthropic ecotopes. Natural vector infection was determined using parasitological and molecular methods and we identified discrete typing units (DTUs) of T. cruzi by analyzing the COII gene of mtDNA, 24Sα rDNA, and mini-exon gene. Their blood meals sources were identified by amplification and sequencing of the mtDNA cytochrome b gene. A total of 952 T. b. brasiliensis were captured in peridomestic (69.9%) and sylvatic ecotopes (30.4%). A wide range of natural infection rates were observed in peridomestic (36.0% - 71.1%) and sylvatic populations (28.6% - 100.0%). We observed the circulation of TcI and TcII DTUs with a predominance of Tcl in sylvatic and peridomestic environments. Kerodon rupestris, rocky cavy (13/39), Homo sapiens, human (8/39), and Bos taurus, ox (6/39) were the most frequently detected blood meals sources. Thus, Triatoma b. brasiliensis is invading and colonizing the human dwellings. Furthermore, high levels of natural infection, coupled with the detection of TcI and TcII DTUs, and also the detection of K. rupestris and H. sapiens as blood meals sources of infected T. b. brasiliensis indicate a risk of T. cruzi transmission to human populations in areas undergoing desertification.
Assuntos
Doenças dos Bovinos/transmissão , Doença de Chagas/transmissão , Doença de Chagas/veterinária , Insetos Vetores/fisiologia , Triatoma/parasitologia , Trypanosoma cruzi/fisiologia , Zoonoses/transmissão , Animais , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Comportamento Alimentar , Feminino , Humanos , Insetos Vetores/parasitologia , Masculino , Triatoma/fisiologia , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificação , Zoonoses/epidemiologia , Zoonoses/parasitologiaRESUMO
BACKGROUND: Chagas Disease (CD) affects 6-7 million people worldwide and is related to poverty-promoting conditions. Chronic asymptomatic cases are mostly invisible to health systems. Aiming (1) to translate CD discoveries into education/information practices to raise alertness and empowerment of affected people; and (2) to perform an active search of CD cases, articulating intersectoral actions to improve the access of infected people to the local health service for the treatment of CD; our research group developed and tested under field conditions as innovative social technology: an itinerant education interdisciplinary setting named "Chagas Express XXI" (CE21). METHODOLOGY: CE21 was created as an "imaginary train" with ~40 ArtScience workshops, games, laboratory activities and conversation circles. An entry/exit plus six activity modules combined associations of affected people, microscopic observations, One Health education, and wellness activities. CE21 was conceived as a social technology, since all the processes were co-created with CD patients and inter-sector local partners. Descriptive statistics showed quantitative data collected throughout the expeditions (CD knowledge, serological results). Qualitative data accessed the public perceptions about the education activities. PRINCIPAL FINDINGS: CE21 was exhibited in local educational institutions (schools, universities) in four cities, engaging 2,117 people that evaluated the 41 activities carried out. Citizens and health professionals enjoyed acquisition of information related to blood, parasites, vectors, reservoirs, environmental changes, and social determinants of CD. Further, local legacies of 600 participants volunteer for health promotion groups and CD associations, local empowerment groups to fight for better health conditions, and 05 mural paintings. We observed that 81% of the participants ignored the possibility of treating CD while 52% of the participants requested a blood test for CD showing seropositivity in 20% of them. CONCLUSIONS: CE21 is a social technology potentially useful for health and science education and active search of asymptomatic CD chronic cases. Moreover, this technology may be adapted to understand and to cooperate in other potentially epidemic situations, especially NTDs related.
Assuntos
Doença de Chagas/epidemiologia , Educação em Saúde , Promoção da Saúde/métodos , Ciência/educação , Adulto , Idoso , Brasil/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tecnologia , Adulto JovemRESUMO
Extracellular adenosine plays important roles in modulating the immune responses. We have previously demonstrated that infection of dendritic cells (DC) by Leishmania amazonensis leads to increased expression of CD39 and CD73 and to the selective activation of the low affinity A2B receptors (A2B R), which contributes to DC inhibition, without involvement of the high affinity A2A R. To understand this apparent paradox, we now characterized the alterations of both adenosine receptors in infected cells. With this aim, bone marrow-derived DC from C57BL/6J mice were infected with metacyclic promastigotes of L. amazonensis. Fluorescence microscopy revealed that L. amazonensis infection stimulates the recruitment of A2B R, but not of A2A R, to the surface of infected DC, without altering the amount of mRNA or the total A2B R density, an effect dependent on lipophosphoglycan (LPG). Log-phase promastigotes or axenic amastigotes of L. amazonensis do not stimulate A2B R recruitment. A2B R clusters are localized in caveolin-rich lipid rafts and the disruption of these membrane domains impairs A2B R recruitment and activation. More importantly, our results show that A2B R co-localize with CD39 and CD73 forming a "purinergic cluster" that allows for the production of extracellular adenosine in close proximity with these receptors. We conclude that A2B R activation by locally produced adenosine constitutes an elegant and powerful evasion mechanism used by L. amazonensis to down-modulate the DC activation.
Assuntos
5'-Nucleotidase/metabolismo , Antígenos CD/metabolismo , Apirase/metabolismo , Caveolina 1/metabolismo , Células Dendríticas/imunologia , Leishmaniose/imunologia , Microdomínios da Membrana/imunologia , Receptor A2B de Adenosina/metabolismo , Animais , Células Dendríticas/metabolismo , Células Dendríticas/parasitologia , Células Dendríticas/patologia , Imunidade , Imunomodulação , Leishmania/imunologia , Leishmaniose/metabolismo , Leishmaniose/parasitologia , Leishmaniose/patologia , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/parasitologia , Macrófagos/patologia , Masculino , Microdomínios da Membrana/parasitologia , Microdomínios da Membrana/patologia , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Morphology of cimicid eggs are scarce, and this is the first record for the genus Ornithocoris Pinto, 1927 (Hemiptera: Cimicidae), using scanning electron microscopy (SEM). This genus comprises two species: Ornithocoris toledoi Pinto, 1927 (Hemiptera: Cimicidae) and Ornithocoris pallidus (Usinger, 1959). The eggs of O. pallidus are ellipsoid, and an evident 'lateral flattening', which may give clear asymmetry from the longitudinal axis. The exochorion of the body of the egg and operculum of O. pallidus present spherical or polygonal structures in relief, and pseudomicropyles on the border of the operculum, both differing from Cimex lectularius. The internal face of the operculum is smooth and the border also presented three layers. It was not possible to observe micropyles in the egg of O. pallidus. Bed bugs have a great psychological impact on people, and some people can develop a more or less severe allergic reaction against the bite. Successful control of bed bugs needs serious organization. Studies on egg morphology will add more information to assist in taxonomy studies of O. pallidus and can serve as a basis for control studies because eggs are resistant to insecticides.
Assuntos
Cimicidae/ultraestrutura , Animais , Cimicidae/crescimento & desenvolvimento , Microscopia Eletrônica de Varredura , Óvulo/crescimento & desenvolvimento , Óvulo/ultraestruturaRESUMO
BACKGROUND: Taxonomic identification of triatomines is generally performed based on aspects of their external morphology. However, the use of a multidisciplinary approach, considering morphological aspects of the external genitalia, morphometry, genetics, and phylogeography has been suggested, especially for similar and/or cryptic species. The rupestral species Triatoma jatai Gonçalves et al., 2013, Triatoma costalimai Verano & Galvão, 1959 and Triatoma williami Galvão et al., 1965, which are morphologically similar, have been found naturally infected with Trypanosoma cruzi (Chagas, 1909) in wild, peridomestic, and intradomestic environments, representing a risk of new outbreaks of Chagas disease. This study presents morphological description complementation of these species, with an emphasis on the structures of the female external genitalia, using scanning electron microscopy. METHODS: The females of T. jatai and T. costalimai (n = 10 of each) were captured in the Brazilian municipalities of Paranã and Aurora do Tocantins and were identified with the use of a dichotomous key for the Matogrossensis subcomplex. Females of T. williami (n = 5), were obtained from a laboratory colony. The females were cut transversely at the sixth abdominal segment and examined under scanning electron microscopy (SEM) at the Oswaldo Cruz/Fiocruz Institute Electronic Microscopy Platform. RESULTS: It was possible to differentiate the three species based on the characteristics of urotergites VII, VIII and IX and urosternite VII, as well as the genital plaques, gonocoxites, and gonapophyses. To our knowledge, morphological differences in the spines present on gonapophysis 8 in triatomines are described here for the first time. CONCLUSIONS: The results show that external genitalia of females are useful structures to differentiate T. costalimai, T. jatai and T. williami. SEM analysis contributes to and corroborates, together with other tools morphological and molecular, the distinction of the three species.
Assuntos
Genitália Feminina/ultraestrutura , Triatoma/anatomia & histologia , Triatoma/classificação , Animais , Brasil , Feminino , Microscopia Eletrônica de VarreduraRESUMO
BACKGROUND: In Brazil, Triatoma maculata is only found in the State of Roraima and is a vector of Trypanosoma cruzi, the etiological agent of Chagas disease. It occurs in wild, peridomestic and domestic habitats, with an urban infestation in Boa Vista, the capital of this Brazilian state. The aim of this study was to assess the morphological variability of the T. maculata antennal phenotype in three populations of Roraima State, using the antennal sensilla pattern analyzed under optical microscopy. METHODS: The number and distribution of four antennal sensilla types (bristles, thin and thick walled trichoidea, and basiconic) of three Brazilian populations of T. maculata from Roraima State were compared. Univariate and multivariate analyses were performed. RESULTS: The antenna of T. maculata presented the four types of sensilla. According to the density and distribution of the antennal sensilla characteristics, the multivariate analyses showed that the laboratory population is morphologically structured. Urban specimens showed a pronounced phenotypic variability. The main differences were observed in the pedicel segment, and between males and females. CONCLUSIONS: We determined the antennal phenotype in three Roraima populations of T. maculata. These results support the idea that the patterns of antennal sensilla are sensitive markers for distinct populations in the Triatominae. The infestations of T. maculata in different habitats reinforces the ability of this vector to become adapted to a variety of environments, which, could have eco-epidemiological implications for the T. cruzi transmission that are still not well understood.
Assuntos
Variação Biológica da População , Insetos Vetores/anatomia & histologia , Triatoma/anatomia & histologia , Distribuição Animal , Animais , Feminino , Insetos Vetores/fisiologia , Masculino , Densidade Demográfica , Sensilas/anatomia & histologia , Triatoma/fisiologiaRESUMO
Reliable data on distributional ranges of soft ticks (Argasidae) and assessments of putative tick-borne agents enhance the understanding on tick-associated microorganisms. A total of 96 ticks morphologicaly and molecularly identified as Ornithodoros rietcorreai were collected in Tocantins State, Brazil, using Noireau traps with living bait as CO2 source. Ninety-six ticks (54 nymphs, 32 males, 10 females) with different engorgement degrees were collected. Fourty-seven (48.9%) of them were individually screened by PCR for detecting bacteria of Anaplasmataceae family and genera Rickettsia, and Borrelia. The presence of protozoans of the genus Babesia was assessed as well. Fourty seven ticks were submitted to analysis. Nine ticks (19.1%) yielded sequences for gltA and htrA genes most identical with a series of endosymbiont rickettsiae and Rickettsia bellii, respectively. Upon two ticks (4.2%) we retrieved DNA of a potential new Wolbachia sp., and DNA of a putative novel Hepatozoon was characterized from three (6.4%) specimens. No DNA of Babesia or Borrelia was detected. Remarkably, amplicons of unidentified eukaryotic organisms, most closely related with apicomplexans but also with dinoflagellates (91% of identity after BLAST analyses), were recovered from two ticks (4.2%) using primers designed for Babesia 18S rRNA gene. Our records expand the distribution of O. rietcorreai into Brazilian Cerrado biome and introduce the occurrence of microorganisms in this tick species.
Assuntos
Bactérias/genética , Ornithodoros/microbiologia , Ornithodoros/parasitologia , Filogenia , Anaplasmataceae/genética , Anaplasmataceae/isolamento & purificação , Animais , Babesia/genética , Babesia/isolamento & purificação , Bactérias/isolamento & purificação , Borrelia/genética , Borrelia/isolamento & purificação , Brasil , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Feminino , Geografia , Larva/microbiologia , Masculino , Ninfa/microbiologia , Rickettsia/genética , Rickettsia/isolamento & purificaçãoRESUMO
The rupestrian Triatoma costalimai species has been found infected by Trypanosoma cruzi in wild, peridomicile, and intradomicile environments in the municipality of Aurora do Tocantins, Tocantins, Brazil. Proximity between rock outcrops increases the risk of vector transmission of Chagas disease via this species. This work describes a focus of colonization by T. costalimai specimens infected by T. cruzi in rock outcrops located in an urban area in this municipality. Parasitological examination of feces from the collected specimens, axenic cultivation of T. cruzi-positive samples, and genetic characterization of the isolates were performed. Nymph and adult specimens were collected with a high infection prevalence (64.5%) for T. cruzi discrete type unit (DTU I). Participation of the T. costalimai species in the wild cycle of T. cruzi in rock outcrops located in an urban area demonstrates the need for entomological surveillance and control of vector transmission of Chagas disease in the municipality of Aurora do Tocantins, Tocantins.
Assuntos
Doença de Chagas/parasitologia , Insetos Vetores/parasitologia , Triatoma/parasitologia , Trypanosoma cruzi/genética , Animais , Animais Domésticos/parasitologia , Cultura Axênica , Brasil , Fezes/parasitologia , Genótipo , Ninfa/parasitologia , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
INTRODUCTION: Chagas disease is caused by the protozoa Trypanosoma cruzi. Its main reservoir is the domestic dog, especially in rural areas with favorable characteristics for vector establishment and proliferation. The aims of this study were to collect data, survey and map the fauna, and identify T. cruzi infection in triatomines, as well as to assess the presence of anti-T. cruzi antibodies in dogs in rural areas of the municipality of Mossoró, Brazil. METHODS: An active entomologic research was conducted to identify adult specimens through an external morphology dichotomous key. The analysis of natural infection by T. cruzi in the insects was performed by isolation in culture and polymerase chain reaction. The antibody testing for T. cruzi in dogs was performed by enzyme-linked immunosorbent assay and indirect immunofluorescence assay. RESULTS: A total of 68 triatomines were captured, predominantly the Triatoma brasiliensis brasiliensis (Neiva 1911) species. The vector mapping displayed areas with greater risk for parasite transmission. Of the examined triatomines (51 specimens), 41.2% (21/51) were positive on polymerase chain reaction, and all were negative on culture. In the serum testing, 11% (25/218) of dogs were seropositive, but no association was found between the serologic results and the presence and infection by T. cruzi in triatomines. CONCLUSIONS: This study demonstrated the movement of T. cruzi in the studied area, by the presence of vectors and naturally infected domestic reservoirs. The mapping of the studied rural area demonstrates the risk of disease transmission.
Assuntos
Anticorpos Antiprotozoários/sangue , Doença de Chagas/veterinária , Doenças do Cão/diagnóstico , Insetos Vetores/parasitologia , Triatominae/parasitologia , Trypanosoma cruzi/imunologia , Animais , Brasil/epidemiologia , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Doenças do Cão/epidemiologia , Cães , Técnica Indireta de Fluorescência para Anticorpo , Reação em Cadeia da Polimerase , Prevalência , População RuralRESUMO
Abstract INTRODUCTION: Chagas disease is caused by the protozoa Trypanosoma cruzi. Its main reservoir is the domestic dog, especially in rural areas with favorable characteristics for vector establishment and proliferation. The aims of this study were to collect data, survey and map the fauna, and identify T. cruzi infection in triatomines, as well as to assess the presence of anti-T. cruzi antibodies in dogs in rural areas of the municipality of Mossoró, Brazil. METHODS: An active entomologic research was conducted to identify adult specimens through an external morphology dichotomous key. The analysis of natural infection by T. cruzi in the insects was performed by isolation in culture and polymerase chain reaction. The antibody testing for T. cruzi in dogs was performed by enzyme-linked immunosorbent assay and indirect immunofluorescence assay. RESULTS: A total of 68 triatomines were captured, predominantly the Triatoma brasiliensis brasiliensis (Neiva 1911) species. The vector mapping displayed areas with greater risk for parasite transmission. Of the examined triatomines (51 specimens), 41.2% (21/51) were positive on polymerase chain reaction, and all were negative on culture. In the serum testing, 11% (25/218) of dogs were seropositive, but no association was found between the serologic results and the presence and infection by T. cruzi in triatomines. CONCLUSIONS: This study demonstrated the movement of T. cruzi in the studied area, by the presence of vectors and naturally infected domestic reservoirs. The mapping of the studied rural area demonstrates the risk of disease transmission.
Assuntos
Animais , Cães , Trypanosoma cruzi/imunologia , Anticorpos Antiprotozoários/sangue , Triatominae/parasitologia , Doença de Chagas/veterinária , Doenças do Cão/diagnóstico , Insetos Vetores/parasitologia , População Rural , Brasil/epidemiologia , Reação em Cadeia da Polimerase , Prevalência , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Técnica Indireta de Fluorescência para Anticorpo , Doenças do Cão/epidemiologiaRESUMO
This survey aimed to assess the presence of triatomine vectors of Chagas disease within the rural communities of São João do Piauí, Northeast Brazil. Intradomiciliary and peridomiciliary collection strategies were implemented wherein 279 specimens of Triatoma brasiliensis macromelasoma, both nymph and adult were found in 15 (50%) of the studied homes. Of the intradomiciliary insects, 73 (67.6%) were identified as nymph instars (1st instar [N1]= 6, N2= 14, N3= 28, N4= 7 and N5= 18). In the studied communities, a continuous interaction between triatomine bugs and humans could be shown. It is therefore urgent that suitable strategies for the control of the triatomine vector are implemented in this area.
Assuntos
Habitação , Insetos Vetores/anatomia & histologia , Triatoma/anatomia & histologia , Animais , Brasil , Doença de Chagas/transmissão , Insetos Vetores/classificação , População Rural , Triatoma/classificaçãoRESUMO
Triatoma sherlocki Papa, Jurberg, Carcavallo, Cerqueira & Barata was described in 2002, based on specimens caught in the wild in the municipality of Gentio do Ouro, Bahia, Brazil. In 2009, nymphs and adults were detected inside homes and sylvatic specimens were positive for Trypanosoma cruzi (Chagas). No information on the bionomics of T. sherlocki exists, although such data are considered essential to estimate its vector and colonization potential in domestic environments. Herein, the biological cycle of T. sherlocki was studied based on 123 eggs, with nymphs and adults fed on Mus musculus (Linnaeus). Nymphal development time phases, number of meals consumed, and stage-specific mortality rates were analyzed. Survival time under starvation conditions was measured between ecdysis and death among 50 nymphs (first to fifth instar) and 50 male and female adults. The median development time from egg to adult was 621.0 (CI: 489-656) d. The number of meals consumed ranged from 1 to 20 for nymphs of the first to fifth instar. The fifth instar showed the greatest resistance to starvation, with a mean of 156.5 d. The high number of meals consumed by T. sherlocki favored infection with and transmission of T. cruzi. The full development of this species under laboratory conditions with a low mortality rate indicates that this vector presents biological characteristics that may contribute to its adaptation to artificial human ecotopes. Its high resistance to starvation emphasizes the importance of entomological surveillance for this species.
Assuntos
Estágios do Ciclo de Vida , Características de História de Vida , Triatoma/fisiologia , Animais , Brasil , Comportamento Alimentar , Feminino , Privação de Alimentos , Masculino , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Óvulo/crescimento & desenvolvimento , Óvulo/fisiologia , Triatoma/crescimento & desenvolvimentoRESUMO
ABSTRACT This survey aimed to assess the presence of triatomine vectors of Chagas disease within the rural communities of São João do Piauí, Northeast Brazil. Intradomiciliary and peridomiciliary collection strategies were implemented wherein 279 specimens of Triatoma brasiliensis macromelasoma, both nymph and adult were found in 15 (50%) of the studied homes. Of the intradomiciliary insects, 73 (67.6%) were identified as nymph instars (1st instar [N1]= 6, N2= 14, N3= 28, N4= 7 and N5= 18). In the studied communities, a continuous interaction between triatomine bugs and humans could be shown. It is therefore urgent that suitable strategies for the control of the triatomine vector are implemented in this area.
Assuntos
Animais , Habitação , Triatoma/anatomia & histologia , Brasil , Doença de Chagas/transmissão , Insetos Vetores/anatomia & histologia , Insetos Vetores/classificação , População Rural , Triatoma/classificaçãoRESUMO
During a medical entomology course in Boa Vista, Roraima, colonies of Triatoma maculata closely associated with pigeon nests were observed in concrete air-conditioner box located on the external plastered and cemented walls of a modern brick-built apartment block. In only one eight-hole ceramic brick, located inside one air-conditioner box, 127 specimens of T. maculata were collected. T. maculata is a recognised vector of Trypanosoma cruzi in the surrounding area and its domiciliation increases the risk of Chagas disease transmission.
Assuntos
Doença de Chagas/transmissão , Insetos Vetores/fisiologia , Triatoma/parasitologia , Trypanosoma cruzi/fisiologia , Distribuição Animal , Animais , Doenças das Aves/imunologia , Brasil , Columbidae/parasitologia , Habitação , Humanos , População UrbanaRESUMO
We conducted a lab-based comparative study on vector capacity features of two species of triatomines: Triatoma brasiliensis and T. melanica. Both are members of the T. brasiliensis species complex. The former is the most important Chagas disease vector in the northeastern region of Brazil. To date, no transmission via T. melanica has been recorded. Immature insects exhibited distinct intermoult periods without a direct relationship to a given species. Females of T. brasiliensis consumed an average of 1.9 times more meals (mean = 12.92 vs 6.63) and survived for a shorter period (mean =330.8 days) than T. melanica (mean = 365.2 days), probably due to the cost of reproduction (all significant at P<0.05). These data support the idea that T. brasiliensis is more adapted to lab conditions and is more able to infest domiciles than T. melanica. We also found significant distinctions in other features between these species, such as the elapsed time without eating before molting, which was higher for the second, third, and fifth nymph stages of T. melanica. Regarding features analyzed related to vector capacity, insects of all life stages of both species were considered competent to transmit Trypanosoma cruzi because they needed many feedings (mean =1.5-3.82) to moult and because a high proportion (>39%) of insects defecated rapidly (<30 s) after feeding. Overall, results highlight the need to extend vector surveillance to T. melanica.
Assuntos
Insetos Vetores/parasitologia , Triatoma/parasitologia , Trypanosoma cruzi/isolamento & purificação , Animais , Brasil , Doença de Chagas , Ecossistema , Comportamento Alimentar , Feminino , Insetos Vetores/classificação , Triatoma/classificaçãoRESUMO
BACKGROUND: Panstrongylus lutzi (Neiva & Pinto, 1923) is a triatomine species native to Caatinga habitats in north-eastern Brazil. It is considered an important vector of Chagas disease in this region, presenting high rates of natural infection with Trypanosoma cruzi Chagas, 1909, and readily invading houses by flight. This study describes a previously unknown chromosomal sex system in the genus Panstrongylus based on P. lutzi. METHODS: Fifth-instar and male adults of P. lutzi originating from municipality of Várzea Alegre, Ceará (Brazil) were analysed. Chromosomal analyses of male meiotic process were done by Giemsa staining. RESULTS: Chromosomal analyses of male meiosis reveal a diploid chromosome number of 24 chromosomes (20 autosomes plus X1X2X3Y). During meiotic prophase I, the sex chromosomes remained close together, forming four heteropycnotic chromocenters in zygotene, and a single chromocenter in pachytene and diplotene. Still at the diplotene stage, each one of the ten autosomal bivalents showed an evident chiasma. In metaphase I, the four sex chromosomes appeared clearly separated. The three X chromosomes were the smallest of the complement and isopycnotic with respect to the Y chromosome. Two bivalents appear larger, whereas the other eight showed no significant difference in size. CONCLUSION: Karyotype analysis of P. lutzi revealed a new sex system in the genus Panstrongylus. This result is of utmost importance to karyosystematics of P. lutzi, and demonstrates the need for further studies of this type in the subfamily Triatominae.
Assuntos
Cromossomos de Insetos , Panstrongylus/genética , Processos de Determinação Sexual/genética , Animais , Brasil , Cariotipagem , Masculino , Cromossomos SexuaisRESUMO
Bed bugs are hematophagous insects which due to their morphological and biological characteristics are able to easily adapt themselves to human households. The authors describe two cases of dermatitis caused by bed bug bites in the city of Rio de Janeiro, Brazil. Patients presented linear lesions in the usual "breakfast, lunch and dinner" arrangement, suggesting this diagnosis. A visit to their dwellings showed infestation of insects identified as Cimex hemipterus. The knowledge of these insects by the dermatological community will contribute to an accurate diagnosis as well as subsidize the dissemination of information aiming for prevention.