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1.
Rev Soc Bras Med Trop ; 53: e20190503, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267457

RESUMO

INTRODUCTION: The genus Rhodnius in the subfamily Triatominae comprises 20 species, which can transmit Trypanosoma cruzi and Trypanosoma rangeli. Due to the development of molecular techniques, Triatominae species can now be characterized by mitochondrial and nuclear markers, making it possible to verify and/or correct the existing data on these species. The results achieved in this study provide a more detailed and accurate differentiation of the Rhodnius species, helping the establishment of a more appropriate classification. METHODS: Data collection was performed by DNA analysis, morphological and morphometric studies to distinguish four populations of R. neglectus and four of R. prolixus. Phylogenetic data were compared to morphological and morphometric data. RESULTS: The analysis of Cytb fragments suggests that the four colonies designated to Rhodnius neglectus as well as those of R. prolixus were correctly identified. CONCLUSIONS: The morphological characters observed in the specimens of the colonies originally identified as R. prolixus and R. neglectus, such as the presence or absence of collar in the eggs, the patterns of the median process of the pygophore, and anterolateral angle, are consistent with the species. Geometric morphometrics also show an intraspecific variability in R. prolixus.


Assuntos
Insetos Vetores/anatomia & histologia , Rhodnius/classificação , Animais , Doença de Chagas/transmissão , Insetos Vetores/classificação , Insetos Vetores/genética , Masculino , Filogenia , Rhodnius/anatomia & histologia , Rhodnius/genética , Análise de Sequência de DNA , Especificidade da Espécie
2.
Rev Soc Bras Med Trop ; 53: e20190560, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348431

RESUMO

INTRODUCTION: Congenital transmission (CT) of Trypanosoma cruzi has led to globalization of Chagas disease and its growing relevance as a public health problem. Although the occurrence of CT has been associated with several factors, its mechanisms are still unknown. This study aimed to analyze the geographical and familiar variables of mothers and their association with CT of Chagas disease in a population living in non-endemic areas of Argentina for the last decades. METHODS: We developed a retrospective cohort study in a sample of 2120 mother-child pairs who attended three reference centers in the cities of Buenos Aires, Santa Fe, and Salta between 2002 and 2015. RESULTS: The highest CT rates were observed in children born to Argentinean mothers (10.7%) and in children born to mothers from Buenos Aires (11.7%). Considering the areas of origin of the mothers, those from areas of null-low risk for vector-borne infection had higher CT rates than those from areas of medium-high risk (11.1% vs 8.2%). We also observed a significant intra-familiar "cluster effect," with CT rates of 35.9% in children with an infected sibling, compared to 8.2% in children without infected siblings (RR=4.4 95% CI 2.3-8.4). CONCLUSIONS: The associations observed suggest a higher CT rate in children born to mothers who acquired the infection congenitally, with familiar antecedents, and from areas without the presence of vectors. These observations are considered new epidemiological evidence about Chagas disease in a contemporary urban population, which may contribute to the study of CT and may also be an interesting finding for healthcare professionals.


Assuntos
Doença de Chagas/epidemiologia , Doença de Chagas/transmissão , Transmissão Vertical de Doença Infecciosa/estatística & dados numéricos , Complicações Parasitárias na Gravidez/epidemiologia , Adolescente , Adulto , Animais , Argentina/epidemiologia , Feminino , Humanos , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Gravidez , Estudos Retrospectivos , Fatores de Risco , População Urbana , Adulto Jovem
3.
PLoS Negl Trop Dis ; 14(3): e0007910, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32150562

RESUMO

Anthropogenic environmental alterations such as urbanization can threaten native populations as well as create novel environments that allow human pests and pathogens to thrive. As the number and size of urban environments increase globally, it is more important than ever to understand the dispersal dynamics of hosts, vectors and pathogens of zoonotic disease systems. For example, a protozoan parasite and the causative agent of Chagas disease in humans, Trypanosoma cruzi, recently colonized and spread through the city of Arequipa, Peru. We used population genomic and phylogenomic tools to analyze whole genomes of 123 T. cruzi isolates derived from vectors and non-human mammals throughout Arequipa to determine patterns of T. cruzi dispersal. The data show significant population genetic structure within city blocks-parasites in the same block tend to be very closely related-but no population structure among blocks within districts-parasites in neighboring blocks are no more closely related to one another than to parasites in distant districts. These data suggest that T. cruzi dispersal within a block occurs regularly and that occasional long-range dispersal events allow the establishment of new T. cruzi populations in distant blocks. Movement of domestic animals may be the primary mechanism of inter-block and inter-district T. cruzi dispersal.


Assuntos
Animais Domésticos/parasitologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Transmissão de Doença Infecciosa , Genótipo , Filogenia , Trypanosoma cruzi/isolamento & purificação , Animais , Doença de Chagas/transmissão , Vetores de Doenças , Humanos , Epidemiologia Molecular , Peru/epidemiologia , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética
4.
Rev Soc Bras Med Trop ; 53: e20190436, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32187341

RESUMO

INTRODUCTION: Triatomines are hematophagous insects of epidemiological importance because they are vectors of Chagas disease. We present here the first report of Rhodnius montenegrensis in Amazonas, Brazil. METHODS: Triatomines were collected from Attalea butyracea palm trees in the municipality of Guajará. RESULTS: Two adult female R. montenegrensis specimens were identified. CONCLUSIONS: The present study confirms that the number of triatomine species within the Amazon has increased from 10 to 11, and the number of Brazilian states with R. montenegrensis has increased from two to three.


Assuntos
Insetos Vetores/anatomia & histologia , Insetos Vetores/classificação , Rhodnius/anatomia & histologia , Rhodnius/classificação , Animais , Brasil , Doença de Chagas/transmissão , Feminino
5.
Mem Inst Oswaldo Cruz ; 115: e190364, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32130371

RESUMO

Oral transmission of Chagas disease has been increasing in Latin American countries. The present study aimed to investigate changes in hepatic function, coagulation factor levels and parasite load in human acute Chagas disease (ACD) secondary to oral Trypanosoma cruzi transmission. Clinical and epidemiological findings of 102 infected individuals attended in the State of Pará from October 2013 to February 2016 were included. The most common symptoms were fever (98%), asthenia (83.3%), face and limb edema (80.4%), headache (74.5%) and myalgia (72.5%). The hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of 30 ACD patients were higher compared with controls, and this increase was independent of the treatment with benznidazole. Moreover, ACD individuals had higher plasma levels of activated protein C and lower levels of factor VII of the coagulation cascade. Patients with the highest parasite load had also the most increased transaminase levels. Also, ALT and AST were associated moderately (r = 0.429) and strongly (r = 0.595) with parasite load respectively. In conclusion, the present study raises the possibility that a disturbance in coagulation and hepatic function may be linked to human ACD.


Assuntos
Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Doença de Chagas/fisiopatologia , Fator VIIa/análise , Fígado/fisiopatologia , Proteína C/análise , Doença Aguda , Adulto , Biomarcadores/sangue , Brasil/epidemiologia , Estudos de Casos e Controles , Doença de Chagas/sangue , Doença de Chagas/enzimologia , Doença de Chagas/transmissão , Feminino , Humanos , Fígado/enzimologia , Masculino , Pessoa de Meia-Idade , Carga Parasitária , Estudos Prospectivos
6.
MMWR Morb Mortal Wkly Rep ; 69(7): 193-195, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32078594

RESUMO

On December 13, 2017, the Missouri Department of Health and Senior Services (MDHSS) was notified of a suspected case of Chagas disease in a Missouri woman. The patient had donated blood, and laboratory screening revealed antibodies to Trypanosoma cruzi, the parasite that causes Chagas disease. Evaluation by physicians found no clinical symptoms consistent with Chagas disease. The patient had no travel history that would have suggested a significant risk for Chagas disease risk and had no occupational exposure to the disease agent. She had never received a blood transfusion or organ transplant. Confirmatory testing of the patient's serum at CDC for T. cruzi antibody was consistent with infection. These findings raise the possibility that the exposure to T. cruzi occurred locally (autochthonously) in Missouri. Although the insect vector for the parasite T. cruzi, triatomines (commonly known as "kissing bugs"), has been identified previously in Missouri, no locally acquired human cases of Chagas disease have been identified in the state. Health care providers and public health professionals should be aware of the possibility of locally acquired Chagas disease in the southern United States.


Assuntos
Doença de Chagas/diagnóstico , Anticorpos Antiprotozoários/isolamento & purificação , Doadores de Sangue , Doença de Chagas/transmissão , Feminino , Humanos , Pessoa de Meia-Idade , Missouri , Trypanosoma cruzi/imunologia
7.
Rev Soc Bras Med Trop ; 53: e20190299, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31994663

RESUMO

INTRODUCTION: Triatomine bugs are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. METHODS: Triatomine bugs were collected and identified following established protocols. In addition, infection with T. cruzi was detected by microscopic and molecular analysis. RESULTS: We captured an adult male specimen of the Eratyrus cuspidatus species that has not been reported in the state of Campeche. CONCLUSIONS: This finding provides new information on the distribution of E. cuspidatus in Mexico. However, more studies are needed to determine their epidemiological significance.


Assuntos
Insetos Vetores/anatomia & histologia , Insetos Vetores/classificação , Triatominae/anatomia & histologia , Triatominae/classificação , Animais , Doença de Chagas/transmissão , Masculino , México
8.
Bull Entomol Res ; 110(1): 169-176, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31337451

RESUMO

Transmission of Trypanosma cruzi (Kinetoplastida: Trypanosomatidae) occurs when feces/urine of infected triatomines come into contact with mucous membranes or damaged skin, and this occurs mainly when insects defecate while feeding on the host. Thus, the vector competence of the triatomines is associated with their feeding and excretion/defecation behavior. This work studied for the first time the effect of T. cruzi infection on feeding and excretion/defecation patterns of Triatoma infestans (Hemiptera: Reduviidae). Uninfected and infected fifth-instar nymphs were fed ad libitum and their feeding behavior and defecations were registered during and after feeding. The feeding pattern did not show differences between the experimental groups. However, the infected nymphs began to defecate earlier, defecated in greater quantity and there was a greater proportion of defecating individuals compared to uninfected nymphs. These results show that T. cruzi affected the excretion/defecation pattern of T. infestans in a way that would increase the probability of contact between infective feces and the mammalian host.


Assuntos
Interações Hospedeiro-Parasita , Triatoma/parasitologia , Trypanosoma cruzi/fisiologia , Animais , Doença de Chagas/transmissão , Defecação , Comportamento Alimentar , Triatoma/fisiologia
9.
Acta Trop ; 201: 105188, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31545949

RESUMO

Triatoma petrocchiae is the newly member of the Triatoma brasiliensis species complex. This species overlaps with T. brasiliensis in geographic and ecotypic occupation in the sylvatic habitat because both inhabit rocky outcrops in the semi-arid portion of Brazilian northeast. In this region T. brasiliensis is the most important Chagas disease vector because it constantly colonizes domiciles. In contrast, T. petrocchiae is rarely found in peri or intradomiciliary habitats - reason why little is known about this species. Therefore, Here, we present information for the first time on. the T. petrocchiae ecotopes, genetic diversity, Trypanosoma cruzi prevalence/genotyping in comparison to T. brasiliensis. We found T. brasilensis (N = 223) and T. petrocchiae (N = 69) in co-habitation in rocky outcrops in three Districts of Paraíba and Rio Grande do Norte states. Forty-tree T. petrocchiae insects of eleven sampling spots (composing three geographic populations) were genotyped for the mitochondrial Cyt B gene and little geographic structure was observed. Tajima's D test suggested that species is evolving toward a mutation-drift equilibrium in our collection range. Sylvatic T. petrocchiae had 4% (3/68) of infected insects by T. cruzi, whereas T. brasiliensis had 26% (59/223). Fluorescent Fragment Length Barcoding demonstrated that all three T. petrocchiae harbored TcI whereas T. brasiliensis had TcI, but also TcIII, TcII/TcVI and T. rangeli genotype A, sometimes under mixed infections. None of infected T. petrocchiae were carrying mixed infections. However, this result should be confirmed using a larger pool of infected bugs. We here presented the first documentation of T. rangeli infecting T. brasiliensis. The finding of infected T. petrocchiae calls for constant vector monitoring because the epidemiologic scenario is dynamic and sylvatic vectors are progressively found in adaptation to anthropic environments.


Assuntos
Doença de Chagas/transmissão , Insetos Vetores/parasitologia , Simpatria , Triatoma/parasitologia , Trypanosoma cruzi/genética , Animais , Brasil/epidemiologia , Doença de Chagas/epidemiologia , Ecossistema , Variação Genética , Genótipo , Epidemiologia Molecular , Prevalência
10.
PLoS Negl Trop Dis ; 13(12): e0007902, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31834879

RESUMO

Trypanosoma cruzi is the causative agent of Chagas disease, a Neglected Tropical Disease affecting 8 million people in the Americas. Triatomine hematophagous vectors feed on a high diversity of vertebrate species that can be reservoirs or dead-end hosts, such as avian species refractory to T. cruzi. To understand its transmission dynamics in synanthropic and domesticated species living within villages is essential to quantify disease risk and assess the potential of zooprophylaxis. We developed a SI model of T. cruzi transmission in a multi-host community where vector reproduction and parasite transmission depend on a triatomine blood-feeding rate accounting for vector host preferences and interference while feeding. The model was parameterized to describe T. cruzi transmission in villages of the Yucatan peninsula, Mexico, using the information about Triatoma dimidiata vectors and host populations accumulated over the past 15 years. Extensive analyses of the model showed that dogs are key reservoirs and contributors to human infection, as compared to synanthropic rodents and cats, while chickens or other domesticated avian hosts dilute T. cruzi transmission despite increasing vector abundance. In this context, reducing the number of dogs or increasing avian hosts abundance decreases incidence in humans by up to 56% and 39%, respectively, while combining such changes reduces incidence by 71%. Although such effects are only reached over >10-years periods, they represent important considerations to be included in the design of cost-effective Integrated Vector Management. The concomitant reduction in T. cruzi vector prevalence estimated by simulating these zooprophylactic interventions could indeed complement the removal of colonies from the peridomiciles or the use of insect screens that lower vector indoor abundance by ~60% and ~80%. These new findings reinforce the idea that education and community empowerment to reduce basic risk factors is a cornerstone to reach and sustain the key objective of interrupting Chagas disease intra-domiciliary transmission.


Assuntos
Animais Domésticos/parasitologia , Animais Selvagens/parasitologia , Doença de Chagas/transmissão , Reservatórios de Doenças/parasitologia , Transmissão de Doença Infecciosa , Insetos Vetores/crescimento & desenvolvimento , Triatoma/crescimento & desenvolvimento , Animais , Doença de Chagas/veterinária , Simulação por Computador , Humanos , Incidência , México
11.
Rev Med Chil ; 147(6): 683-692, 2019 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-31859820

RESUMO

BACKGROUND: Reproductive number (R0)-maps estimate risk zones of vector-borne diseases and geographical distribution changes under climate change. AIM: To map R0 aiming to estimate the epidemiological risk of Chagas disease in Chile, its distribution and possible changes due to the global climate change. MATERIAL AND METHODS: We used a relationship between R0 and entomological parameters of vectors as function of environmental variables, to map the risk of Chagas disease in Chile, under current and projected future environmental conditions. RESULTS: We obtained a geographical R0 estimation of Chagas disease in Chile. The highest R0averages correspond to the Central-Northern regions of Chile. T. cruzi transmission area could increase in the future due to climate changes. Independent of the future condition, both for optimistic and pessimistic climate change scenarios, the area of potential risk for Chagas disease transmission would increase. The estimated R0 values suggest that, if a control of T. infestans is not maintained, Chagas disease endemic status will persist or increase, independently of the climate change scenarios. CONCLUSIONS: Mapping R0 values is an effective method to assess the risk of Chagas disease. The eventual increase in the transmission area of the disease is worrisome.


Assuntos
Doença de Chagas/epidemiologia , Mudança Climática/estatística & dados numéricos , Vetores de Doenças , Medição de Risco/métodos , Animais , Dióxido de Carbono , Doença de Chagas/transmissão , Chile/epidemiologia , Feminino , Geografia , Humanos , Masculino , Fatores de Risco , Estatísticas não Paramétricas , Temperatura , Triatoma , Trypanosoma cruzi
12.
PLoS Negl Trop Dis ; 13(12): e0007430, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31841558

RESUMO

The transmission of Trypanosoma cruzi to humans is determined by multiple ecological, socio-economic and cultural factors acting at different scales. Their effects on human infection with T. cruzi have often been examined separately or using a limited set of ecological and socio-demographic variables. Herein, we integrated the ecological and social dimensions of human infection risk with the spatial distribution patterns of human and vector (Triatoma infestans) infection in rural communities of the Argentine Chaco composed of indigenous people (90% Qom) and a creole minority. We conducted serosurveys in 470 households aiming at complete population enumeration over 2012-2015. The estimated seroprevalence of T. cruzi prior to the implementation of an insecticide spraying campaign (2008) was 29.0% (N = 1,373 in 301 households), and was twice as large in Qom than creoles. Using generalized linear mixed models, human seropositive cases significantly increased with infected triatomine abundance, having a seropositive household co-inhabitant and household social vulnerability (a multidimensional index of poverty), and significantly decreased with increasing host availability in sleeping quarters (an index summarizing the number of domestic hosts for T. infestans). Vulnerable household residents were exposed to a higher risk of infection even at low infected-vector abundances. The risk of being seropositive increased significantly with house infestation among children from stable households, whereas both variables were not significantly associated among children from households exhibiting high mobility within the communities, possibly owing to less consistent exposures. Human infection was clustered by household and at a larger spatial scale, with hotspots of human and vector infection matching areas of higher social vulnerability. These results were integrated in a risk map that shows high-priority areas for targeted interventions oriented to suppress house (re)infestations, detect and treat infected children, and thus reduce the burden of future disease.


Assuntos
Doença de Chagas/epidemiologia , Doença de Chagas/transmissão , Transmissão de Doença Infecciosa , Relações Interpessoais , População Rural , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Argentina/epidemiologia , Criança , Pré-Escolar , Economia , Grupos Étnicos , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Topografia Médica , Triatominae/crescimento & desenvolvimento , Adulto Jovem
13.
Rev Soc Bras Med Trop ; 53: e20190119, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31859942

RESUMO

INTRODUCTION: Oral transmission of acute Chagas disease is an emerging public health concern. This study aimed to detect insect fragments in experimentally contaminated food, by comparing triatomines with other insects. METHODS: Food samples were experimentally contaminated with insects, processed to recover their fragments by light filth, and analyzed by microscopy and Polymerase Chain Reaction (PCR). RESULTS: Morphological differences between coleopteran and triatomine insects were observed in microscopic images. PCR was efficient in amplifying Triatominae DNA in the experimentally contaminated food. CONCLUSIONS: This methodology could be utilized by food analysts to identify possible insect contamination in food samples.


Assuntos
Besouros/classificação , Parasitologia de Alimentos , Sucos de Frutas e Vegetais/parasitologia , Insetos Vetores/classificação , Saccharum/parasitologia , Triatominae/classificação , Animais , Doença de Chagas/transmissão , Humanos , Reação em Cadeia da Polimerase
14.
Rev Soc Bras Med Trop ; 52: e20190020, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31778398

RESUMO

INTRODUCTION: Different blood meal sources can affect biology of triatomines. METHODS: We studied the influence of two different blood meal sources (rabbits and hens) on five biological parameters in Meccus phyllosomus pallidipennis and collected biological parameters. RESULTS: The cohort fed on rabbits had a shorter median life-cycle and lower mortality rate than that fed on hens. Both cohorts required a similar number of blood meals to reach adulthood. Median longevity and number of blood meals for adults were similar between both cohorts. CONCLUSIONS: The studied parameters reflect the high grade of adaptation of M. p. pallidipennis feeding on different hosts.


Assuntos
Comportamento Alimentar/fisiologia , Insetos Vetores/fisiologia , Estágios do Ciclo de Vida/fisiologia , Triatominae/fisiologia , Animais , Doença de Chagas/transmissão , Galinhas , Coelhos
15.
Rev Soc Bras Med Trop ; 52: e20190278, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31778421

RESUMO

INTRODUCTION: Trypanosoma cruzi is the etiological agent of Chagas disease (CD), a zoonotic infection transmitted by triatomine bug vectors to human beings. Although the story of this parasitic infection was born in Brazil and here this has made major step forward information, the same cannot be said about the actual distribution of the triatomine vector in several areas of this country. The aim of this study was to assess the occurrence of triatomine species in an endemic region for CD in Northeastern Brazil. METHODS: A retrospective study was performed using data obtained from 2008 to 2017. All information was provided by the V Gerência Regional de Saúde of the state of Pernambuco. The spatial distribution of triatomine species was analyzed by drawing a map using the Quantum geographic information system. RESULTS: A total of 4,694 triatomine specimens (469.4 ± 221.2 per year) were collected during the period 2008-2017, with 94.5% (4,434/4,694) at the intradomicile and 5.5% (260/4,694) at peridomicile environment. Of all arthropods collected, 92.5% (4,340/4,694) and 7.5% (354/4,694) were adults and nymphs, respectively. The species most frequently detected were Panstrongylus lutzi (30.36%), Triatoma brasiliensis (26.12%), Triatoma pseudomaculata (22.43%), and Panstrongylus megistus (20.54%). CONCLUSIONS: These data contribute to a better understanding of the distribution of T. cruzi infection in the Northeastern region of Brazil. Preventive measures based on vector control should be implemented in the study area in order to reduce the burden this neglected tropical disease.


Assuntos
Distribuição Animal , Insetos Vetores/classificação , Triatominae/classificação , Animais , Brasil , Doença de Chagas/transmissão , Doenças Endêmicas , Densidade Demográfica , Estudos Retrospectivos
16.
Parasit Vectors ; 12(1): 478, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31610815

RESUMO

BACKGROUND: Mepraia gajardoi and Mepraia spinolai are endemic triatomine vector species of Trypanosoma cruzi, a parasite that causes Chagas disease. These vectors inhabit arid, semiarid and Mediterranean areas of Chile. Mepraia gajardoi occurs from 18° to 25°S, and M. spinolai from 26° to 34°S. Even though both species are involved in T. cruzi transmission in the Pacific side of the Southern Cone of South America, no study has modelled their distributions at a regional scale. Therefore, the aim of this study is to estimate the potential geographical distribution of M. spinolai and M. gajardoi under current and future climate scenarios. METHODS: We used the Maxent algorithm to model the ecological niche of M. spinolai and M. gajardoi, estimating their potential distributions from current climate information and projecting their distributions to future climatic conditions under representative concentration pathways (RCP) 2.6, 4.5, 6.0 and 8.5 scenarios. Future predictions of suitability were constructed considering both higher and lower public health risk situations. RESULTS: The current potential distributions of both species were broader than their known ranges. For both species, climate change projections for 2070 in RCP 2.6, 4.5, 6.0 and 8.5 scenarios showed different results depending on the methodology used. The higher risk situation showed new suitable areas, but the lower risk situation modelled a net reduction in the future potential distribution areas of M. spinolai and M. gajardoi. CONCLUSIONS: The suitable areas for both species may be greater than currently known, generating new challenges in terms of vector control and prevention. Under future climate conditions, these species could modify their potential geographical range. Preventive measures to avoid accidental human vectorial transmission by wild vectors of T. cruzi become critical considering the uncertainty of future suitable areas projected in this study.


Assuntos
Doença de Chagas/transmissão , Mudança Climática , Insetos Vetores/fisiologia , Triatominae/fisiologia , Trypanosoma cruzi/fisiologia , Animais , Área Sob a Curva , Doença de Chagas/epidemiologia , Chile/epidemiologia , Humanos , Umidade , Insetos Vetores/parasitologia , Modelos Biológicos , Filogeografia , Curva ROC , Chuva , Medição de Risco , Temperatura , Triatominae/parasitologia
17.
PLoS Negl Trop Dis ; 13(10): e0007766, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31600199

RESUMO

BACKGROUND: Triatoma brasiliensis, a triatomine-bug vector of Chagas disease, evolved in the semiarid Caatinga, where it occupies rocky outcrops, shrubby cacti, and human dwellings. Dwellings and rocks are considered high-quality microhabitats for this saxicolous species, whereas cacti probably represent secondary, lower-quality microhabitats. This 'microhabitat-quality hierarchy' hypothesis predicts that T. brasiliensis populations occupying dwellings or rocks should endure harsh environmental conditions better than their cactus-living relatives. METHODS/FINDINGS: We tested this prediction by comparing T. brasiliensis infestation (proportion of microhabitats with bugs), density (bugs per microhabitat), and crowding (bugs per infested microhabitat) in dwellings, rocks, and cacti sampled before and during the extreme drought that ravaged the Caatinga in 2012-2016. We used random-intercepts generalized linear mixed models to account for microhabitat spatial clustering and for variations in bug-catch effort; we assessed model performance and computed model-averaged effect estimates using Akaike's information criterion. Pre-drought infestation was similar across microhabitat types; during the drought, infestation remained stable in dwellings and rocks but dropped in cacti. Pre-drought bug density declined from dwellings to rocks to cacti; an additional decline associated with the drought was largely comparable across microhabitats, albeit perhaps somewhat larger in cacti. Finally, pre-drought bug crowding was higher in dwellings than in rocks or cacti and changed little during the drought-possibly with a downward trend in dwellings and an upward trend in cacti. CONCLUSIONS: Triatoma brasiliensis populations fared better in dwellings and rocks than in cacti during extreme drought. Estimates of microhabitat and drought effects on infestation, density, and crowding suggest that only a few cacti (versus many rocks and dwellings) represent good-quality habitat under such extremely harsh conditions. Our findings provide empirical support to the microhabitat-quality hierarchy hypothesis, and imply that T. brasiliensis can endure extreme climate by exploiting high-quality microhabitats, whether wild or man-made, in the semiarid Caatinga.


Assuntos
Clima , Secas , Triatoma , Animais , Brasil , Doença de Chagas/transmissão , Ecossistema , Humanos , Insetos Vetores
18.
Parasit Vectors ; 12(1): 504, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31665056

RESUMO

BACKGROUND: Triatomine bugs are vectors of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. Rhodnius pallescens is a major vector of Chagas disease in Panama. Understanding the microbial ecology of disease vectors is important in the development of vector management strategies that target vector survival and fitness. In this study we examined the whole-body microbial composition of R. pallescens from three locations in Panama. METHODS: We collected 89 R. pallescens specimens using Noireau traps in Attalea butyracea palms. We then extracted total DNA from whole-bodies of specimens and amplified bacterial microbiota using 16S rRNA metabarcoding PCR. The 16S libraries were sequenced on an Illumina MiSeq and analyzed using QIIME2 software. RESULTS: We found Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes to be the most abundant bacterial phyla across all samples. Geographical location showed the largest difference in microbial composition with northern Veraguas Province having the most diversity and Panama Oeste Province localities being most similar to each other. Wolbachia was detected in high abundance (48-72%) at Panama Oeste area localities with a complete absence of detection in Veraguas Province. No significant differences in microbial composition were detected between triatomine age class, primary blood meal source, or T. cruzi infection status. CONCLUSIONS: We found biogeographical regions differ in microbial composition among R. pallescens populations in Panama. While overall the microbiota has bacterial taxa consistent with previous studies in triatomine microbial ecology, locality differences are an important observation for future studies. Geographical heterogeneity in microbiomes of vectors is an important consideration for future developments that leverage microbiomes for disease control.


Assuntos
Bactérias/classificação , Doença de Chagas/transmissão , Insetos Vetores/microbiologia , Microbiota , Rhodnius/microbiologia , Actinobacteria/classificação , Actinobacteria/genética , Análise de Variância , Animais , Bactérias/genética , Bacteroidetes/classificação , Bacteroidetes/genética , Biodiversidade , Código de Barras de DNA Taxonômico , Ecossistema , Firmicutes/classificação , Firmicutes/genética , Biblioteca Gênica , Humanos , Insetos Vetores/fisiologia , Panamá , Filogeografia , Reação em Cadeia da Polimerase , Proteobactérias/classificação , Proteobactérias/genética , RNA Ribossômico 16S/química , Rhodnius/fisiologia
19.
Rev Inst Med Trop Sao Paulo ; 61: e47, 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31531625

RESUMO

Triatomines are vectors of Trypanosoma cruzi , the etiological agent of Chagas disease, which affects between 6 and 12 million people in Latin America, with an incidence rate of 12 thousand cases per year. In the Ceara State, the predominance of the caatinga biome, coupled with a large rural area with precarious human habitations, provides several s shelters for these insects. In this study, we determined the spatiotemporal distribution of triatomine dispersion rates in the Cariri region, Southern Ceara and ascertained the possible association between these rates with socioeconomic and environmental factors. Dispersion rates (number of positive localities/number of searched localities × 100) were analyzed regarding 13 municipalities from the Ceara State, from 2009 to 2013. Socioeconomic and environmental variables collected from national research institutes were associated with the dispersion rates and their local empirical Bayesian estimates. All the municipalities recorded dispersion rates over 10% in all years, and 11 municipalities had average rates over 40% for the period of study. Significant differences were observed among the municipality means. The highest rates were observed in Antonina do Norte and Potengi. According to the correlation analysis, the proportion between the occupied population and the total population showed a significant negative correlation, as well as the percentage of the population who lives under adequate sanitary conditions. Both, the percentage of revenues from external sources and the percentage of urban households in reforested blocks had a significant positive correlation. Our results show that socioeconomic and environmental variables can be factors that contribute to both, the maintenance and the reduction of the elevated dispersion rates observed in the study area. Similar researches that encompass more municipalities from that region may reinforce Chagas disease surveillance and control in the Northeast of Brazil.


Assuntos
Habitação , Insetos Vetores/classificação , Triatominae/classificação , Animais , Teorema de Bayes , Brasil , Doença de Chagas/transmissão , Meio Ambiente , Humanos , Densidade Demográfica , Dinâmica Populacional , Fatores Socioeconômicos
20.
Acta Trop ; 200: 105177, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31539526

RESUMO

The parasite manipulation hypothesis states that the parasite modifies host's behavior thereby increasing the probability that the parasite will pass from an intermediate host to its final host. We used the kissing bugs Triatoma pallidipennis and T. longipennis and two isolates of the Trypanosoma cruzi parasite (Chilpancingo and Morelos) to test these ideas. These insects are intermediate hosts of this parasite, which is the causal agent of Chagas disease. The Chilpancingo isolate is more pathogenic than the Morelos isolate, in the bugs. We expected that infected bugs would be more active and likely at detecting human-like odors. Given the differences in pathogenicity between isolates, we expected the Chilpancingo isolate to induce these effects more strongly and lead to higher parasite number than the Morelos isolate. Finally, infected bugs would gain less mass (a mechanism thought to increase bite rate, and thus transmission) than non-infected bugs. Having determined that both isolate haplotypes belong to the Tc1a group, we found that: (a) young instars of both species were more active and likely to detect human odor when they were infected, regardless of the isolate; (b) there was no difference in parasite abundance depending on isolate; and, (c) infected bugs did not end up with less weight than uninfected bugs. These results suggest that T. cruzi can manipulate the bugs, which implies a higher risk to contract Chagas disease than previously thought.


Assuntos
Comportamento Animal , Interações Hospedeiro-Parasita , Insetos Vetores/crescimento & desenvolvimento , Insetos Vetores/parasitologia , Triatoma/crescimento & desenvolvimento , Triatoma/parasitologia , Trypanosoma cruzi/parasitologia , Animais , Doença de Chagas/transmissão , Humanos , México
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