Wild mammals involved in the transmission of Trypanosoma cruzi and food sources of Triatoma sherlocki in an endemic region of northeastern Brazil.

The present study, carried out in the municipality of Gentio do Ouro, Bahia, Brazil aimed to evaluate which wild mammals may be involved in the transmission of T. cruzi and which are the blood sources for triatomines collected in the study area. PCR analysis of 31 wild mammals captured revealed T. cruzi infection in 6.4% (2/31): one specimen of the opossum Didelphis albiventris (1/3) and one of the rodent Kerodon rupestris (1/5); despite being more frequent in the area, no specimen of the rodent Thrichomys sp. (0/23) was infected. A total of 169 triatomines were captured. The conclusive detection of food sources was possible only for Triatoma sherlocki Papa et al., 2002 (n = 56), with evidence for: K. rupestris (35.7%), Gallus (17.9%), D. albiventris (14.3%), Homo sapiens (14.3%), Tropidurus hispidus (7.1%), Leopardus geoffroyi (5.3%), Conepatus semistriatus (1.8%), Thrichomys inermis (1.8%) and Rattus norvegicus (1.8%). Triatomines of the species T. sherlocki showed food eclecticism, including feeding on humans, with some of them being captured at dwellings. These facts make this triatomine a potential link for the transmission of T. cruzi between wild and anthropic environments, highlighting a latent risk of the reemergence of Chagas disease outbreaks.

Identification of novel Aedes aegypti odorant-binding protein 1 modulators by ligand and structure-based approaches and bioassays.

Arboviruses are a group of viruses (e.g. Dengue, Chikungunya and Yellow fever virus) that are transmitted by arthropod vectors, which Aedes aegipty is the vector of main viruses in Americas. This vector is responsible to 2.4 millions of arboviruses cases in Brazil with less than a thousand deaths annually. Despite of epidemiological data, arboviruses treatment is symptomatic and the vaccine control is not effective, which makes the vector control against A. aegipty a promising strategy to diseases control. One way to achieve this goal is to development of A. aegipty sensitive olfactory modulators. Odorant binding protein 1 from A. aegypti (AaegOBP1) is essential in sensory communication, and is the first filter in odorant selection, which makes this target promising to development of new repellents. For this reason, hierarchical virtual screening (ligand-based pharmacophore model and molecular docking) together volatility filter was applied at Sigma-Aldrich database (n = 126.851) to prioritize potential molecules to repellency assays. Three compounds showed adequate stereo-electronic requirements (QFIT> 81.53), score to AaegOBP1 binding site (Score > 36.0) and volatile properties and it was chosen for repellency assays. ZINC00170981 and ZINC00131924 showed a dose-response behavior, while ZINC01621824 did not showed activity in repellency assays. Finally, Molecular Dynamics (MD) was employed to hypothesize the stability of protein-ligand complexes. According to RMSD, RMSF and binding free energy data, ZINC00170981 and ZINC00131924 were able to stabilize AaegOBP1 binding-site during the trajectory by interactions with key residues such as His77, Leu89 and Trp114). Communicated by Ramaswamy H. Sarma.

Eco-epidemiology of vectorial Trypanosoma cruzi transmission in a region of northeast Brazil.

Chagas disease (CD) is a parasitic zoonosis endemic in Brazil. Despite virtual control of Triatoma infestans, the main domesticated vector of Trypanosoma cruzi, vectorial transmission by other triatomine species persists in some rural communities. This study aims to characterize triatomines role in transmitting T. cruzi to dogs and humans in the district of Santo Inácio, located in the northwest region of the state of Bahia, Brazil. It also describes environmental factors in housings associated with insect occurrence and assesses the perception, knowledge, and preventive practices adopted by the population regarding CD. Blood samples of humans and dogs, and biological samples of triatomines, were collected between November 2018 and February 2019 and subjected to the detection of T. cruzi by serological and molecular biology tests. Also, we applied a questionnaire to research the perception, knowledge, and local practices of people related to CD. The capture of triatomines in households was associated with exploratory variables of the questionnaires using multivariate logistic regression (p < 0.05). The 155 triatomines captured in the wild and domestic environment were of the species Triatoma sherlocki (n = 151), Panstrongylus sherlocki (n = 1) and Triatoma sordida (n = 3), and had a natural infection rate for T. cruzi by PCR of 18.5%, 100% and 0%, respectively. District residents (n = 126) were seronegative for T. cruzi, while 17.5% (7/40) of the dogs were seropositive. The fact that residents are aware that triatomines can "cause" CD was configured as a protection factor for residents according to the fitted logistic regression model (p = 0.04). However, respondents have limited perception and knowledge about the CD, prevention and control practices for triatomines in a household. The results suggest the existence of a domestic cycle of transmission of T. cruzi between triatomines and dogs, configuring a latent risk of infection to the human population of Santo Inácio. Studies that clarify the potential for the establishing of intrusive triatomines in households, surveillance actions for triatomines, and health education in rural communities are indispensable to prevent the reemergence of CD in vulnerable regions of Brazil and other American countries with similar epidemiological characteristics.

Identification of Bioactive Compounds against Aedes aegypti (Diptera: Culicidae) by Bioassays and in Silico Assays.

Most of the hematophagous insects act as disease vectors, including Aedes aegypti, responsible for transmitting some of the most critical arboviruses globally, such as Dengue. The use of repellents based on natural products is a promising alternative for personal protection compared to industrial chemical repellents. In this study, the repellent effect of essential oils extracted from Lippia thymoides, Lippia alba, Cymbopogon winterianus, and Eucalyptus globulus leaves was evaluated. Essential oils used showed repellent activity against Ae. aegypti in laboratory bioassays, obtaining protection rates above 70 % from 3.75 mg/mL and higher concentration for all analyzed oils. GC/MS identified 57 constituents, which were used in the ligand-based pharmacophore model to expose compounds with requirements for repellents that modulate mosquitoes behavior through odorant-binding protein 1 Ae. aegypti. Ligand-based pharmacophore model approach results suggested that repellent activity from C. winterianus, L. alba, and L. thymoides essential oils' metabolites is related to Citronelal (QFIT=26.77), Citronelol (QFIT=11.29), Citronelol acetate (QFIT=52.22) and Geranil acetate (QFIT=10.28) with synergistic or individual activity. E. globulus essential oil's repellent activity is associated with Ledol (0.94 %; QFIT=41.95). Molecular docking was applied to understand the binding mode and affinity of the essential oils' data set at the protein binding site. According to molecular docking, Citronelol (ChemPLP=60.98) and geranyl acetate (ChemPLP=60.55) were the best-classified compounds compared to the others and they can be explored to develop new repellents.

Clinical, epidemiological and transmission cycle aspects of leishmaniasis urbanization in Barreiras, Bahia, Brazil.

Leishmaniasis remains one of the world's leading infectious diseases and a public health problem for Bahia and Brazil. We made a retrospective cohort study of leishmaniasis cases reported between 2007 and 2016 in the Barreiras city, an important agribusiness city whose urbanization process was recent. Leishmaniasis presented epidemiological data with similar characteristics of the disease in other regions of the Brazil, that is, with the highest prevalence of visceral leishmaniasis found in children, while cutaneous leishmaniais was found in adults. The disease presented an urban configuration with wide distribution in the Barreiras city. We found the vectors of the different clinical forms of the disease occurring in the urban area of Barreiras city, particularly the sand fly of the Lutzmyia longipalpis, Evandromyia sallesi and Nyssomyia intermedia species. More studies will be necessary to indentify whether these species are really incriminated in the urban transmission of the parasites in the urban areas. This study indicates the places of the spatio-temporal greatest occurrence and transmission of the disease in the urban zones of Barreiras city.

Seroepidemiological survey of canine visceral leishmaniasis in a continental island of northeast Brazil / Investigação soroepidemiológica da leishmaniose visceral canina em uma ilha continental do Nordeste do Brasil

Introduction: Visceral leishmaniasis (VL) is endemic disease in the neighboring municipalities of the continental island Ilha de Maré, Salvador, Bahia, Brazil. Nevertheless, VL has not been reported in the island itself. Objective: the present study aimed to investigate the seroprevalence and clinical signs of Canine Visceral Leishmaniasis (CVL) and to identify the sand fly population present in the village of Botelho, Ilha de Maré. Methodology: sera of local dogs were tested for anti-Leishmania IgG by immunoassays (screening with TR DPP ™ rapid test and confirmatory with indirect ELISA, Bio-Manguinhos/Fiocruz) and an entomological survey was conducted to estimate and identify the phlebotomine fauna of the region. Results: seven out of 106 samples (6.6%) were positive using rapid test. These positive samples were sent to the Central Laboratory of Bahia for confirmation by indirect ELISA. However, all samples presentednegative results. Nine specimens of Pressatia choti, subfamily Phlebotominae were identified, being this species frequently found in areas with cutaneous leishmaniasis transmission in Brazil. Conclusion: although this work did not confirm the presence of CVL in Ilha de Maré, new serological and entomological studies in a larger area are required for the maintenance of the epidemiological surveillance in the emphasized insular area.

Introdução: Leishmaniose Visceral (LV) é uma doença endêmica em municípios vizinhos à Ilha de Maré, situada na plataforma continental do município de Salvador, Bahia, Brasil. Entretanto, casos de LV não tem sido notificados nesta Ilha. Objetivo: O presente trabalho objetivou investigar a soroprevalência e sinais clínicos de Leishmaniose Visceral Canina (LVC) e identificar a população de flebótomos presentes no povoado de Botelho, Ilha de Maré. Metodologia: soro de cães locais foram testados para IgG anti-Leishmania por imunoensaios (triagem com teste rápido TR DPP™ e confirmatório com Elisa Indireto, Bio-Manguinhos/Fiocruz) e uma investigação entomológica foi conduzida para estimar e identificar a fauna flebotomínea da região. Resultados: sete de 106 amostras (6,6%) foram positivas usando o teste rápido. As amostras positivas foram encaminhadas ao Laboratório Central da Bahia para a confirmação por ELISA indireto. Entretanto, essas amostras apresentaram resultado negativo. Foram encontrados nove exemplares da espécie Pressatia choti, subfamília Phlebotominae, espécie frequentemente encontrada em áreas de transmissão de leishmaniose cutânea no Brasil. Conclusão: apesar deste trabalho não ter confirmado a presença de LVC na Ilha de Maré, novos inquéritos sorológicos e analises entomológicas em uma maior área são necessários para a manutenção de uma vigilância epidemiológica na região insular em destaque.

Xenodiagnosis on dogs with visceral leishmaniasis: Canine and sand fly aspects related to the parasite transmission.

One of the main limitations for the effective control of canine leishmaniasis in endemic areas is the difficulty in identifying infectious dogs. The objective of this study was to determine factors, related to dogs and to parasite detection in sand flies, which are associated with the positive xenodiagnosis of Leishmania infantum using the vector Lutzomyia longipalpis. The xenodiagnosis was performed in 50 owned dogs residing in endemic areas, which were divided into three different groups: G1-26 dogs proved to be infected and classified by severity of VL clinical signs on physical examination; G2-15 dogs proved to be infected and classified by severity of clinical signs and intensity of laboratory abnormalities; G3-nine dogs that were seropositive for anti-Leishmania IgG in ELISA tests. Parasite search in the sand flies after having fed on dogs in the xenodiagnosis was performed by both methodologies, PCR and dissection followed by microscopy. In G1, 58% (15/26) of dogs were able to transmit Leishmania to the vector, when parasite detection in sand flies were performed by PCR technique, 5 days after blood meal, whereas in G2, 53% (8/15) transmitted the parasite to the vector, however, confirmation was performed by direct observation of parasite through optical miscroscopy held 10 days after blood meal. Rate of infectiousness of dogs to sand flies was positively associated to severity of disease (p=0.042 and p=0.040), regardless the method used for clinical classification or for parasite detection in sand flies after xenodiagnosis. In G1 30% (3/10) of dogs with subclinical infection were infectious to the vector, while 80% (12/16) of dogs with clinical disease were also infectious. Even more, 17% (1/6) of dogs that had moderate disease were infectious to the sand flies, while 78% (7/9) of dogs with severe disease were infectious in G2. Still in G2, the proportion of sand flies infected (grade of infectiousness) was significantly lower (p=0.0098) when they fed on dogs with moderate disease (1%) in comparison with dogs with severe disease (38%). The dogs from G3 presented a rate of infectiousness of 11% (1/9), demonstrating that the indirect ELISA is not a good indicator of infectiousness and, therefore, should not be used as a confirmatory test for the euthanasia of dogs, as it is currently done in Brazil.

Identification of biomarkers in the hair of dogs: new diagnostic possibilities in the study and control of visceral leishmaniasis.

Visceral leishmaniasis (VL) is a zoonosis whose etiologic agent in the Americas is Leishmania infantum, and dogs are the main host. Research and innovation in diagnostic techniques are essential to improve the surveillance and control of VL in endemic areas. The present study investigates the profile of the volatile organic compounds (VOCs) emitted by healthy dogs and by dogs infected by L. infantum to detect variations in the VOCs that may be used as biomarkers in the diagnosis of VL. In total, 36 dogs were selected from an endemic area and divided into three groups: G1, not infected with L. infantum; G2, infected without clinical signs of VL; and G3, infected with clinical signs of VL. To analyze the profiles of the VOCs emitted by dogs from the three groups, solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used. Variations were observed between the profiles of the VOCs emitted in the three groups studied, and they also differentiated infected animals with or without clinical signs. Six VOCs were identified as potential biomarkers of infection, with significant variations between healthy dogs (G1) and infected dogs (G2 + G3). The detection of variations between groups G2 and G3 suggested that the profiles of some VOCs may be related to the type of immune response and the parasite load of the infected dogs. This study demonstrated the possibility of analysis of VOCs as biomarkers of VL in diagnostic, clinical, and epidemiological work.

A laboratory evaluation of alcohols as attractants for the sandfly Lutzomyia longipalpis (Diptera:Psychodidae).

BACKGROUND: The potential attraction from 1-octen-3-ol for sandflies has been documented; however, studies using other primary alcohols are limited. FINDINGS: We used a wind tunnel to compare the activation and attractive behaviors in male and female Lutzomyia longipalpis using 1-octen-3-ol and three additional alcohols, 1-octanol, 1-heptanol and 1-nonanol at three different concentrations: neat (100%) and diluted in hexane (10% and 50%). The compounds 1-octen-3-ol and 1-nonanol induced a clear concentration-dependent activation and attraction response in females. In males, 1-octen-3-ol, 1-nonanol and 1-heptanol yielded the same results. CONCLUSIONS: L. longipalpis is attracted to 1-octen-3-ol, 1-nonanol and 1-heptanol, which are found in many plant volatiles.

Primeiro relato da ocorrência de evandromyia sallesi e evandromyia cortelezzii (diptera: psychodidae) na região metropolitana de Salvador, Bahia, Brasil / First report of the occurrence of evandromyia sallesi e evandromyia cortelezzii (diptera: psychodidae) at the metropolitan area of the city of Salvador, Bahia state, Brazil / Primer reporte de ocurrencia de evandromyia sallesi y evandromyia cortelezzii (díptera Psychodidae) en la región metropolitana de la ciudad de Salvador, estado de Bahia, Brasil

Este é o primeiro relato da ocorrência de Evandromyia sallesi (Galvão e Coutinho) e Evandromyia cortelezzii (Brèthes) na região metropolitana de Salvador, Bahia. Os flebotomíneos foram capturados com armadilhas luminosas CDC, durante um estudo investigativo em 24 localidades. A vigilância entomológica foi realizada entre setembro/2009 e março/2010, sendo coletados 13 espécimes de cinco bairros diferentes e classificados dentro do gênero Evandromyia.

This is the first report of Evandromyia sallesi (Galvão e Coutinho) and Evandromyia cortelezzii (Brèthes) occurrence at the metropolitan area of Salvador, Bahia, Brazil. The sand flies were captured with CDC luminous traps, during an investigative study in 24 localities. The entomological survey was performed between September/2009 and March/2010, being thirteen specimens collected and classified into the genus Evandromyia, from five different neighborhoods.

Este es el primer relato de ocurrencia de Evandromyia sallesi (Galvão y Coutinho) y Evandromyia cortelezzii (Brèthes) en la región metropolitana de Salvador, Bahia. Los flebotominos fueron capturados con trampas de luz CDC durante un estudio de investigación en 24 localidades. El muestreo entomológico se realizó entre Septiembre/2009 y Marzo/2010, recolectando 13 ejemplares, de cinco barrios diferentes, clasificados en el género Evandromyia.

Positividade para leishmaniose visceral canina: existem fatores caninos que contribuem? / Positividad para la leishmaniasis visceral canina: ¿existen factores caninos que contribuyen? / Positivity for canine visceral leishmaniasis: are there canine factors contributing?

A leishmaniose visceral canina (LVC), doença endêmica no Litoral Norte do Estado da Bahia, vem sendo investigada em seus aspectos epidemiológicos, ambientais e sociais, buscando-se formas de minimizar a sua expansão. O presente estudo de caso-controle objetivou identificar características inerentes aos cães de área endêmica e correlacioná-las àpositividade para LVC. Foram avaliadas as fichas clínicas de 226 cães testados sorologicamente no Laboratório de Infectologia Veterinária da Universidade Federal da Bahia, por meio do teste ELISA para soropositividade para anticorpos antileishmania, nos anos de 2009 e 2010,sendo selecionados todos os casos positivos nesses dois anos, totalizando 23; foram escolhidos 27 controles negativos com base nas fichas dos animais testados sob as mesmas condições. A soropositividade foi correlacionada às variáveis sexo, idade, raça e procedência. Para a análise estatística, foi escolhido o Teste Exato de Fisher, realizado pelo software Stata versão 10, e calculados o p-valor, a odds ratio e o intervalo de confiança. Foi possível encontrar umarelação incipiente entre sexo masculino e soropositividade, bem como uma forte relação entre procedência e soropositividade para LVC. São necessários estudos com um maior número de cães, buscando-se relacionar estas características à positividade para LVC, como forma deconhecer características caninas que propiciem a infecção.

The Canine Visceral Leishmaniasis (CVL) an endemic disease in the northern coast of Bahia has been investigated in its epidemiological, environmental and social aspects. The investigation seeks to find ways to minimize its spread. This study aimed to evaluate some characteristics of dogs and to correlate them to the positivity for CVL, using a casecontrolstudy. The medical records of 226 dogs tested serologically through the use of ELISA kit for CVL were evaluated at the Laboratory of Veterinary Infectious Diseases at the Federal University of Bahia, during the years 2009 and 2010.The total of positive cases were 23. There were chosen 27 dogs that had negative results based on forms of animals tested in the same conditions. Seropositivity was associated with gender, age, breed and origin. The Fisher's Exact Test was performed for statistical analysis, using the software Stata version 10.The p-value was calculated and the odds ratio and confidence intervals as well. It was possible to find evidence of association between the male sex and positivity as well as a strong association between origin and seropositivity for CVL. Larger studies with a greater number of dogs are needed to investigate the characteristics of positive animals for CVL as a way of knowing canine factors that are conducive to disease.

La leishmaniasis visceral canina (LVC), una enfermedad endémica en lacosta norte de la Bahía, ha sido investigada por sus aspectos epidemiológicos, ambientales y sociales, buscando formas que minimizen su propagación. Este estudio de caso-control tuvo como objetivo identificar características inherentes a los perros del área endémica ycorrelacionarlas con la positividad para LVC. Se evaluaron las historias clínicas de 226 perros testados serológicamente en el Laboratorio de Infectología Veterinaria de la Universidad Federal de la Bahía, por medio del test ELISA para seropositividad para anticuerpos antileishmania, en los años 2009 y 2010, siendo seleccionados todos los casos positivos en esos dos años, totalizando 23, fueron seleccionados 27 controles negativos basados en los registros de los animales testados bajo las mismas condiciones. La seropositividad fue correlacionada con las variables sexo, edad, raza y origen. Para el análisis estadísticofue elegido el Test Exacto de Fisher, realizado con el software Stata versión 10, y calculado el p-valor, la oddsratio, e el intervalo de confianza. Fue posible encontrar una incipiente relación entre el sexo masculino y seropositividad, así como, una fuerte relación entre origen y seropositividad para LVC. Se necesitan estudios con un mayor número de perros, buscando relacionar estas características con la positividad para LVC, como una manera de conocer las características caninas que propician la enfermedad