RESUMO

This study evaluated the influence of the bird's age on the quality of the shell and percentage of bacterial penetration in commercial eggs. White-shelled commercial eggs were used, laid by light laying hens in their first laying cycle at 21, 39, 51, and 62 weeks of age. Shell quality evaluations comprised: egg weight, specific gravity, percentage and thickness of shell, number and size of pores. For evaluations regarding bacterial penetration, strains of several enterobacterias and one salmonella were used, all of which resistant to Nalidixic acid (100µg/ml). The method employed for evaluation of bacterial penetration was filling the eggs with growth medium. The data were subjected to variance analysis with 5% of probability using SAS (Education Analytical Software, 2013). Eveb though increase in the laying hen's age caused reduction of the quality of eggshells, it failed to affect the percentage of penetration of the bacterial samples evaluated.(AU)

O presente estudo avaliou a influência da idade da ave sobre a qualidade da casca e na porcentagem de penetração bacteriana em ovos comerciais. Foram utilizados ovos brancos comerciais provenientes de poedeiras leves em primeiro ciclo de postura com 21, 39, 51 e 62 semanas de idade. As avaliações de qualidade da casca realizadas foram: peso do ovo, gravidade específica, porcentagem e espessura da casca, número e tamanho dos poros. Para as avaliações da penetração bacteriana, foram utilizadas cepas de diversas enterobactérias e uma salmonela, sendo todas resistentes ao ácido nalidíxico (100µg/mL). O método utilizado para a avaliação da penetração bacteriana foi por meio do preenchimento dos ovos com meio de cultura. Os dados foram submetidos à análise de variância com 5% de probabilidade utilizando-se o programa SAS - Statistical Analisys System (Education Analytical Software, 2013). O aumento da idade da poedeira promoveu a redução da qualidade da casca dos ovos, porém não foi capaz de influenciar a porcentagem de penetração das amostras bacterianas avaliadas.(AU)

Assuntos

RESUMO

This study evaluated the influence of the bird's age on the quality of the shell and percentage of bacterial penetration in commercial eggs. White-shelled commercial eggs were used, laid by light laying hens in their first laying cycle at 21, 39, 51, and 62 weeks of age. Shell quality evaluations comprised: egg weight, specific gravity, percentage and thickness of shell, number and size of pores. For evaluations regarding bacterial penetration, strains of several enterobacterias and one salmonella were used, all of which resistant to Nalidixic acid (100µg/ml). The method employed for evaluation of bacterial penetration was filling the eggs with growth medium. The data were subjected to variance analysis with 5% of probability using SAS (Education Analytical Software, 2013). Eveb though increase in the laying hen's age caused reduction of the quality of eggshells, it failed to affect the percentage of penetration of the bacterial samples evaluated.(AU)

O presente estudo avaliou a influência da idade da ave sobre a qualidade da casca e na porcentagem de penetração bacteriana em ovos comerciais. Foram utilizados ovos brancos comerciais provenientes de poedeiras leves em primeiro ciclo de postura com 21, 39, 51 e 62 semanas de idade. As avaliações de qualidade da casca realizadas foram: peso do ovo, gravidade específica, porcentagem e espessura da casca, número e tamanho dos poros. Para as avaliações da penetração bacteriana, foram utilizadas cepas de diversas enterobactérias e uma salmonela, sendo todas resistentes ao ácido nalidíxico (100µg/mL). O método utilizado para a avaliação da penetração bacteriana foi por meio do preenchimento dos ovos com meio de cultura. Os dados foram submetidos à análise de variância com 5% de probabilidade utilizando-se o programa SAS - Statistical Analisys System (Education Analytical Software, 2013). O aumento da idade da poedeira promoveu a redução da qualidade da casca dos ovos, porém não foi capaz de influenciar a porcentagem de penetração das amostras bacterianas avaliadas.(AU)

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Water stress can affect the yield in tomato crops and, despite this, there are few types of research aiming to select tomato genotypes resistant to the water stress using physiological parameters. This experiment aimed to study the variables that are related to the gas exchanges and the efficiency in water use, in the selection of tomato genotypes tolerant to water stress. It was done in a greenhouse, measuring 7 x 21 m, in a randomized complete block design, with four replications (blocks), being five genotypes in the F2BC1 generation, which were previously obtained from an interspecific cross between Solanum pennellii versus S. lycopersicum and three check treatments, two susceptible [UFU-22 (pre-commercial line) and cultivar Santa Clara] and one resistant (S. pennellii). At the beginning of flowering, the plants were submitted to a water stress condition, through irrigation suspension. After that CO2 assimilation, internal CO2, stomatal conductance, transpiration, leaf temperature, instantaneous water use efficiency, intrinsic efficiency of water use, instantaneous carboxylation efficiency, chlorophyll a and b, and the potential leaf water (Ψf) were observed. Almost all variables that were analyzed, except CO2 assimilation and instantaneous carboxylation efficiency, demonstrated the superiority of the wild accession, S. pennellii, concerning the susceptible check treatments. The high photosynthetic rate and the low stomatal conductance and transpiration, presented by the UFU22/F2BC1#2 population, allowed a better water use efficiency. Because of that, these physiological characteristics are promising in the selection of tomato genotypes tolerant to water stress.

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The present study evaluated a probiotic and a competitive exclusion product injected in ovo on day 18 of incubation together with Marek's disease vaccine in eggs of 56-week-old broiler breeders. Three experiments were carried out. The first trial evaluated the effect of treatments on hatchability, cecal colonization of Salmonella Heidelberg (SH), and intestinal mucosa immunity (immunoglobulin A levels in the intestinal fluid). The second trial evaluated the viability of the microorganisms in the products inoculated in a solution containing diluent and Marek's disease vaccine. The third trial evaluated the colonization of the cecal microbiota in non-challenged chickens during first four days of life by culturing cecal samples under aerobic and anaerobic conditions. Hatchability was not affected by the treatments. SH cecal counts were reduced in three-day-old broilers inoculated in ovo with the competitive exclusion product. Liver and spleen pool SH counts were not different among treatments. Broilers inoculated in ovo presented higher intestinal IgA titers 24 hours after SH challenge compared with the controls. When birds were not challenged, lower cecal microbial counts in aerobic culture were determined in the control group than in the probiotic group on day 3, and in the competitive exclusion group on day 2 when cultured in anaerobiosis. The products inoculated and diluted in the vaccine solution were viable at all analyzed periods when cultured in anaerobiosis. The results of this study suggest in-ovo inoculation is an effective route for the administration of the evaluated products, which effectively enhanced the broilers' immune response to a SH challenge, as shown by the increase in IgA titers, and the reduction in cecal Salmonella Heidelberg colonization with the in-ovo inoculation with the competitive exclusion product.(AU)

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RESUMO

The present study evaluated a probiotic and a competitive exclusion product injected in ovo on day 18 of incubation together with Marek's disease vaccine in eggs of 56-week-old broiler breeders. Three experiments were carried out. The first trial evaluated the effect of treatments on hatchability, cecal colonization of Salmonella Heidelberg (SH), and intestinal mucosa immunity (immunoglobulin A levels in the intestinal fluid). The second trial evaluated the viability of the microorganisms in the products inoculated in a solution containing diluent and Marek's disease vaccine. The third trial evaluated the colonization of the cecal microbiota in non-challenged chickens during first four days of life by culturing cecal samples under aerobic and anaerobic conditions. Hatchability was not affected by the treatments. SH cecal counts were reduced in three-day-old broilers inoculated in ovo with the competitive exclusion product. Liver and spleen pool SH counts were not different among treatments. Broilers inoculated in ovo presented higher intestinal IgA titers 24 hours after SH challenge compared with the controls. When birds were not challenged, lower cecal microbial counts in aerobic culture were determined in the control group than in the probiotic group on day 3, and in the competitive exclusion group on day 2 when cultured in anaerobiosis. The products inoculated and diluted in the vaccine solution were viable at all analyzed periods when cultured in anaerobiosis. The results of this study suggest in-ovo inoculation is an effective route for the administration of the evaluated products, which effectively enhanced the broilers' immune response to a SH challenge, as shown by the increase in IgA titers, and the reduction in cecal Salmonella Heidelberg colonization with the in-ovo inoculation with the competitive exclusion product.

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A new concept of luminescent host-guest materials was developed by introduction of Eu(3+) into COK-16, a HKUST-1 type hybrid metal-organic framework (MOF) with cation exchange properties. In Eu@COK-16, the luminescent ion resides in the pore system of the MOF. The luminescence properties of Eu@COK-16 have been studied based on excitation and emission, allowing analysis of intramolecular energy-transfer processes from the COK-16 host to the exchanged Eu(3+) ions. Both the framework trimesate (BTC) and encapsulated [PW12O40](3-) ions contribute to energy transfer. Since the antenna molecules (BTC) are part of the framework structure and [PW12O40](3-) ions only partly occupy one of the three types of cavities in the structure, a large fraction of the pore volume in this host sensitized luminescent MOF remains available for catalysis applications or adsorption of additional sensitizing molecules. The material structure was determined from a combination of elemental analysis, XAS, XRD, electron and luminescence spectroscopy.

RESUMO

A busca por substitutos para os inseticidas sintéticos tem estimulado muitos trabalhos científicos contemplando inclusive a utilização de óleos, extratos, ou constituintes ativos provenientes de plantas. Esta procura pode ser justificada pelo potencial inseticida associado à fácil degradação de seus constituintes, menor toxicidade ao homem e uma alternativa mais segura para o meio ambiente. Após a coleta e aquecimento dos frutos de Anacardium occidentale (Anacardiaceae) a 40°C, obteve-se um líquido da castanha de caju (LCC) que, depois de testado quanto à sua atividade larvicida, foi fracionado em coluna de sílica gel dando origem a oito frações, as quais foram codificadas como AO1 a AO8 e submetidas a ensaios larvicidas. Avaliou-se também sua toxicidade oral aguda em Rattus norvegicus. O LCC e as frações AO2 e AO3 apresentaram atividade larvicida para Aedes aegypti. As concentrações letais, CL50 e CL90 do LCC foram, respectivamente, de 6,55 e 10,98 ppm. Para AO2 e AO3, as CL50 e CL90 foram de 3,18 e 7,80 ppm, e de 3,57 e 10,47 ppm, respectivamente. Não foi observada nenhuma toxicidade do LCC e das frações para R. norvegicus. O LCC e as frações foram administrados por via oral na dose de 2000 mg/kg. Esses produtos apresentaram potencial larvicida sobre Ae. aegypti e nenhum sinal de toxicidade foi evidenciado nos parâmetros analisados.

The search for substitutes for synthetic pesticides has been the subject of many scientific publications, including considering the use of oils, extracts and active constituents from plants. This demand can be justified by the insecticide potential associated with an easy degradation of its constituents, lower toxicity to humans and, consequently, a safer alternative for the environment. After collecting and heating the Anacardium occidentale (Anacardiaceae) fruits at 40°C, they were tested to confirm their larvicidal activity. Then, it was fractionated in a silica gel column. The fractionation resulted in eight fractions, which were coded as AO1 to AO8. In this paper, the cashew nut shell liquid (CNSL) and its fractions were evaluated as to their biological activity in the third instar larvae of Aedes aegypti. The acute oral toxicity in Rattus norvegicus also was evaluated. CNSL and the AO2 and AO3 fractions presented larvicidal activity. The lethal concentrations, LC50 and LC90, of CNSL were, respectively, 6.55 and 10.98 ppm. The active fractions, AO2 and AO3, presented LC50 and LC90 of 3.18 and of 7.80 ppm, and 3.57 and 10.47 ppm, respectively. The LCC and the fractions were orally administered at a dose of 2000 mg/kg. These products showed larvicidal potential against Ae. aegypti and no sign of toxicity was evident in the parameters analyzed.

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The larvicidal potential of the crude ethanolic extracts (CEE) of the stem peel of Sapindus saponaria was evaluated against Rhipicephalus sanguineus. Lethal concentrations (LC), were calculated by preparing CEE solutions at different concentrations in distilled water. Larvae fasted for 14-21 days were utilized in the bioassays, after incubation of engorged females collected from infested environments frequented by dogs in several neighborhoods of Goiânia, GO. Bioassays were performed in a specially constructed biological chamber for testing botanical acaricides, acclimatized to 27±1°C, RH>80 percent. The larvae were counted on filter paper envelopes impregnated with the solutions or distilled water and larval mortality observed after 48h. S. saponaria showed good larvicidal activity (LC50 and LC99 of 1994 and 3922ppm, respectively) and the results demonstrated its potential as a botanical acaricide and an alternative control measure for R. sanguineus.

Avaliou-se a potencialidade larvicida do extrato-bruto etanólico (EBE) da casca do caule de Sapindus saponaria sobre Rhipicephalus sanguineus. Para o cálculo das concentrações letais (CL) foram preparadas soluções com diferentes concentrações do EBE dissolvido em água destilada. Foram utilizadas larvas em jejum com 14 a 21 dias, obtidas pela incubação de teleóginas, coletadas em ambientes infestados, freqüentados por cães de vários bairros de Goiânia. Os bioensaios foram realizados em uma câmara biológica para testes com acaricidas botânicos, climatizada a 27±1°C e UR>80 por cento. As larvas foram contidas em envelopes de papel filtro impregnados com as soluções (grupo teste) ou com água destilada (grupo-controle) e a mortalidade larval foi observada após 48h. S. saponaria demonstrou atividade larvicida satisfatória (CL50 e CL99 respectivamente de 1994 e 3922ppm) e os resultados demonstraram seu potencial como acaricida botânico e medida alternativa para o controle de R. sanguineus.

Assuntos

RESUMO

The larvicidal potential of the crude ethanolic extracts (CEE) of the stem peel of Sapindus saponaria was evaluated against Rhipicephalus sanguineus. Lethal concentrations (LC), were calculated by preparing CEE solutions at different concentrations in distilled water. Larvae fasted for 14-21 days were utilized in the bioassays, after incubation of engorged females collected from infested environments frequented by dogs in several neighborhoods of Goiânia, GO. Bioassays were performed in a specially constructed biological chamber for testing botanical acaricides, acclimatized to 27±1ºC, RH>80%. The larvae were counted on filter paper envelopes impregnated with the solutions or distilled water and larval mortality observed after 48h. S. saponaria showed good larvicidal activity (LC50 and LC99 of 1994 and 3922ppm, respectively) and the results demonstrated its potential as a botanical acaricide and an alternative control measure for R. sanguineus.(AU)

Avaliou-se a potencialidade larvicida do extrato-bruto etanólico (EBE) da casca do caule de Sapindus saponaria sobre Rhipicephalus sanguineus. Para o cálculo das concentrações letais (CL) foram preparadas soluções com diferentes concentrações do EBE dissolvido em água destilada. Foram utilizadas larvas em jejum com 14 a 21 dias, obtidas pela incubação de teleóginas, coletadas em ambientes infestados, freqüentados por cães de vários bairros de Goiânia. Os bioensaios foram realizados em uma câmara biológica para testes com acaricidas botânicos, climatizada a 27±1ºC e UR>80%. As larvas foram contidas em envelopes de papel filtro impregnados com as soluções (grupo teste) ou com água destilada (grupo-controle) e a mortalidade larval foi observada após 48h. S. saponaria demonstrou atividade larvicida satisfatória (CL50 e CL99 respectivamente de 1994 e 3922ppm) e os resultados demonstraram seu potencial como acaricida botânico e medida alternativa para o controle de R. sanguineus.(AU)

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The objective of the present study was to analyze and describe the phenotype of the antennal sensilla of Panstrongylus megistus, one of the epidemiologically most important species of triatomines in Brazil. Specimens from the Brazilian states of Goiás (GO), Minas Gerais (MG), and Rio Grande do Sul (RS) were compared, based on studies of four types of sensilla on three antennal segments: thick-walled trichoid (TK), thin-walled trichoid (TH), bristles (BR), and basiconica (BA). Discriminant analysis allowed the separation of the RS specimens from those of GO and MG. Multivariate discriminant analysis demonstrated that the sensilla of males differed from those of females, the variables with greatest weight being the BA of all three segments and the TK of flagellum 1. The basiconica sensilla were significantly more abundant in females, on all three segments. Antennal sensilla patterns also demonstrated significant differences among P. megistus specimens.

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RESUMO

The objective of the present study was to analyze and describe the phenotype of the antennal sensilla of Panstrongylus megistus, one of the epidemiologically most important species of triatomines in Brazil. Specimens from the Brazilian states of Goiás (GO), Minas Gerais (MG), and Rio Grande do Sul (RS) were compared, based on studies of four types of sensilla on three antennal segments: thick-walled trichoid (TK), thin-walled trichoid (TH), bristles (BR), and basiconica (BA). Discriminant analysis allowed the separation of the RS specimens from those of GO and MG. Multivariate discriminant analysis demonstrated that the sensilla of males differed from those of females, the variables with greatest weight being the BA of all three segments and the TK of flagellum 1. The basiconica sensilla were significantly more abundant in females, on all three segments. Antennal sensilla patterns also demonstrated significant differences among P. megistus specimens.

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Três alcalóides benzilisoquinolínicos, reticulina, coclaurina e N-acetilnorjuzifina foram isolados das cascas de caule de Ocotea duckei; do cálice foi isolado laureliptina, um alcalóide do tipo aporfínico. Essas substâncias foram isoladas por métodos cromatográficos e identificadas por espectroscopia de 1H e 13C NMR com o auxílio de técnicas 2-D como as de COSY, NOESY, HMQC e HMBC. Comparações com os dados de literatura foram também realizadas.

Three benzylisoquinoline alkaloids, reticuline, coclaurine, and N-acetyl norjuziphine, where isolated from the stem bark of Ocotea duckei, the calix yielded laurelliptine, an aporphine alkaloid. These substances were isolated by chromatographic methods and identified by 1H and 13C NMR spectroscopy with the aid of 2-D techniques such as COSY, NOESY, HMQC and HMBC. Comparison with literature data was also helpful.

RESUMO

It has been observed that formulations of deltamethrin developed for disinsectization of infested places and control of parasitic arthropods of bovines and equines have frequently been used by breeders of dogs to control ticks in their animals and kennels, but without due consideration of the correct dosage or means of application. With the purpose of evaluating the efficacy of this product on Rhipicephalus sanguineus, bioassays were realized with larvae at 27+/-1 degrees C, UR>80% and light period of 12 hours. The mortality and toxicological effects were observed for 30 h, at 6 h intervals. Important toxicological effects were observed on the larvae, such as lack of co-ordination, knock-down and paralysis followed by death, although the lethal capacity of the product after 30 h was low, with mean mortality of only 34%, 40.2%, 46% and 57.6% respectively, for the 0.5 ml/l; 1 ml/l; 2 ml/l/; and 3 ml/l dosages. There was no mortality in the control group. The results obtained did not indicate the use of this formulation, in the tested dosages, as a method of choice for R. sanguineus control.

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It has been observed that formulations of deltamethrin developed for disinsectization of infested places and control of parasitic arthropods of bovines and equines have frequently been used by breeders of dogs to control ticks in their animals and kennels, but without due consideration of the correct dosage or means of application. With the purpose of evaluating the efficacy of this product on Rhipicephalus sanguineus, bioassays were realized with larvae at 27+/-1 degrees C, UR>80% and light period of 12 hours. The mortality and toxicological effects were observed for 30 h, at 6 h intervals. Important toxicological effects were observed on the larvae, such as lack of co-ordination, knock-down and paralysis followed by death, although the lethal capacity of the product after 30 h was low, with mean mortality of only 34%, 40.2%, 46% and 57.6% respectively, for the 0.5 ml/l; 1 ml/l; 2 ml/l/; and 3 ml/l dosages. There was no mortality in the control group. The results obtained did not indicate the use of this formulation, in the tested dosages, as a method of choice for R. sanguineus control.

Observou-se que formulações de deltametrina, desenvolvidas para desinsetizar ambientes infestados ou para combate de artrópodes parasitas de bovinos e equinos, têm sido freqüentemente utilizadas por cinofilistas para combater carrapatos em seus cães, sem critério científico em relação às dosagens e formas de aplicação, nos canis e ambientes onde vivem. Com a finalidade de avaliar a atividade deste produto sobre Rhipicephalus sanguineus, realizaram-se bioensaios com larvas a 27±1°C, UR>80% e fotofase de 12h. A mortalidade e os efeitos toxicológicos foram observados durante 30h, a cada 6h. Constataram-se efeitos toxicológicos importantes nas larvas, tais como incoordenação, Knock-down e paralisia seguida por morte, todavia a capacidade letal do produto após 30h foi baixa, com mortalidade média de 34%, 40,2%, 46% e 57,6%, respectivamente, para as dosagens de 0,5ml, 1ml, 2ml, 3ml. Não houve mortalidade no grupo controle. Os resultados obtidos contra-indicam o uso da deltametrina nas dosagens testadas como medida eletiva para controle de R. sanguineus.

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The influence of the period of egg quiescence on the life cycle of Aedes aegypti (Linnaeus, 1762) (Diptera, Culicidae) was studied under laboratory conditions in order to improve the management of vector control. The eggs are known to be the most resistant stages during development, allowing a long survival of the mosquitoes under unfavorable climatic conditions. The experiments were performed in a biological chamber kept at 28 +/- 1 degrees C temperature, with 80 +/- 5% relative humidity and 12 hours of photophase. Data about the influence of different periods of quiescence on eclosion, larval and pupal development and the developmental cycle are presented. We observed a highly significant effect of the period of quiescence on larval eclosion. The period of quiescence had no influence on the duration of larval or pupal incubation. Eggs originating from the same period of quiescence showed significantly different periods of incubation. The larvae emerged in groups defined by the period of incubation. This group effect was significant during the cycle. In 99.8% of the cycles the variation was determined by incubation.

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Beauveria bassiana (Balsamo) Vuillemin (isolate CG306) was tested on 3rd instars of 9 Triatoma spp., 4 Rhodnius spp., 2 Panstrongylus spp. and Dipetalogaster maxima (Uhler) at 25 degrees C and 50% RH. Quantitative sporulation of the fungus on cadavers was studied at 25 degrees C and 97% RH. Mortality, estimates of survival time, and conidial production on cadavers differed significantly among the genera and species tested. Panstrongylus herreri Wygodzinsky, Dipetalogaster maxima, Triatoma picturata Usinger, Rhodnius robustus Larrousse, Rhodnius prolixus Stål, Triatoma infestans (Klug), and Triatoma brasiliensis Neiva were most susceptible to fungal infection. Most conidia per cadaver were produced on Triatoma williami Galvão, Souza & Lima and Triatoma lecticularia (Stål). Results indicate that B. bassiana (CG306) might be a candidate for control of important or potential vectors of Trypanosoma cruzi using the fungus as a bioinsecticide.

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Twenty three isolates of Beauveria bassiana and 13 isolates of Metarhizium anisopliae were tested on third instar nymphs of Triatoma infestans, a serious vector of Chagas disease. Pathogenicity tests at saturated humidity showed that this insect is very susceptible to fungal infection. At lower relative humidity (50%), conditions expected in the vector microhabitat, virulence was significantly different among isolates. Cumulative mortality 15 days after treatment varied from 17.5 to 97.5%, and estimates of 50% survival time varied from 6 to 11 days. Maintaining lower relative humidity, four B. bassiana and two M. anisopliae isolates were selected for analysis of virulence at different conidial concentrations and temperatures. Lethal concentrations sufficient to kill 50% of insects (LC50) varied from 7.1 x 10(5) to 4.3 x 10(6) conidia/ml, for a B. bassiana isolate (CG 14) and a M. anisopliae isolate (CG 491) respectively. Most isolates, particularly B. bassiana isolates CG 24 and CG 306, proved to be more virulent at 25 and 30 degrees C, compared to 15 and 20 degrees C. The differential virulence at 50% humidity observed among some B. bassiana isolates was not correlated to phenetic groups in cluster analysis of RAPD markers. In fact, the B. bassiana isolates analyzed presented a high homogeneity (> 73% similarity).

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An active entomologic survey was conducted by a team of trained health workers in a rural area endemic for Chagas' disease in central Brazil. They used pyrethrum as a flushing agent and 4,232 houses were inspected for triatomine bugs both inside and in the immediate environs. Houses with Triatoma infestans or evidence of an established colony were identified and defined as infested houses (cases). The building and environmental characteristics of 161 randomly selected infested houses were compared with 161 matched, noninfested houses (controls) that were the shortest distance from the infested house. Domestic and peridomestic potential risk factors associated with house infestation by Triatoma infestans were assessed by logistic regression analysis. Incomplete house construction (odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.5-4.1) was confirmed as a risk factor related to the presence or evidence of Triatoma infestans in the dwellings. The study also disclosed a statistically significant association between the presence of rats (OR = 1.6, 95% CI = 1.1-2.6) and indoor crop storage (OR = 2.3, 95% CI = 1.1-5.2) and house infestation. Further experimental field studies using tagged rodents should be conducted to assess their epidemiologic role in the domestic chain of Trypanosoma cruzi transmission.

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In order to study the sensitivity of the xenodiagnosis technique a comparison between natural and artificial xenodiagnosis methods was performed in 57 chronic phase chagasic patients (31 female), with ages ranging from 26 to 83 years. All patients had demonstrable antibodies against Trypanosoma cruzi. Forty first instar nymphs of Dipetalogaster maximus were used for each of both methods and for each patient. The positivity of xenodiagnosis artificial was significantly higher than the routine test method. These results did show that a single application of 40 bugs by the artificial method yielded a similar result than 3 applications of 40 bugs each, by the natural method. The positivity of xenodiagnosis was significantly higher in patients between 56-65 and 66-83 years old than at other ages. Males were predominant in this age group. These results showed the viability of artificial xenodiagnosis and its use in routine laboratory testing.

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