Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
Add more filters










Language
Publication year range
1.
Braz. j. biol ; 84: e257402, 2024. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1355856

ABSTRACT

Abstract Visceral leishmaniasis (VL) is an infectious disease predominant in countries located in the tropics. The prediction of occurrence of infectious diseases through epidemiologic modeling has revealed to be an important tool in the understanding of its occurrence dynamic. The objective of this study was to develop a forecasting model for the incidence of VL in Maranhão using the Seasonal Autoregressive Integrated Moving Average model (SARIMA). We collected monthly data regarding VL cases from the National Disease Notification System (SINAN) corresponding to the period between 2001 and 2018. The Box-Jenkins method was applied in order to adjust a SARIMA prediction model for VL general incidence and by sex (male or female) for the period between January 2019 and December 2013. For 216 months of this time series, 10,431 cases of VL were notified in Maranhão, with an average of 579 cases per year. With regard to age range, there was a higher incidence among the pediatric public (0 to 14 years of age). There was a predominance in male cases, 6437 (61.71%). The Box-Pierce test figures for overall, male and female genders supported by the results of the Ljung-Box test suggest that the autocorrelations of residual values act as white noise. Regarding monthly occurrences in general and by gender, the SARIMA models (2,0,0) (2,0,0), (0,1,1) (0,1,1) and (0,1,1) (2, 0, 0) were the ones that mostly adjusted to the data respectively. The model SARIMA has proven to be an adequate tool for predicting and analyzing the trends in VL incidence in Maranhão. The time variation determination and its prediction are decisive in providing guidance in health measure intervention.


Resumo A leishmaniose visceral (LV) é uma doença de natureza infecciosa, predominante em países de zonas tropicais. A predição de ocorrência de doenças infecciosas através da modelagem epidemiológica tem se revelado uma importante ferramenta no entendimento de sua dinâmica de ocorrência. O objetivo deste estudo foi desenvolver um modelo de previsão da incidência da LV no Maranhão usando o modelo de Média Móvel Integrada Autocorrelacionada Sazonal (SARIMA). Foram coletados os dados mensais de casos de LV através do Sistema de Informação de Agravos de Notificação (SINAN) correspondentes ao período de 2001 a 2018. O método de Box-Jenkins foi aplicado para ajustar um modelo de predição SARIMA para incidência geral e por sexo (masculino e feminino) de LV para o período de janeiro de 2019 a dezembro de 2023. Durante o período de 216 meses dessa série temporal, foram registrados 10.431 casos de LV no Maranhão, com uma média de 579 casos por ano. Em relação à faixa etária, houve maior registro no público pediátrico (0 a 14 anos). Houve predominância do sexo masculino, com 6437 casos (61,71%). Os valores do teste de Box-Pierce para incidência geral, sexo masculino e feminino reforçados pelos resultados do teste Ljung-Box sugerem que as autocorrelações de resíduos apresentam um comportamento de ruído branco. Para incidência mensal geral e por sexo masculino e feminino, os modelos SARIMA (2,0,0) (2,0,0), (0,1,1) (0,1,1) e (0,1,1) (2, 0, 0) foram os que mais se ajustaram aos dados, respectivamente. O modelo SARIMA se mostrou uma ferramenta adequada de previsão e análise da tendência de incidência da LV no Maranhão. A determinação da variação temporal e sua predição são determinantes no norteamento de medidas de intervenção em saúde.


Subject(s)
Humains , Mâle , Femelle , Nouveau-né , Nourrisson , Enfant d'âge préscolaire , Enfant , Adolescent , Leishmaniose viscérale/diagnostic , Leishmaniose viscérale/épidémiologie , Saisons , Brésil/épidémiologie , Incidence , Modèles statistiques
2.
Braz J Biol ; 82: e261840, 2022.
Article in English | MEDLINE | ID: mdl-35894350

ABSTRACT

The influence of abiotic factors on the abundance of microorganism populations in soil has been sparsely studied, especially regarding Bacillus thuringiensis (Bt) bacteria. Therefore, this research was aimed at analyzing the relationship between the chemical and textural characteristics of the soil of the Cerrado (savanna) of Maranhão State on the abundance of Bacillus thuringiensis. Soil samples were collected in different municipalities in eastern Maranhão: São Mateus do Maranhão, Alto Alegre, Coroatá, Timbiras and Codó. The soil samples were obtained in the 0-0.1 m layer for soil fertility and texture analysis. Then, in the same area for the isolation of Bt, 1 g of soil was collected. The colonies obtained in the isolation that featured morphological characteristics of Bacillus spp. were visualized under phase contrast microscopy. Principal component analysis, clustering and correlations were peformed. Results: The sand content correlated positively with the Bacillus thuringiensis index (iBt). The cluster analysis allowed for verifying that the soils not showed iBt in function of high concentrations of aluminum (Al) and potential acidity (H+Al). Considering as these attributes (Al and H+Al) alter the availability of P in the soil, the abundance of Bacillus thuringiensis may have been impaired by the deficiency of this element in the environment. Conclusion: Bt has correlations with soil texture, and high concentrations of aluminum and potential acidity in the soil influencing the permanence of Bacillus thuringiensis in Maranhão eastern Cerrado.


Subject(s)
Bacillus , Sol , Aluminium , Brésil , Sol/composition chimique
3.
Braz J Biol ; 84: e257402, 2022.
Article in English | MEDLINE | ID: mdl-35081217

ABSTRACT

Visceral leishmaniasis (VL) is an infectious disease predominant in countries located in the tropics. The prediction of occurrence of infectious diseases through epidemiologic modeling has revealed to be an important tool in the understanding of its occurrence dynamic. The objective of this study was to develop a forecasting model for the incidence of VL in Maranhão using the Seasonal Autoregressive Integrated Moving Average model (SARIMA). We collected monthly data regarding VL cases from the National Disease Notification System (SINAN) corresponding to the period between 2001 and 2018. The Box-Jenkins method was applied in order to adjust a SARIMA prediction model for VL general incidence and by sex (male or female) for the period between January 2019 and December 2013. For 216 months of this time series, 10,431 cases of VL were notified in Maranhão, with an average of 579 cases per year. With regard to age range, there was a higher incidence among the pediatric public (0 to 14 years of age). There was a predominance in male cases, 6437 (61.71%). The Box-Pierce test figures for overall, male and female genders supported by the results of the Ljung-Box test suggest that the autocorrelations of residual values act as white noise. Regarding monthly occurrences in general and by gender, the SARIMA models (2,0,0) (2,0,0), (0,1,1) (0,1,1) and (0,1,1) (2, 0, 0) were the ones that mostly adjusted to the data respectively. The model SARIMA has proven to be an adequate tool for predicting and analyzing the trends in VL incidence in Maranhão. The time variation determination and its prediction are decisive in providing guidance in health measure intervention.


Subject(s)
Leishmaniose viscérale , Adolescent , Brésil/épidémiologie , Enfant , Enfant d'âge préscolaire , Femelle , Humains , Incidence , Nourrisson , Nouveau-né , Leishmaniose viscérale/diagnostic , Leishmaniose viscérale/épidémiologie , Mâle , Modèles statistiques , Saisons
4.
Braz. j. biol ; 81(4): 872-880, Oct.-Dec. 2021. tab, graf
Article in English | LILACS | ID: biblio-1153450

ABSTRACT

Abstract Bacillus thuringiensis is the most commonly used entomopathogen in the control of Aedes aegypti, which is a vector for different etiological agents that cause serious infections in humans. Several studies aim to isolate strains of this bacterium from different environments, with the perspective of selecting isolates with larvicidal activity for mosquitoes. Aiming at the insecticidal action of B. thuringiensis, the present study aimed to prospect B. thuringiensis of restinga and mangrove soils from the state of Maranhão, Brazil, with toxic potential for use in the biological control of Ae. aegypti. Bioassays were performed to determine the entomopathogenic activity of the bacilli against Ae. aegypti and lethal concentrations (LC50 and CL90) were estimated after the tests. Polymerase Chain Reaction and SDS-PAGE techniques were performed to verify the gene and protein content of the isolates, respectively. The soil of the mangrove and restinga ecosystems showed potential for obtaining B. thuringiensis. This isolate, in addition to having proteins with molecular mass similar to the toxins Cry and Cyt, also presented several diptera-specific genes cry and cyt, demonstrating that it has high potential to be used in the biological control of Ae. aegypti.


Resumo Bacillus thuringiensis é o entomopatógeno mais utilizado no controle do Aedes aegypti, vetor de diferentes agentes etiológicos que causam infecções graves em humanos. Diversos estudos têm como objetivo isolar cepas dessa bactéria de diferentes ambientes, com a perspectiva de selecionar isolados com atividade larvicida para mosquitos. Visando a ação inseticida de B. thuringiensis, o presente estudo teve como objetivo prospectar B. thuringiensis de solos de restinga e mangue do estado do Maranhão, Brasil, com potencial tóxico para uso no controle biológico de Ae. aegypti. Bioensaios foram realizados para determinar a atividade entomopatogênica do bacilo contra Ae. aegypti e as concentrações letais (CL50 e CL90) foram estimadas após os testes. As técnicas de Reação em Cadeia da Polimerase e SDS-PAGE foram realizadas para verificar o conteúdo de genes e proteínas dos isolados, respectivamente. Os solos dos ecossistemas de mangue e restinga apresentaram potencial para obtenção de B. thuringiensis. O isolado BtMA-750, obtido a partir da amostra de solo da restinga, foi interessantemente distinguido por sua alta toxicidade para Ae. aegypti. Este isolado, além de apresentar proteínas com massa molecular semelhante às toxinas Cry e Cyt, apresentou também diversos genes díptero-específicos cry e cyt, demonstrando que tem alto potencial para ser usado no controle biológico de Ae. aegypti.


Subject(s)
Humains , Animaux , Bacillus thuringiensis/génétique , Aedes , Brésil , Lutte biologique contre les nuisibles , Écosystème , Vecteurs moustiques , Larve
5.
Braz. j. biol ; 81(3): 557-565, July-Sept. 2021. tab, graf
Article in English | LILACS | ID: biblio-1153389

ABSTRACT

Abstract Cutaneous leishmaniasis (CL) is a neglected tropical disease with a wide distribution in the Americas. Brazil is an endemic country and present cases in all states. This study aimed to describe the occurrence, the underlying clinical and epidemiological factors, and the correlation of climatic variables with the frequency of reported CL cases in the municipality of Caxias, state of Maranhão, Brazil. This is a retrospective and descriptive epidemiological study based on data extracted from the Brazilian Information System of Diseases Notification, from 2007 to 2017. Maximum and minimum temperature, precipitation, and relative air humidity data were provided by the Brazilian National Institute of Meteorology. A total of 201 reported autochthonous CL cases were analyzed. The predominance of cases was observed in males (70.1%). The age range between 31 and 60 years old was the most affected, with 96 cases (47.9%). Of the total number of registered cases, 38.8% of the affected individuals were engaged in agriculture-related activities. The georeferenced distribution revealed the heterogeneity of disease occurrence, with cases concentrated in the Western and Southern regions of the municipality. An association was detected between relative air humidity (monthly mean) and the number of CL cases per month (p = 0.04). CL continues to be a concerning public health issue in Caxias. In this context, there is a pressing need to strengthen measures of prevention and control of the disease through the network of health services of the municipality, considering local and regional particularities.


Resumo A leishmaniose cutânea (CL) é uma doença tropical negligenciada, com ampla distribuição nas Américas. O Brasil é um país endêmico e apresenta casos em todos os estados. Este estudo teve como objetivo descrever a ocorrência, os fatores clínicos e epidemiológicos subjacentes e a correlação de variáveis climáticas com a frequência de casos de CL notificados no município de Caxias, estado do Maranhão, Brasil. Este é um estudo epidemiológico retrospectivo e descritivo, com base em dados extraídos da Notificação do Sistema Brasileiro de Informação de Doenças, de 2007 a 2017. Dados máximos e mínimos de temperatura, precipitação e umidade relativa do ar foram fornecidos pelo Instituto Nacional de Meteorologia. Foram analisados 201 casos de CL autóctones relatados. A predominância de casos foi observada no sexo masculino (70,1%). A faixa etária entre 31 e 60 anos foi a mais afetada, com 96 casos (47,9%). Do número total de casos registrados, 38,8% dos indivíduos afetados estavam envolvidos em atividades relacionadas à agricultura. A distribuição georreferenciada revelou a heterogeneidade da ocorrência da doença, com casos concentrados nas regiões oeste e sul do município. Foi detectada associação entre a umidade relativa do ar (média mensal) e o número de casos de CL por mês (p = 0,04). O CL continua sendo uma questão preocupante de saúde pública em Caxias. Nesse contexto, há uma necessidade premente de fortalecer medidas de prevenção e controle da doença por meio da rede de serviços de saúde do município, considerando as particularidades locais e regionais.


Subject(s)
Humains , Mâle , Adulte , Adulte d'âge moyen , Leishmaniose cutanée/épidémiologie , Brésil/épidémiologie , Études rétrospectives , Villes , Environnement
6.
Braz. j. biol ; 81(1): 114-124, Feb. 2021. tab, graf
Article in English | LILACS | ID: biblio-1153325

ABSTRACT

Abstract Entomopathogenic agents are viable and effective options due to their selective action against insects but benign effects on humans and the environment. The most promising entomopathogens include subspecies of Bacillus thuringiensis (Bt), which are widely used for the biological control of insects, including mosquito vectors of human pathogens. The efficacy of B. thuringiensis toxicity has led to the search for new potentially toxic isolates in different regions of the world. Therefore, soil samples from the Amazon, Cerrado and Caatinga biomes of the state of Maranhão were evaluated for their potential larvicidal action against Aedes aegypti. The isolates with high toxicity to mosquito larvae, as detected by bioassays, were subjected to histological evaluation under a light microscope to identify the genes potentially responsible for the toxicity. Additionally, the toxic effects of these isolates on the intestinal epithelium were assessed. In the new B. thuringiensis isolates toxic to A. aegypti larvae, cry and cyt genes were amplified at different frequencies, with cry4, cyt1, cry32, cry10 and cry11 being the most frequent (33-55%) among those investigated. These genes encode specific proteins toxic to dipterans and may explain the severe morphological changes in the intestine of A. aegypti larvae caused by the toxins of the isolates.


Resumo Os agentes entomopatógenos são alternativas viáveis e eficazes, devido à sua ação seletiva para insetos sendo inofensivos ao homem e ao meio ambiente. Dentre os entomopatógenos mais promissores, destacam-se as subespécies de Bacillus thuringiensis (Bt) amplamente utilizadas no controle biológico de insetos incluindo espécies de mosquitos vetores de agentes patogênicos ao homem. A eficiência da toxicidade de Bt incentiva a prospecção de novos isolados em diversas regiões do mundo. Desta forma, em busca de novos isolados de B. thuringiensis potencialmente tóxicos, amostras de solo provenientes dos biomas Amazônia, Cerrado e Caatinga do estado do Maranhão foram avaliadas em relação ao seu potencial larvicida para Aedes aegypti. Os isolados que provocaram elevada toxicidade para larvas do mosquito, detectada por bioensaios, foram avaliados em relação aos potenciais genes responsáveis pela atividade tóxica, além da avaliação de efeitos tóxicos no epitélio intestinal através de análises histológicas em microscopia de luz. Os novos isolados de Bt tóxicos para larva de A. aegypti amplificaram frequências diferentes de genes cry e cyt sendo os mais frequentes (55-33%) os cry4, cyt1, cry32, cry10 e cry11 dentre os investigados. Esses genes codificam para proteínas tóxicas específicas para ordem Diptera, e podem explicar as severas alterações morfológicas provocadas pelas toxinas dos isolados observadas no intestino das larvas de A. aegypti.


Subject(s)
Humains , Animaux , Bacillus thuringiensis/génétique , Aedes , Insecticides , Culicidae , Lutte biologique contre les nuisibles , Écosystème , Vecteurs moustiques , Larve
7.
Braz J Biol ; 81(3): 557-565, 2021.
Article in English | MEDLINE | ID: mdl-32876165

ABSTRACT

Cutaneous leishmaniasis (CL) is a neglected tropical disease with a wide distribution in the Americas. Brazil is an endemic country and present cases in all states. This study aimed to describe the occurrence, the underlying clinical and epidemiological factors, and the correlation of climatic variables with the frequency of reported CL cases in the municipality of Caxias, state of Maranhão, Brazil. This is a retrospective and descriptive epidemiological study based on data extracted from the Brazilian Information System of Diseases Notification, from 2007 to 2017. Maximum and minimum temperature, precipitation, and relative air humidity data were provided by the Brazilian National Institute of Meteorology. A total of 201 reported autochthonous CL cases were analyzed. The predominance of cases was observed in males (70.1%). The age range between 31 and 60 years old was the most affected, with 96 cases (47.9%). Of the total number of registered cases, 38.8% of the affected individuals were engaged in agriculture-related activities. The georeferenced distribution revealed the heterogeneity of disease occurrence, with cases concentrated in the Western and Southern regions of the municipality. An association was detected between relative air humidity (monthly mean) and the number of CL cases per month (p = 0.04). CL continues to be a concerning public health issue in Caxias. In this context, there is a pressing need to strengthen measures of prevention and control of the disease through the network of health services of the municipality, considering local and regional particularities.


Subject(s)
Leishmaniose cutanée , Adulte , Brésil/épidémiologie , Villes , Environnement , Humains , Leishmaniose cutanée/épidémiologie , Mâle , Adulte d'âge moyen , Études rétrospectives
8.
Braz J Biol ; 81(1): 114-124, 2021.
Article in English | MEDLINE | ID: mdl-32130286

ABSTRACT

Entomopathogenic agents are viable and effective options due to their selective action against insects but benign effects on humans and the environment. The most promising entomopathogens include subspecies of Bacillus thuringiensis (Bt), which are widely used for the biological control of insects, including mosquito vectors of human pathogens. The efficacy of B. thuringiensis toxicity has led to the search for new potentially toxic isolates in different regions of the world. Therefore, soil samples from the Amazon, Cerrado and Caatinga biomes of the state of Maranhão were evaluated for their potential larvicidal action against Aedes aegypti. The isolates with high toxicity to mosquito larvae, as detected by bioassays, were subjected to histological evaluation under a light microscope to identify the genes potentially responsible for the toxicity. Additionally, the toxic effects of these isolates on the intestinal epithelium were assessed. In the new B. thuringiensis isolates toxic to A. aegypti larvae, cry and cyt genes were amplified at different frequencies, with cry4, cyt1, cry32, cry10 and cry11 being the most frequent (33-55%) among those investigated. These genes encode specific proteins toxic to dipterans and may explain the severe morphological changes in the intestine of A. aegypti larvae caused by the toxins of the isolates.


Subject(s)
Aedes , Bacillus thuringiensis , Culicidae , Insecticides , Animaux , Bacillus thuringiensis/génétique , Écosystème , Humains , Larve , Vecteurs moustiques , Lutte biologique contre les nuisibles
9.
Braz J Biol ; 81(4): 872-880, 2021.
Article in English | MEDLINE | ID: mdl-33053121

ABSTRACT

Bacillus thuringiensis is the most commonly used entomopathogen in the control of Aedes aegypti, which is a vector for different etiological agents that cause serious infections in humans. Several studies aim to isolate strains of this bacterium from different environments, with the perspective of selecting isolates with larvicidal activity for mosquitoes. Aiming at the insecticidal action of B. thuringiensis, the present study aimed to prospect B. thuringiensis of restinga and mangrove soils from the state of Maranhão, Brazil, with toxic potential for use in the biological control of Ae. aegypti. Bioassays were performed to determine the entomopathogenic activity of the bacilli against Ae. aegypti and lethal concentrations (LC50 and CL90) were estimated after the tests. Polymerase Chain Reaction and SDS-PAGE techniques were performed to verify the gene and protein content of the isolates, respectively. The soil of the mangrove and restinga ecosystems showed potential for obtaining B. thuringiensis. This isolate, in addition to having proteins with molecular mass similar to the toxins Cry and Cyt, also presented several diptera-specific genes cry and cyt, demonstrating that it has high potential to be used in the biological control of Ae. aegypti.


Subject(s)
Aedes , Bacillus thuringiensis , Animaux , Bacillus thuringiensis/génétique , Brésil , Écosystème , Humains , Larve , Vecteurs moustiques , Lutte biologique contre les nuisibles
SELECTION OF CITATIONS
SEARCH DETAIL
...