Resultado da pesquisa (6)

Termo utilizado na pesquisa genetic diversity

#1 - Unveiling Trypanosoma spp. diversity in cattle from the state of Rio de Janeiro: A genetic perspective

Abstract in English:

Cattle trypanosomiasis imposes significant economic burdens on the global livestock industry. The causative agents of this disease belong to the protozoan Trypanosoma genus. This study aims to perform detection (parasitological and molecular) and genetic characterization to analyze Trypanosoma spp. in cattle from 15 municipalities in the state of Rio de Janeiro, focusing on the 18S rDNA and Cathepsin-L (CatL) gene of Trypanosoma vivax and Trypanosoma theileri. A total of 389 blood samples from 15 dairy cattle farms in the state of Rio de Janeiro were collected, and DNA was extracted for subsequent PCR amplification of Trypanosoma spp. 18S rDNA and CatL genes. The resulting amplicons underwent sequencing and alignment for phylogenetic analysis, with comparisons made to GenBank isolates. Concerning parasitological analysis, blood smears presented 4.4% of positive cattle (n=17/389) for T. vivax and did not show any trypomastigote forms of T. theileri. The absolute frequency of Trypanosoma spp. through molecular detection targeting 18S rDNA was 11.6% (45/389). However, when performing species-specific PCRs, the T. vivax frequency, determined through CatL gene PCR, was 12.8%, and the T. theileri frequency was 3.6%. Phylogenetic analysis based on 18S rDNA revealed low diversity among T. vivax sequences, suggesting potential host segregation. This study emphasizes the high frequency of positive samples by PCR when compared to direct parasitological exams. Additionally, T. vivax phylogeny targeting 18S rDNA hints at sequence clustering related to host species. Importantly, this investigation unveils, for the first time in Rio de Janeiro’s cattle, the circulation of T. theileri lineage ThI, encompassing genotypes IIB and IF. This discovery expands our understanding of this parasite’s geographical distribution and genetic diversity.

Abstract in Portuguese:

A tripanossomíase bovina impõe significativos ônus econômicos à indústria pecuária global. Os agentes causadores dessa doença pertencem a protozoários do gênero Trypanosoma. Objetivou-se, com este estudo, realizar detecção (parasitológica e molecular) e caracterização genética de Trypanosoma spp. em bovinos de 15 municipalidades do estado do Rio de Janeiro, com foco na sequência 18S rDNA e no gene Cathepsin-L (CatL) de Trypanosoma vivax e Trypanosoma theileri. Um total de 389 amostras de sangue de 15 fazendas leiteiras no estado do Rio de Janeiro foram coletadas, e o DNA foi extraído para subsequente amplificação por PCR dos genes 18S rDNA e CatL de Trypanosoma spp. Os amplicons resultantes foram submetidos a sequenciamento e alinhamento para análise filogenética, com comparações realizadas com isolados do GenBank. No que se refere à análise parasitológica, os esfregaços de sangue apresentaram 4,4% de bovinos positivos (n=17/389) para T. vivax e não mostraram nenhuma forma tripomastigota de T. theileri. A frequência absoluta de Trypanosoma spp. através da detecção molecular visando 18S rDNA foi de 11,6% (45/389). No entanto, ao realizar PCRs específicos de espécies, a frequência de T. vivax, determinada por PCR do gene CatL foi de 12,8%, e a frequência de T. theileri foi de 3,6%. A análise filogenética com base no 18S rDNA revelou baixa diversidade entre as sequências de T. vivax, sugerindo uma possível segregação de hospedeiros. Este estudo enfatiza a alta frequência de amostra positiva pela PCR quando comparada com a parasitológica direta. Além disso, a filogenia de T. vivax direcionada ao 18S rDNA sugere agrupamento de sequências relacionado à espécie hospedeira. Importante destacar que esta investigação revela, pela primeira vez no gado do Rio de Janeiro, a circulação da linhagem ThI de T. theileri, abrangendo os genótipos IIB e IF. Esta descoberta amplia nosso entendimento sobre a distribuição geográfica e diversidade genética desse parasito.


#2 - Genetic diversity of Mycoplasma hyopneumoniae in finishing pigs in Minas Gerais

Abstract in English:

Mycoplasma hyopneumoniae is one of the most challenging respiratory pathogens involved with swine pneumonia worldwide, responsible for a chronic infection with high morbidity, which predisposes secondary bacterial infections in growing and finishing pigs. Advances in diagnostic techniques allowed identification of genetic characteristics associated with high antigenic and proteomic variability among bacterial strains. This study aimed to evaluate the genetic diversity of M. hyopneumoniae strains in lungs with pneumonic lesions obtained from 52 pig farms located in Minas Gerais, one of the largest swine production states in Brazil. Genotyping was performed using multilocus variable number of tandem repeat (VNTR) analysis (MLVA), targeting two loci encoding P97 and P146 adhesins VNTR. The results showed that this agent is widely disseminated in pig farms and there is a high polymorphism of M. hyopneumoniae variants circulating in the state of Minas Gerais. Different M. hyopneumoniae genotypes are randomly distributed in several regions of the state, with no specific geographic population structure pattern. M. hyopneumoniae association with viral agents was sporadic (3.17% with Influenza A and 1.9% with PCV2).

Abstract in Portuguese:

Mycoplasma hyopneumoniae é um dos patógenos respiratórios mais desafiadores envolvidos com pneumonia suína em todo o mundo. É responsável por uma infecção crônica de alta morbidade, que predispõe a infecções bacterianas secundárias nas fases de crescimento e terminação. Avanços nas técnicas diagnósticas permitiram a identificação de características genéticas do agente, associadas à alta variabilidade antigênica e proteômica entre cepas. Este estudo teve como objetivo examinar a ocorrência e diversidade genética de cepas de M. hyopneumoniae em pulmões com lesões pneumônicas em 52 granjas de suínos no estado de Minas Gerais, um dos maiores estados produtores de suínos do Brasil. A genotipagem foi realizada utilizando a técnica de “multilocus variable number of tandem repeat analysis” (VTNR/MLVA), usando dois loci que codificam VNTR das adesinas P97 e P146. Os resultados mostraram que esse agente está amplamente disseminado em granjas de suínos e que existe alto polimorfismo das variantes de M. hyopneumoniae circulando no estado de Minas Gerais. Diferentes genótipos de M. hyopneumoniae estão distribuídos aleatoriamente em várias regiões do estado, sem um padrão de estrutura populacional e geográfica específico. Associação de M. hyopneumoniae e agentes virais foi esporádica (3,17% com Influenza A e 1,9% com PCV2).


#3 - Genetic diversity of Anaplasma marginale in calves under natural transmission conditions in the Northeast region of Pará

Abstract in English:

The objective of the present study was to detect the genetic diversity of Anaplasma marginale strains in naturally infected calves from a rural property located in the northeastern region of the state of Pará, Eastern Amazon, which has a history of mortality due to anaplasmosis. Fourteen calves positive for A. marginale were selected using a semi-nested polymerase chain reaction for the target msp1α gene, with asymptomatic (n=3) and symptomatic (n=11) infections. After sequencing the samples, two genotypes were verified in the E and C regions and the structures in tandem repeats were determined. Nine different strains were found: eight related to the E genotype (α-β-β-Γ = one animal, asymptomatic; 16-F-17-F-F = two animals, symptomatic; α-β-F-F-F-F = one animal, asymptomatic; 31-62-62-61 = one animal, symptomatic; τ-10-3 = three animals, two symptomatic and one asymptomatic; α-β-β-β = one animal, symptomatic; τ-22 -13-18 = two animals, both symptomatic; β-β-β-BRA1-31 = two animals, both symptomatic), and one related to genotype C (23-24-25-31-27-27 = one animal, asymptomatic). Genotype E was predominant in 92.86% of the samples (13/14), followed by genotype C (7.14%). This study made it possible to detect the genetic diversity of A. marginale in calves from the selected dairy farm, in addition to identifying the BRA1 sequence in the animals of the present study, which was recently diagnosed in Minas Gerais, demonstrating the dispersion of A. marginale strains in herds from different Brazilian states. Genetic diversity of A. marginale was observed in both symptomatic and asymptomatic calves. There were no significant differences when clinical signs were compared to the genotype verified in the infected animals. The prevalence of pathogenicity was not observed.

Abstract in Portuguese:

O objetivo do presente trabalho foi detectar a diversidade genética de cepas de Anaplasma marginale em bezerros naturalmente infectados oriundos de uma propriedade rural localizada na região nordeste do estado do Pará, Amazônia Oriental, a qual apresentava histórico de mortalidade devido à anaplasmose. Foram selecionados 14 bezerros positivos para A. marginale pela técnica de semi-nested PCR (nPCR) para o alvo no gene msp1α, com infecção assintomática (n=3) e sintomáticos (n=11). Após o sequenciamento das amostras foram verificados dois genótipos nas regiões E e C, e determinadas as estruturas em tandem repeats. Nove diferentes estirpes foram encontradas, sendo oito relacionadas ao genótipo E (α-β-β-Γ = um animal, assintomático; 16-F-17-F-F = dois animais, sintomáticos; α-β-F-F-F-F = um animal, assintomático; 31-62-62-61 = um animal, sintomático; τ-10-3 = três animais, dois sintomáticos e um assintomático; α-β-β-β = um animal, sintomático; τ-22-13-18 = dois animais, sintomáticos; β-β-β-BRA1-31 = dois animais, sintomáticos) e uma relacionada ao genótipo C (23-24-25-31-27-27 = um animal, assintomático). O genótipo E foi predominante em 92,86% das amostras (13/14), seguido pelo genótipo C (7,14%). O estudo possibilitou a detecção da diversidade genética de A. marginale em bezerros dessa propriedade leiteira, além de identificar a sequência BRA1 nos animais do presente estudo, a qual foi diagnosticada recentemente em Minas Gerais, o que demonstra a dispersão das estirpes de A. marginale nos rebanhos de diferentes estados brasileiros. A diversidade genética de A. marginale foi observada tanto em bezerros sintomáticos quanto em assintomáticos e não houve diferença significativa quando se comparou os sinais clínicos ao genótipo verificado no animal infectado, não observando a prevalência de patogenicidade de estirpes.


#4 - Characteristics of virulence, resistance and genetic diversity of strains of Salmonella Infantis isolated from broiler chicken in Brazil

Abstract in English:

Salmonella Infantis is frequently associated with human infections worldwide and is transmitted by consumption of contaminated foods, particularly those of animal origin, especially the chicken meat. We aimed to evaluate virulence characteristics, antimicrobial resistance and the genetic similarity of 51 strains of S. Infantis isolated from samples of poultry origin. The strains were isolated from 2009 to 2010 in a company with full cycle of broiler’s production in the state of São Paulo, Brazil. The antimicrobial susceptibility test was performed and, by PCR, we evaluated the presence of the genes lpfA (hem-adhesion), agfA (hem-biofilm) and sefA (hem-adhesion) and resistance genes to beta-lactams (blaTEM, blaSHV, blaCTX-M and blaAmpC). The phylogenetic relationship was determined by RAPD-PCR method. Among the drugs tested, the highest percentages of resistance were to amoxicillin (35.3%) and to sulfonamide (15.7%). Eleven antimicrobial resistance patterns were identified (A1 to A11), none of them presented a multiresistance profile (> 3 antimicrobials classes). There was 100% of positivity for the agfA gene, 92.2% for the lpfA gene, and no strain presented the sefA gene. Most of the isolates showed similarities in virulence potential, since they were simultaneously positive for two studied genes, agfA and lpfA (92.2%, 47/51). Of the 18 (35.3%) strains resistant to antimicrobials of the β-lactam class, 10 (55.5%) were positive to blaAmpC gene, five (27.8%) for blaCTX-M, two (11.1%) to blaSHV and no strain presented the blaTEM gene. The phylogenetic evaluation has shown the presence of five clusters (A, B, C, D and E) with similarity greater than 80%, and three distinct strains which were not grouped in any cluster. Cluster B grouped 33 strains, all positive for lpfA and agfA genes, from both, the broiler farming facility and the slaughterhouse, persistent throughout all the study period. This cluster also grouped 18 strains clones with genetic similarity greater than 99%, all isolated in the slaughterhouse. The presence of virulence genes associated with persistent strains clones for a long period, warns to the possibility of S. Infantis to form biofilm, and should be constantly monitored in broilers’ production chain, in order to know the profile of the strains that may contaminate the final product and evaluate the hazards that represents to public health.

Abstract in Portuguese:

Salmonella Infantis é frequentemente associada a infecções humanas no mundo todo sendo transmitida pelo consumo de alimentos contaminados, principalmente aqueles de origem animal, com destaque para a carne de frango. Objetivou-se avaliar características de virulência, resistência antimicrobiana e a similaridade genética de 51 estirpes de S. Infantis isoladas em amostras de origem avícola. As estirpes foram isoladas no período de 2009 a 2010 em uma empresa com ciclo completo de produção de frango de corte, localizada no estado de São Paulo, Brasil. Foi realizado o teste de susceptibilidade antimicrobiana e pela técnica de PCR, foi avaliada a presença dos genes lpfA (fímbria‑adesão), agfA (fímbria-biofilme) e sefA (fímbria‑adesão) e os genes de resistência aos beta-lactâmicos (blaTEM, blaSHV, blaCTX-M e blaAmpC). A relação filogenética foi determinada pelo método de RAPD-PCR. Dentre as drogas testadas, os maiores percentuais de resistência foram para amoxacilina com 35,3% e sulfonamida com 15,7%. Onze perfis de resistência aos antimicrobianos foram identificados (A1 a A11), sendo que nenhum deles apresentou perfil de multirresistência (>3 classes de antimicrobianos). Houve 100% de positividade para o gene agfA, 92,2% para o gene lpfA e nenhuma estirpe apresentou o gene sefA. A maioria dos isolados apresentaram semelhanças no potencial de virulência, pois foram positivos simultaneamente para dois genes estudados, agfA e lpfA (92,2% - 47/51). Das 18 (35,3%) estirpes resistentes aos antimicrobianos da classe dos β-lactâmicos, 10 (55,5%) foram positivas para o gene blaAmpC, cinco (27,8%) para blaCTX-M, duas (11,1%) para blaSHV e nenhuma estirpe apresentou o gene blaTEM. A avaliação filogenética demonstrou a presença de cinco clusters (A, B, C, D e E) com similaridade superior a 80%, e três estirpes distintas que não foram agrupadas em nenhum dos clusters. O cluster B agrupou 33 estirpes, todas positivas para os genes lpfA e agfA, provenientes tanto do aviário quanto do matadouro frigorífico, persistentes durante todo o período do estudo. Este cluster ainda agrupou 18 estirpes clones com similaridade genética superior a 99%, todas isoladas no matadouro frigorífico. A presença dos genes de virulência, associada à persistência das estirpes clones durante um longo período do estudo, alertam para a possibilidade de S. Infantis em formar biofilme, devendo ser constantemente monitorada na cadeia de produção avícola, especialmente no ambiente de abate, de forma a conhecer o perfil das estirpes que podem contaminar o produto final e assim avaliar os perigos que representam para a saúde pública.


#5 - Genetic diversity of bovine viral diarrhoea virus (BVDV) from Peru and Chile, p.41-44

Abstract in English:

ABSTRACT.- Ståhl K., Benito A., Felmer R., Zuñiga J., Reinhardt G., Rivera H., Baule C. & Moreno-López J. 2009. Genetic diversity of bovine viral diarrhoea virus (BVDV) from Peru and Chile. Pesquisa Veterinária Brasileira 29(1):41-44. Joint Virology Research and Development Division, National Veterinary Institute and Swedish University of Agricultural Sciences Uppsala, Sweden. E-mail: Karl.Stahl@bvf.slu.se Twenty-five BVDV strains, detected in serum from persistently infected cattle from Peru (n=15) and Chile (n=10) were genetically characterized. The phylogenetic analysis based on the 5’ UTR showed that all 25 strains belonged to genotype 1. Twenty-three of the strains could further be subdivided into subtype 1b, and two out of ten Chilean strains into subtype 1a. In conclusion, in total 23 out of 25 strains analyzed were of genotype 1, subtype 1b. This is the predominant BVDV subtype in many countries all over the world, including USA. The close homology with previously described strains reflects the influence of livestock trade on the diversity of BVDV circulating within and between countries and continents. Peru and Chile have imported large numbers of cattle from USA and Europe, mostly with insufficient or lacking health documentation.

Abstract in Portuguese:

ABSTRACT.- Ståhl K., Benito A., Felmer R., Zuñiga J., Reinhardt G., Rivera H., Baule C. & Moreno-López J. 2009. Genetic diversity of bovine viral diarrhoea virus (BVDV) from Peru and Chile. Pesquisa Veterinária Brasileira 29(1):41-44. Joint Virology Research and Development Division, National Veterinary Institute and Swedish University of Agricultural Sciences Uppsala, Sweden. E-mail: Karl.Stahl@bvf.slu.se Twenty-five BVDV strains, detected in serum from persistently infected cattle from Peru (n=15) and Chile (n=10) were genetically characterized. The phylogenetic analysis based on the 5’ UTR showed that all 25 strains belonged to genotype 1. Twenty-three of the strains could further be subdivided into subtype 1b, and two out of ten Chilean strains into subtype 1a. In conclusion, in total 23 out of 25 strains analyzed were of genotype 1, subtype 1b. This is the predominant BVDV subtype in many countries all over the world, including USA. The close homology with previously described strains reflects the influence of livestock trade on the diversity of BVDV circulating within and between countries and continents. Peru and Chile have imported large numbers of cattle from USA and Europe, mostly with insufficient or lacking health documentation.


#6 - Genotype characterization of the horn fly Haematobia irritans from different Brazilian geographic regions based on randomly amplified polymorphic DNA (RAPD) analysis, p.1-5

Abstract in English:

ABSTRACT.- Brito L.G., Regitano L.C.A., Huacca M.E.F., Carrilho E. & Moya Borja G.E. 2007. Genotype characterization of the horn fly Haematobia irritans from different Brazilian geographic regions based on randomly amplified polymorphic DNA (RAPD) analysis. Pesquisa Veterinária Brasileira 27(1):1-5. Laboratório de Sanidade Animal, Embrapa Rondônia, BR 364 Km 5,5, Porto Velho, RO 78900-970, Brazil. E-mail: luciana@cpafro.embrapa.br Blood-sucking diptera are important parasites in bovine production systems, especially regarding confinement conditions. Haematobia irritans, the horn fly, is one of the most troublesome species within bovine production systems, due to the intense stress imposed to the animals. An important aspect while studying the variability within a species is the study of the geographic structure of its populations and, attempting to find out the genetic flow of Brazilian populations of horn fly, the RAPD technique, which is suited for this purpose, has been used. The use of molecular markers generated from RAPD made it possible to identify the geographic origin of samples from different Brazilian geographic regions, as well as to estimate the genotypic flow among the different Brazilian populations of the horn fly.

Abstract in Portuguese:

ABSTRACT.- Brito L.G., Regitano L.C.A., Huacca M.E.F., Carrilho E. & Moya Borja G.E. 2007. Genotype characterization of the horn fly Haematobia irritans from different Brazilian geographic regions based on randomly amplified polymorphic DNA (RAPD) analysis. Pesquisa Veterinária Brasileira 27(1):1-5. Laboratório de Sanidade Animal, Embrapa Rondônia, BR 364 Km 5,5, Porto Velho, RO 78900-970, Brazil. E-mail: luciana@cpafro.embrapa.br Blood-sucking diptera are important parasites in bovine production systems, especially regarding confinement conditions. Haematobia irritans, the horn fly, is one of the most troublesome species within bovine production systems, due to the intense stress imposed to the animals. An important aspect while studying the variability within a species is the study of the geographic structure of its populations and, attempting to find out the genetic flow of Brazilian populations of horn fly, the RAPD technique, which is suited for this purpose, has been used. The use of molecular markers generated from RAPD made it possible to identify the geographic origin of samples from different Brazilian geographic regions, as well as to estimate the genotypic flow among the different Brazilian populations of the horn fly.


Colégio Brasileiro de Patologia Animal SciELO Brasil CAPES CNPQ UNB UFRRJ CFMV