Refinar búsqueda
Resultados 1-10 de 18
New insight of apparently healthy animals as a potential reservoir for Clostridium perfringens: a public health implication
2018
Hamza, Dalia | Dorgham, Sohad M. | Elhariri, Mahmoud | Elhelw, Rehab | Ismael, Elshaimaa
Introduction: Clostridium perfringens is commonly found in the gastrointestinal tract of animals and humans and continues to cause one of the most prevalent foodborne diseases in man. Material and Methods: A total of 355 samples were examined for the occurrence of C. perfringens: rectal swabs from cattle, sheep, and goats, fresh stool samples from diarrhoea sufferers having been in contact with these animals, irrigation water and soil samples from the husbandry sites, and preharvesting fresh produce from farms irrigated with the sampled water. All samples were collected from Cairo and Giza governorates, Egypt. PCR analysis was carried out with positive isolates using the α-toxin gene. Sequence analysis of the gene of C. perfringens isolates was performed using the neighbour-joining approach. Bootstrap analysis was executed with 1,000 resamplings. Results: 174 C. perfringens strains were isolated with a 49.01% prevalence. The highest prevalence of C. perfringens in apparently healthy animals was found in sheep (65.45%) followed by goats (58%), buffaloes (55%), and cattle (47.1%). Its prevalence in humans being in contact with these animals was 47.5%. The bacterium’s isolation from the soil and irrigation water was achieved in 40% and 31.7% of samples, respectively, posing a risk, particularly when the water and soil contact food in the field, shown by the fresh produce isolation of 40%. A significant relationship between the prevalence of C. perfringens in animal and environmental samples was identified (P < 0.05). A significant relationship was identified neither between animal species and C. perfringens prevalence, nor between the environmental source and C. perfringens prevalence (P > 0.05). All isolates were positive for the α-toxin gene by PCR. The sequence analysis and the phylogenetic relationship of the α-toxin genes from different samples revealed that C. perfringens from faeces of apparently healthy cattle, buffaloes, sheep, and goats is a significant threat in places where it can contaminate the soil and water. In addition, the sequence of C. perfringens from humans suffering from diarrhoea was found in the same cluster with the sequence from cows, goats, and sheep. Conclusion: The role of apparently healthy animals in transmitting C. perfringens to humans, either through being in direct or indirect contact via water or soil in the cultivation of vegetables and fruits, was demonstrated.
Mostrar más [+] Menos [-]Genetic analysis of the M gene of equine influenza virus strains isolated in Poland, in the context of the Asian-like group formation
2018
Kwaśnik, Małgorzata | Góra, Ilona M. | Żmudziński, Jan F. | Rola, Jerzy | Polak, Mirosław P. | Rożek, Wojciech
Introduction: Traditionally, evolutionary analysis of equine influenza virus (EIV) is based on the HA gene. However, the specificity of the influenza virus enables the classification of viral strains into different phylogenetic groups, depending on the gene being analysed. The aim of the study was to analyse phylogenetic paths of EIV based on M gene with reference to the HA gene. Material and Methods: M gene of Polish isolates has been sequenced and analysed along with all M sequences of EIV available in GenBank database. Phylogenetic analysis was performed using BioEdit, ClustalW, and MEGA7 softwares. Results: The clustering of the strains isolated not only from Asia but also from Europe into one common Asian-like group of EIV was observed. Twelve nucleotide substitutions in the M gene of strains from the Asian-like group were crucial for the evolutionary analysis. We also observed homology in the M gene of the Asian-like and H7N7 strains. Conclusions: M gene specific for the Asian-like group is present in strains recently isolated in Europe and Asia, which were classified previously in the Florida 2 clade based on HA. Therefore, Asian-like group does not seem to be assigned to a specific geographical region. Traces of H7N7 strains in more conservative genes like M of some contemporary EIV strains may indicate the link between the old phylogenetic group and recent H3N8 strains. Analysis of conservative genes may be more useful in tracking the direction of virus evolution than in the genes where the high variability rate may blur the original relationships.
Mostrar más [+] Menos [-]Genetic analysis of Toxocara spp. in stray cats and dogs in Van province, Eastern Turkey
2018
Oguz, Bekir | Ozdal, Nalan | Serdar Deger, M.
Toxocara canis and Toxocara cati are roundworms of dogs and cats. The purpose of this study was to investigate the infection caused by these ascarids in cats and dogs, using microscopic and molecular analysis methods. Adult ascarids were gathered from the faeces of dogs and cats in Van province, in 2015–2016. Existing keys and PCR sequencing of the ITS-2 fragment were used to identify the morphological features of the parasite species. It was observed that out of 20 adult ascarids, 17 and 3 were found to be Toxocara canis and Toxocara cati, respectively. The ITS-2 gene region was amplified by PCR to perform molecular analysis. Genotyping indicated that the dogs and cats were infected with T. canis and T. cati, respectively, and none had Toxascaris leonina. To the best of our knowledge, this is the first report on the molecular characteristics of adult ascaridoid nematodes from cats and dogs in Turkey. The molecular approaches established in this study enable molecular identification and genetic structure studies of the ascaridoids.
Mostrar más [+] Menos [-]Inactivated H5 antigens of H5N8 protect chickens from lethal infections by the highly pathogenic H5N8 and H5N6 avian influenza viruses
2018
Jin, Myongha | Jang, Yunyueng | Seo, Taehyun | Seo, Sang Heui
Introduction: Highly pathogenic Asian H5-subtype avian influenza viruses have been found in poultry and wild birds worldwide since they were first detected in southern China in 1996. Extensive control efforts have not eradicated them. Vaccination prevents such viruses infecting poultry and reduces the number lost to compulsory slaughter. The study showed the efficacy of inactivated H5 vaccine from the H5N8 virus against highly pathogenic H5N8 and H5N6 avian influenza viruses in chickens. Material and Methods: Reverse genetics constructed an H5 vaccine virus using the HA gene of the 2014 H5N8 avian influenza virus and the rest of the genes from A/PR/8/34 (H1N1). The vaccine viruses were grown in fertilised eggs, partially purified through a sucrose gradient, and inactivated with formalin. Chickens were immunised i.m. with 1 µg of oil-adjuvanted inactivated H5 antigens. Results: Single dose H5 vaccine recipients were completely protected from lethal infections by homologous H5N8 avian influenza virus and shed no virus from the respiratory or intestinal tracts but were not protected from lethal infections by heterologous H5N6. When chickens were immunised with two doses and challenged with homologous H5N8 or heterologous H5N6, all survived and shed no virus. Conclusion: Our results indicate that two-dose immunisations of chickens with H5 antigens with oil adjuvant are needed to provide broad protection against different highly pathogenic H5 avian influenza viruses.
Mostrar más [+] Menos [-]Cloning and expression of NS3 gene of Pakistani isolate type 2 dengue virus
2018
Yasmin, Farkhanda | Yaqub, Tahir | Idrees, Muhammad | Shahzad, Wasim | Hashmi, Abu Saeed | Aqil, Kiran | Mukhtar, Nadia | Zahoor, Muhammad Yasir | Akhtar, Naeem | Umar, Sajid
Dengue is one of the major emerging viral diseases in the world, with dramatic increases in reported cases in the last few decades and annual worldwide occurrence of approximately 390 million infections. It is a highly important mosquito-vectored disease and is a problem in tropical and subtropical areas of the world. The major aim of this study was to clone and express the dengue NS3 gene, in service to its therapeutic importance for the development of stable cell lines. Blood samples from dengue fever (DF) patients were collected and subjected to PCR amplification of the NS3 gene of dengue virus serotype-2 (DENV-2). The NS3 gene was amplified using gene specific primers and cloned in the TA cloning vectors. The gene was successfully expressed in mammalian expression vector pcDNA3.1. The current finding was different from a previously reported DENV-2 strain replicon constructed in different cells, in which the whole genetic material of the virus was used instead of an active protease gene, and which gave a low yield of replicon expressing cells. Recombinant NS3 could be used to produce an antibody that is possibly helpful for developing a single step diagnostic assay to detect the dengue virus NS3 antigen in sera of dengue patients.
Mostrar más [+] Menos [-]Trichinella spiralis: impact on the expression of Toll-like receptor 4 (TLR4) gene during the intestinal phase of experimental trichinellosis
2018
Wojtkowiak-Giera, Agnieszka | Wandurska-Nowak, Elżbieta | Derda, Monika | Jankowska, Wiesława | Jagodziński, Paweł P. | Hadas, Edward
Introduction: Toll-like receptors (TLRs) play a key role in the rapid activation of the innate immune response to a variety of pathogens. The aim of this study was to evaluate the effect of Trichinella spiralis infection on the level of expression of the tlr4 gene in mouse intestines during the intestinal phase of experimental trichinellosis. Material and Methods: The experimental material consisted of the small and large intestines of BALB/c mice infected with Trichinella spiralis sampled at 4, 8, and 16 days post infection (dpi). Results: A statistically significant increase was demonstrated in the tlr4 mRNA level isolated from the infected mice jejunum at 4, 8, and 16 dpi over the uninfected control. Moreover, at 4, 8, and 16 dpi in the jejunum of infected mice, a strong positive reaction for the presence of TLR4 protein compared with that of uninfected mice was observed. Conclusion: Infection with T. spiralis changes the expression of the tlr4 gene in the small intestine of the mouse host.
Mostrar más [+] Menos [-]Evaluation of real-time PCR based on SYBR Green I fluorescent dye for detection of Bacillus anthracis strains in biological samples
2018
Kędrak-Jabłońska, Agnieszka | Budniak, Sylwia | Szczawińska, Anna | Reksa, Monika | Krupa, Marek | Szulowski, Krzysztof
Introduction: The aim of the study was the application and evaluation of real-time PCRs based on the fluorescence of SYBR Green I intercalating dye for the detection of three Bacillus anthracis genes in contaminated liver and blood samples. The goals for detection were rpoB gene as a chromosomal marker, pag gene located on plasmid pXO1, and capC gene located on plasmid pXO2. Material and Methods: Five B. anthracis strains were used for the experiments. Additionally, single strains of other species of the genus Bacillus, i.e. B. cereus, B. brevis, B. subtilis, and B. megaterium, and strains of six other species were used for evaluation of the specificity of the tests. Three SYBR Green I real-time PCRs were conducted allowing confirmation of B. anthracis in the biological samples. Results: The observation of amplification curves in real-time PCRs enabled the detection of the chromosomally encoded rpoB gene, pag gene, and capC gene of B. anthracis. The specificity of the tests was confirmed by estimation of the melting temperature of the PCR products. The sensitivity and linearity of the reactions were determined using regression coefficients. Strains of other microbial species did not reveal real-time PCR products. Conclusion: All real-time PCRs for the detection of B. anthracis in biological samples demonstrated a significant sensitivity and high specificity.
Mostrar más [+] Menos [-]Development of a new RT-PCR with multiple primers for detecting Southern African Territories foot-and-mouth disease viruses
2018
Liu, Yali | Ding, Yao-Zhong | Dai, Jun-Fei | Ma, Bing | He, Ji-Jun | Ma, Wei-Min | Lv, Jian-Liang | Ma, Xiao-Yuan | Ou, Yun-Wen | Wang, Jun | Liu, Yong-Sheng | Chang, Hui-Yun | Wang, Yong-Lu | Zhang, Qiang | Liu, Xiang-Tao | Zhang, Yong-Guang | Zhang, Jie
Introduction: The extremely high genetic variation and the continuously emerging variants of foot-and-mouth disease virus (FMDV) of Southern African Territory (SAT) serotypes including SAT1, SAT2, and SAT3 make it necessary to develop a new RT-PCR for general use for monitoring viruses based on the updated genome information. Material and Methods: A FMDV SAT-D8 one-step RT-PCR was established based on the 1D2A2B genes of the SAT serotype viruses with a multiplex primer set. FMDV A, O, C, and Asia 1 serotypes, other vesicular disease viruses, inactivated SAT viruses, and 125 bovine, ovine, caprine and porcine tissue samples collected from the Chinese mainland were included for evaluating the assay. Results: The new RT-PCR was proven to be specific without cross-reactions with Eurasian FMDV, swine vesicular disease virus (SVDV), Seneca valley virus (SVV), or other common viral pathogens of cattle, sheep, goat, and pig. An around 257 bp-sized amplicon clearly appeared when the inactivated SAT viruses were detected. However, all 125 samples collected from FMDV-susceptible animals from the Chinese mainland which has not known SAT epidemics showed negative results. Conclusions: A FMDV SAT-D8 one-step RT-PCR is a promising method for primary screening for FMDV SAT serotypes.
Mostrar más [+] Menos [-]Clostridium perfringens spores in Polish honey samples
2018
Grenda, Tomasz | Grabczak, Magdalena | Goldsztejn, Magdalena | Kozieł, Nina | Kwiatek, Krzysztof | Pohorecka, Krystyna | Skubida, Marta | Bober, Andrzej
The aim of this study was examination of honey samples collected from apiaries situated in all Polish provinces for occurrence of Clostridium spp., especially C. perfringens. The study was carried out on 240 honey samples (15 samples/province). Estimation of Clostridium titre, its cultures and C. perfringens isolate characterisation were performed according to the standard PN-R-64791:1994. A multiplex PCR method for detection of genes coding cpa (α toxin), cpb (β), cpb2 (β2), etx (ε), iap (ι), and cpe (enterotoxin) toxins was used. Clostridium spp. was noticed in 56% (136/240) of samples, and its titres ranged between 0.1 g and 0.001 g. Clostridium perfringens occurrence was evidenced in 27.5% (66/240) of samples. All isolates were classified to toxinotype A. Evidence of a high number of positive samples with occurrence of Clostridium spp. indicates a potential risk to consumers’ health. The infective number of Clostridium spp. is unknown; however, the obtained results have shown that a risk assessment on the entire honey harvesting process should be made in order to ensure microbiological safety. Moreover, a detailed study should be undertaken on the antibiotic resistance of C. perfringens isolates from honey samples.
Mostrar más [+] Menos [-]Coronaviruses in avian species – review with focus on epidemiology and diagnosis in wild birds
2018
Miłek, Justyna | Blicharz-Domańska, Katarzyna
Coronaviruses (CoVs) are a large group of enveloped viruses with a single-strand RNA genome, which continuously circulate in mammals and birds and pose a threat to livestock, companion animals, and humans. CoVs harboured by avian species are classified to the genera gamma- and deltacoronaviruses. Within the gamma-CoVs the main representative is avian coronavirus, a taxonomic name which includes the highly contagious infectious bronchitis viruses (IBVs) in chickens and similar viruses infecting other domestic birds such as turkeys, guinea fowls, or quails. Additionally, IBVs have been detected in healthy wild birds, demonstrating that they may act as the vector between domestic and free-living birds. Moreover, CoVs other than IBVs, are identified in wild birds, which suggests that wild birds play a key role in the epidemiology of other gammaCoVs and deltaCoVs. Development of molecular techniques has significantly improved knowledge of the prevalence of CoVs in avian species. The methods adopted in monitoring studies of CoVs in different avian species are mainly based on detection of conservative regions within the viral replicase, nucleocapsid genes, and 3’UTR or 5’UTR. The purpose of this review is to summarise recent discoveries in the areas of epidemiology and diagnosis of CoVs in avian species and to understand the role of wild birds in the virus distribution.
Mostrar más [+] Menos [-]