Virulent strains of Shiga toxin-producing Escherichia coli (STEC) serogroups O103 and O121 are considered adulterants in beef. Two high-resolution melting (HRM) real-time PCR assays were standardized for the specific detection discrimination potentially virulent avirulent E. O121. The HRM assay offered possibility to distinguish clearly STEC O103:H2 from O103:H25. two extensively validated usin...

Virulence variability was investigated by analyzing the experimental pathogenicity of seven Leishmania tropica strains isolated from human lesions in Syria, through the evaluation of the infective ability, growth pattern and pathogenicity. Two of the strains presented higher levels of macrophage infection, increased promastigote replication in culture medium and as well as amastigote multiplica...

BACKGROUND Newcastle disease (ND) is one of the most contagious and devastating diseases to poultry in the world. The causative agents are virulent strains of Newcastle disease virus (NDV), which belong to the genus Avulavirus, sub-family Paramyxoviridae, family Paramyxovirinae. Knowing the genomic and antigenic characteristics of virulent NDVs might contribute to ND control in China. RESULTS...

A procedure was developed for direct detection, isolation, and maintenance of plasmid-bearing virulent serotypes of Yersinia enterocolitica from different food sources. Plasmid-bearing virulent strains of Y. enterocolitica representing five serotypes were simultaneously detected and isolated from enriched swab samples of artificially contaminated pork chops, ground pork, cheese, and zucchini, u...

Four strains of Salmonella typhimurium avirulent for mice were found to be capable of acting as gene acceptors in transduction experiments. An attempt was made to transduce virulence to three strains, using a typical mouse-virulent strain of S. typhimurium as donor. Two of the strains which are adenine-dependent were successfully made virulent by transduction and simultaneously became adeninein...

The primary feature of vvIBDV is the ability to induce high mortality. Mortality ranges from 5% – 25% in broilers and 30% – 70% in layers. Surviving birds are severely affected with a high condemnation rate. vvIBDV induces clinical signs similar to Gumboro disease, which is induced by classical virulent strains of IBDV, except that the disease is more pronounced and acute in individual birds an...

Comparison of immune responses induced in cattle by virulent and attenuated strains of Mycobacterium bovis will assist in identifying responses associated with resistance or susceptibility to disease. Four strains of M. bovis, one which is virulent in guinea pigs (WAg201) and three which are attenuated in guinea pigs (an isoniazid-resistant strain [WAg405], ATCC 35721, and BCG) were compared fo...

To isolate and detect anthrax spores form soil in different regions of Iran in order to find the anthrax foci‚ a total of 668 environmental specimens were collected during 2003-2004. Bacterial endospores were extracted from soil specimens via flotation in distilled water, incubation at room temperature, filtration, heat shock and culture on blood agar and selective PLET media. Bacillus anthraci...