Transmission of Eurasian avian H2 influenza virus to shorebirds in North America.
(17/1054)
Influenza A virus of the H2 subtype caused a serious pandemic in 1957 and may cause similar outbreaks in the future. To assess the evolution and the antigenic relationships of avian influenza H2 viruses, we sequenced the haemagglutinin (HA) genes of H2 isolates from shorebirds, ducks and poultry in North America and derived a phylogenetic tree to establish their interrelationships. This analysis confirmed the divergence of H2 HA into two geographical lineages, American and Eurasian. One group of viruses isolated from shorebirds in North America had HA belonging to the Eurasian lineage, indicating an interregional transmission of the H2 gene. Characterization of HA with a monoclonal antibody panel revealed that the antigenicity of the Delaware strains differed from the other avian strains analysed. The data emphasizes the importance of avian influenza surveillance. (+info)
PCR detection, characterization, and distribution of virulence genes in Aeromonas spp.
(18/1054)
We found 73.1 to 96.9% similarity by aligning the cytolytic enterotoxin gene of Aeromonas hydrophila SSU (AHCYTOEN; GenBank accession no. M84709) against aerolysin genes of Aeromonas spp., suggesting the possibility of selecting common primers. Identities of 90 to 100% were found among the eight selected primers from those genes. Amplicons obtained from Aeromonas sp. reference strains by using specific primers for each gene or a cocktail of primers were 232 bp long. Of hybridization group 4/5A/5B (HG4/5A/5B), HG9, and HG12 or non-Aeromonas reference strains, none were positive. PCR-restriction fragment length polymorphism (PCR-RFLP) with HpaII yielded three types of patterns. PCR-RFLP 1 contained two fragments (66 and 166 bp) found in HG6, HG7, HG8, HG10, and HG11. PCR-RFLP 2 contained three fragments (18, 66, and 148 bp) found in HG1, HG2, HG3, and HG11. PCR-RFLP 3, with four fragments (7, 20, 66, and 139 bp), was observed only in HG13. PCR-amplicon sequence analysis (PCR-ASA) revealed three main types. PCR-ASA 1 had 76 to 78% homology with AHCYTOEN and included strains in HG6, HG7, HG8, HG10, and HG11. PCR-ASA 2, with 82% homology, was found only in HG13. PCR-ASA 3, with 91 to 99% homology, contained the strains in HG1, HG2, HG3, and HG11. This method indicated that 37 (61%) of the 61 reference strains were positive with the primer cocktail master mixture, and 34 (58%) of 59 environmental isolates, 93 (66%) of 141 food isolates, and 100 (67%) of 150 clinical isolates from around the world carried a virulence factor when primers AHCF1 and AHCR1 were used. In conclusion, this PCR-based method is rapid, sensitive, and specific for the detection of virulence factors of Aeromonas spp. It overcomes the handicap of time-consuming biochemical and other DNA-based methods. (+info)
Determining sources of fecal pollution in a rural Virginia watershed with antibiotic resistance patterns in fecal streptococci.
(19/1054)
Nonpoint sources of pollution that contribute fecal bacteria to surface waters have proven difficult to identify. Knowledge of pollution sources could aid in restoration of the water quality, reduce the amounts of nutrients leaving watersheds, and reduce the danger of infectious disease resulting from exposure to contaminated waters. Patterns of antibiotic resistance in fecal streptococci were analyzed by discriminant and cluster analysis and used to identify sources of fecal pollution in a rural Virginia watershed. A database consisting of patterns from 7,058 fecal streptococcus isolates was first established from known human, livestock, and wildlife sources in Montgomery County, Va. Correct fecal streptococcus source identification averaged 87% for the entire database and ranged from 84% for deer isolates to 93% for human isolates. To field test the method and the database, a watershed improvement project (Page Brook) in Clarke County, Va., was initiated in 1996. Comparison of 892 known-source isolates from that watershed against the database resulted in an average correct classification rate of 88%. Combining all animal isolates increased correct classification rates to > or = 95% for separations between animal and human sources. Stream samples from three collection sites were highly contaminated, and fecal streptococci from these sites were classified as being predominantly from cattle (>78% of isolates), with small proportions from waterfowl, deer, and unidentified sources ( approximately 7% each). Based on these results, cattle access to the stream was restricted by installation of fencing and in-pasture watering stations. Fecal coliforms were reduced at the three sites by an average of 94%, from prefencing average populations of 15,900 per 100 ml to postfencing average populations of 960 per 100 ml. After fencing, <45% of fecal streptococcus isolates were classified as being from cattle. These results demonstrate that antibiotic resistance profiles in fecal streptococci can be used to reliably determine sources of fecal pollution, and water quality improvements can occur when efforts to address the identified sources are made. (+info)
Establishment of the PCR system specific to Salmonella spp. and its application for the inspection of food and fecal samples.
(20/1054)
We established the PCR detection system specific to Salmonella species using Salmonella enterotoxin gene (stn). The detection limit was one bacterial cell per one gram of fecal and minced-meat samples using enrichment procedure by Tripticase soy broth or Salmonella enrichment broth, respectively. We concluded that this PCR system is useful for the practical application in the field of the public hygiene. (+info)
Pituitary growth hormones: further evidence for evolutionary conservatism based on immunochemical studies.
(21/1054)
Immunochemical relatedness of preparations of purified somatotropins (growth hormones) of somatotropins in pituitary extracts from various vertebrate species was investigated by applying an antiserum to a purified somatotropin from a submammalian species, the snapping turtle. With the exception of monkey somatotropin, all mammalian, reptilian, and avian preparations tested showed reactions of identity or near identity by immunodiffusion studies in agar gel. Radioimmunoassay employing labeled rat somatotropin as a tracer and for standards, revealed that these same pituitary preparations gave steep inhibition slopes that were parallel or nearly parallel to each other. Purified somatotropins or somatotropins in pituitary extracts of subreptilian species, including an amphibian and existing primitive fishes, showed partial yet substantial relatedness to mammalian (ray) or reptilian (turtle) somatotropins by both immunodiffusion and radioimmunoassay. Our evidence indicates that the immunochemical relatedness of somatotropins from various vertebrate species appears to be even closer than has been suggested previously, and that a high degree of conservation of structure occurs during evolution. (+info)
Respiratory diseases among agricultural industry workers in India: a cross-sectional epidemiological study.
(22/1054)
Epidemiological survey for respiratory diseases among agricultural industry workers, such as bakeries, poultry farms, granaries and a sugar refinery was carried out using a medical questionnaire on various respiratory symptoms such as cough, breathlessness, rhinitis. The questionnaire was filled up by two doctoral students during personal visits to these work environments. The survey revealed that 40-59% of workers in different occupational work environments suffered from one or more respiratory ailments. As much as 36-40% of the workers reported work-related symptoms which is close to similar data from Western countries. A higher incidence of respiratory disorders was recorded in workers with longer duration of employment. Older workers suffered more than the young ones. Family history of atopy was found to have least effect on the incidence of cough, breathlessness and rhinitis in the workers. Smoking was found to have definite impact on the incidence of cough and breathlessness (+info)
Animal products and K-ras codon 12 and 13 mutations in colon carcinomas.
(23/1054)
K-ras gene mutations (codons 12 and 13) were determined by PCR-based mutant allele-specific amplification (MASA) in tumour tissue of 185 colon cancer patients: 36% harboured mutations, of which 82% were located in codon 12. High intakes of animal protein, calcium and poultry were differently associated with codon 12 and 13 mutations: odds ratios (OR) and 95% confidence intervals (95% CI) for codon 12 versus codon 13 were 9.0 (2.0-42), 4.1 (1.4-12) and 15 (1.4-160), respectively. In case-control comparisons, high intakes of animal protein and calcium were positively associated with colon tumours harbouring codon 12 mutations [for animal protein per 17 g, OR (95% CI) = 1.5 (1.0-2.1); for calcium per 459 mg, 1.2 (0.9-1.6)], while inverse associations were observed for tumours with K-ras mutations in codon 13 [for animal protein 0.4 (0.2-1.0); for calcium 0.6 (0. 3-1.2)]. Transition and transversion mutations were not differently associated with these dietary factors. These data suggest a different dietary aetiology of colon tumours harbouring K-ras codon 12 and 13 mutations. (+info)
Relationship between IS901 in the Mycobacterium avium complex strains isolated from birds, animals, humans, and the environment and virulence for poultry.
(24/1054)
A total of 738 strains of Mycobacterium avium complex (MAC) were examined in biological experiments on poultry by use of PCR methods with primers for detection of the insertion sequence IS901. Serotype strains of MAC from all known 28 serotypes were examined. Further strains were isolated from human immunodeficiency virus (HIV)-negative and HIV-positive patients, 6 animal species, 17 bird species, and the environment. Of 165 strains virulent for poultry, characterized by generalized tuberculosis, 164 strains contained IS901, a result which is statistically highly significant (P, 0.01). The remaining 573 strains were nonvirulent; however, IS901 was present in 24 strains. From among 20 strains of serotypes 1, 2, and 3, IS901 was found in 15 strains, only 5 of which were virulent for poultry. The remaining 111 strains, of serotypes 4 to 28, were nonvirulent and did not incorporate IS901. None of the 152 strains isolated from humans was virulent for poultry, including 12 strains which were IS901 positive. (+info)