Retrospective analysis of serum and nasal mucus from cattle in Northern Ireland for evidence of infection with influenza A virus

Eighty-four pairs of acute and convalescent serum samples collected in 1998 and 1999 from 17 outbreaks of respiratory disease, milk drop syndrome or diarrhoea in cattle were tested by haemagglutination inhibition against human influenza viruses A/Eng/333/80 (HIN1) and A/Eng/427/88 (H3N2). Antibodies to these viruses were present in the convalescent sera of 56.5 per cent and 58.8 per cent cattle tested, respectively, with 56 per cent of the animals seroconverting to one or both viruses. Titres were typically higher to A/Eng/427/88 (H3N2). Further testing of a subset of 21 of these serum pairs against the predominant H1N1 and H3N2 human and porcine strains circulating when the samples were collected revealed that the highest reactivity, in terms of both the magnitude of the recorded titres and the number of positive sera, was to human H3N2 strains. The titres to human H1N1 strains and to both porcine subtypes were low or absent. Attempts to isolate influenza A virus from nasal mucus or swab samples from 142 cattle from 46 cases of respiratory disease and/or milk drop syndrome by passage in embryonated specific pathogen-free eggs were unsuccessful.     

Detection of antibiotic residues and association of cefquinome residues with the occurrence of Extended-Spectrum β-Lactamase (ESBL)-producing bacteria in waste milk samples from dairy farms in England and Wales in 2011

Waste milk samples from 103 farms in England and Wales were examined for the presence of β-lactam antibiotics and ESBL-producing Enterobacteriaceae. Approximately 10 months after the initial sampling, further waste milk, environmental and faecal samples from farms shown to be positive for CTX-M Escherichia coli were investigated further. Isolates with an ESBL phenotype were tested by PCR for the presence of bla_CTX-M, bla_OXA, bla_SHV and bla_TEM genes. Isolates positive for bla_CTX-M were sequenced to determine CTX-M type. Representative isolates were further examined by PFGE, plasmid replicon typing and serotyping. Of particular interest, 21.4% of waste milk samples contained residues of the cephalosporin cefquinome, which was significantly associated with CTX-M bacteria. Such bacteria occurred in 5.8% of the waste milk samples (including 3.9% CTX-M E. coli). CTX-M types identified were 1, 14, 14b and 15, but none of the E. coli were serotype O25, the serotype of the human pandemic strain.     

Evaluation of the Breeding Soundness of Male Camels (Camelus dromedarius) via Clinical Examination,Semen Analysis,Ultrasonography and Testicular Biopsy: A Summary of 80 Clinical Cases

Male camel infertility is a heterogeneous disorder. A variety of factors may adversely affect sperm production and function and impair fertility. This study was designed to evaluate the sensitivity and specificity of ultrasonography and testicular biopsy in the evaluation of the breeding soundness of male dromedaries compared with results obtained by clinical examination and semen analysis. Eighty‐four male dromedary camels (5–15 years old) were used in this study during the rutting season (November–May). Four sexually mature male camels were used as controls. These animals were apparently healthy and had histories of normal fertility. Eighty infertile male camels were subjected to an algorithmic approach based on information collected during careful examinations of the camels' breeding histories, clinical examinations, testicular evaluations, testicular ultrasonographies, the results of the semen analyses and testicular biopsies to diagnose the camels' infertilities. The differences in the semen parameters between the control and infertile male camels were highly significant (p < 0.01). Regarding the diagnoses of male camel infertility, the results of testicular ultrasonographies and biopsies were compared with those from the semen analyses, and the accuracies of these tests were 92.5% and 90%, respectively. Additionally, the results of the testicular ultrasonographies were matched with those of the testicular biopsies of the infertile animals, and this comparison resulted in 85% accuracy. Testicular biopsy is a promising method that, along with a carefully performed history, clinical examination, an appropriate testicular ultrasonography procedure and semen analysis, can afford veterinarians the opportunity for more precise diagnosis and treatment of many dromedary infertility disorders.     

Experimental infection of turkeys with Mycoplasma gallisepticum of low virulence, transmissibility, and immunogenicity.

Three-week-old turkeys were inoculated intranasally with approximately 10(6) colony-forming units (CFU) of putative variant Mycoplasma gallisepticum (MG) strains M876, M35, or the virulent S6 reference strain. Uninoculated turkeys in each group served as contact sentinels. The hemagglutination-inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA) were used to determine serologic responses. MG was isolated from 100% and 92% of S6- and M876-inoculated turkeys, respectively, on day 7 PI. However, culture-positive rates among M876-inoculated turkeys declined more rapidly, transmission to contact sentinels took longer and occurred at lower rates, and serologic responses measured by HI and ELISA were lower than in S6-infected turkeys. Testing sera from inoculated turkeys for antibodies to MG in homologous and heterologous ELISA systems indicated that strain M876 was significantly (P less than 0.05) less immunogenic than S6 (days 62 and 95 PI), and that the homologous ELISA was more sensitive (P less than 0.005). MG strain M35 failed to infect turkeys in three attempts, even though the inocula used were viable on culture media.     

Enzyme reaction rates at limited water activities

A well-mixed powder consisting of dry urea and urease exposed to air containing discrete amounts of water vapor showed a release of carbon-14 dioxide above 60-percent relative humidity. The relative activity of urease followed the water-vapor adsorption isotherm of urease. The minimum amount of water required for the reaction observed was 1.3 moles per mole of side-chain polar groups of the urease protein.     

Duplication, deletion, and polymorphism in the sex-determining region of the mouse Y chromosome

The ZFY gene in the sex-determining region of the human Y chromosome encodes a "zinc-finger" protein that may be the testis-determining factor, TDF. Although the Y chromosomes of most placental mammals carry a single homolog of ZFY, the mouse Y chromosome has two homologs, both in the sex-determining (Sxr) region. Zfy-1 alone may suffice to determine maleness; Zfy-2 is dispensable, as it was deleted in an Sxr variant that retains sex-determining function but has lost other genes. Both loci mapped near the centromere of the mouse Y chromosome. The Y chromosomes of the subspecies Mus musculus musculus and M. m. domesticus were distinguishable by a Zfy-1 restriction fragment polymorphism, which can be used to study their differing interactions with autosomal sex-determining genes.     

Polyteny: A Source of Cryptic Speciation among Copepods

A large form of the copepod Pseudocalanus is found in two warm, semi-landlocked fiords in arctic Canada, together with a similar but smaller form attributable to the widespread P. minutus. The large form has the same chromosomne number as P. minutus, but has larger chromosomes and a higher nuclear DNA content. There are suggestions in the literature that other similar polytenic and cryptic species occur among copepods.     

The dispersal of Culicoides brevitarsis in eastern New South Wales and associations with the occurrences of arbovirus infections in cattle

Distributions of the vector Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae) (determined from light trap data) and 2 arboviruses (determined from seroconversions in sentinel cattle) were studied in eastern New South Wales in 1993–94. C brevitarsis was recorded progressively from endemic areas on the north coast, to Nowra on the south coast, and westward to Scone, in the Hunter Valley. C brevitarsis also survived through winter at Paterson, in the Hunter Valley. Its apparently focal reappearance in this marginal area had no obvious effect on the broad pattern of its progression or the dispersal of Akabane and bluetongue viruses. These viruses were first recorded from foci near Coffs Harbour, on the mid-north coast. Their first occurrences at different locations were associated with those of C brevitarsis, but not with each other. The viruses were found only within the recorded limits of the vector's distribution. Delays between the initial occurrence of C brevitarsis and first evidence of virus transmissions at locations ranged from 2 to 7 months. The delays decreased away from the points of focus and were negatively associated with the time of initial occurrence of the vector. Seroconversions to the viruses were related to the presence of C brevitarsis. However, the densities of C brevitarsis had no apparent effect on the initial numbers of cattle seroconverting to either virus. The results support the conclusion that the progressions of C brevitarsis and Akabane and bluetongue viruses were the result of gradual movements by the vector.