Further evaluation of an indirect enzyme-linked immunosorbent assay for the diagnosis of bovine tuberculosis   总被引：6，自引：0，他引：6  

V Ritacco  B López  L Barrera  A Nader  E Fliess  I N de Kantor 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1990,37(1):19-27

The sensitivity and specificity of an ELISA for the detection of bovine IgG anti-Mycobacterium bovis antibodies were 73.6% and 94.1%, respectively, as determined in 53 bacteriologically confirmed tuberculous cattle and 101 healthy cattle from a tuberculosis-free area. In addition, the results of ELISA and tuberculin tests in 149 cattle were compared with those of subsequent necropsy studies. Both tests failed to detect 2 animals with tuberculous lesions and positive culture; 3/12 cattle with M. bovis isolation and no lesions, and 2/7 with atypical mycobacterial infection reacted to tuberculin, but none had antibodies; in 128 cattle with neither lesions nor mycobacterial isolation, 6 were tuberculin reactors and 7 others had antibodies. Negative results were obtained by ELISA in 21/22 paratuberculous cattle. Antibodies were not detected in 88.9% to 96.4% of 697 cattle from two tuberculin negative herds of an endemic area. In a herd with proved M. bovis infection, distribution of seropositive animals in tuberculin and non-tuberculin reactors was similar. Antibody responses to cutaneous tuberculin stimuli were observed in 4 experimentally infected cattle, but only in 2/10 healthy controls after repeated PPD stimuli. Nine controls which had either received a single tuberculin dose or none showed no increase in antibody levels. The low sensitivity of this ELISA limits its usefulness as a diagnostic tool for bovine tuberculosis eradication campaigns. However, it could be helpful in epidemiological surveillance if its efficiency to identify infected herds is demonstrated.  相似文献   

Paratuberculosis in Holstein-Friesian cattle farms in Central Iran     

Shahmoradi AH  Arefpajohi R  Tadayon K  Mosavari N 《Tropical animal health and production》2008,40(3):169-173

Paratuberculosis is an important disease of ruminants with a worldwide distribution. In developing countries where funding constraints challenge establishment of control schemes, large losses are incurred on cattle farmers due to paratuberculosis. In this study, faecal specimens from Holstein-Friesian cows with progressed and moderate clinical paratuberculosis (N = 223) from 13 dairy farms in Isfahan, Central Iran, were subjected to bacterial culture. Culture growth diagnostic for M. avium subsp. paratuberculosis was found in cattle from nine of the 13 farms and in 71 of the cattle studied. These results illustrate the emergence of PTb in this region, and they imply that PTb should be given a higher priority for veterinary measures.  相似文献   

New worlds on the horizon: Earth-sized planets close to other stars     

Gaidos E  Haghighipour N  Agol E  Latham D  Raymond S  Rayner J 《Science (New York, N.Y.)》2007,318(5848):210-213

The search for habitable planets like Earth around other stars fulfills an ancient imperative to understand our origins and place in the cosmos. The past decade has seen the discovery of hundreds of planets, but nearly all are gas giants like Jupiter and Saturn. Recent advances in instrumentation and new missions are extending searches to planets the size of Earth but closer to their host stars. There are several possible ways such planets could form, and future observations will soon test those theories. Many of these planets we discover may be quite unlike Earth in their surface temperature and composition, but their study will nonetheless inform us about the process of planet formation and the frequency of Earth-like planets around other stars.  相似文献   

Possibility of using three invasive non-forest tree species as an alternative source for energy production     

Ibrahim M. Aref  Mohamed Z. Salem  Nader D. Shetta  Thobayet S. Alshahrani  Ramadan A. Nasser 《Journal of Wood Science》2017,63(1):104-114

Non-woody biomass species have high-energy potentials, which could be used for bioenergy production. Invasive species are species spreading into areas, where they are not native, consequently causing environmental and economic problems. Therefore, the present study evaluated the proximate, ultimate, chemical, and fuel characteristics of wood and charcoal of three invasive non-forest tree species in Saudi Arabia: Calotropis procera, Rhazya stricta, and Phragmites australis, which were compared with the wood of Acacia tortilis, a preferable local fuelwood. All these data were discussed to investigate the possibility of using the invasive plants for energy production. The thermal behavior of wood was analyzed using thermo-gravimetric and derivative thermo-gravimetric methods. Overall, compared with the wood of A. tortilis, the woods of R. stricta and P. australis are suitable for energy production. The charcoal produced from P. australis emitted less nitrogen (N) oxide than that of R. stricta.  相似文献