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Equine abortus salmonellosis is a bacterial disease that causes high abortion rates in susceptible equids and therefore significant economic losses. Although the tube agglutination test (TAT) is a commonly used serological test for S. Abortusequi, it is not highly specific or sensitive, and the development of more sensitive, specific and rapid assays is therefore urgently required. In this study, an indirect enzyme-linked immunosorbent assay (iELISA) was developed for the specific detection of flagellum protein (FljB) antibodies against S. Abortusequi. Negative sera from horses in China (n = 1030) were used to establish the baseline for a negative population, and reference antisera positive against other viruses or bacteria were used to test the cross reactivity of the technique. The performance of the FljB iELISA was evaluated against that of the standard TAT, and was tested using field serum samples. The FljB iELISA assay was 8–16 times more sensitive than TAT. ROC analysis showed that the FljB iELISA was accurate, with an area under the curve (AUC) = 0.9943 (95% CI, 0.9815–1.000). The diagnostic sensitivity (DSe) of the FljB iELISA was 98.9% (95% Cl, 93.84%–100.00%), which was higher than that of TAT (DSe 38.6; 95% CI, 29.14%–49.08%). The diagnostic specificity (DSp) of the iELISA was 100.0% (95% CI, 95.82%–100.0%). When the 508 clinical samples were tested, the FljB iELISA had a positive detection rate of 51.38% (261/508, 95% CI, 51.24%–51.51%), which was higher than that of TAT (44/508). We also performed a serological survey for S. Abortusequi infection, using a series of samples collected from across eighteen provinces of China in 2021. The results showed that all provinces except Jiangsu had a certain number of cases, and the positive rates ranged from 0% to 96.9%, indicating the wide spread of S. Abortusequi in China. The abovementioned results suggest that the FljB iELISA developed in this study is rapid, sensitive, specific, and repeatable and is likely to be a suitable test for large-scale serological surveys for the detection and control of S. Abortusequi infection. [ABSTRACT FROM AUTHOR]

To meet the needs of underground anti-seepage projects such as landfills better, the anti-seepage slurry modified by sodium carboxymethyl cellulose (CMC-Na) was prepared through laboratory experiments on the basis of the preliminary study of PBFC anti-seepage slurry. The main material of the slurry is bentonite modified by sodium carboxymethyl cellulose, cement, fly ash and auxiliary materials such as sodium carbonate and polycarboxylate superplasticizer. The optimal ratio of the basic components of the anti-seepage slurry was optimized by the orthogonal test method. The permeability coefficient of the slurry was tested by the self-made constant head permeameter, and the age-resistant compressive strength was tested by the electronic press. The optimal mass ratio of each component of 1 liter slurry is: 20–22% bentonite, 20–22% cement, 16% fly ash, 0.15–0.2% sodium carbonate, 0.15–0.2% sodium carboxymethyl cellulose, 0.3% polycarboxylate superplasticizer. The permeability coefficient of the slurry consolidation body for 28 days is less than 1 × 1 0 − 8 cm/s, and the unconfined compressive strength is 0.5–2.0 MPa. The performance indexes of the slurry are higher than those of the existing anti-seepage slurry, which can better meet the anti-seepage standard of urban landfill in China. [ABSTRACT FROM AUTHOR]