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1

Origin and risk assessment of potentially harmful elements in river sediments of urban, suburban, and rural areas

100%
Yuan X., Li T., Li J., Ye H., Ge M.
Polish Journal of Environmental Studies
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2013
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tom 22
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nr 2
The Changjiang Delta Region is a rapidly urbanizing area in China. But this area still reveals different anthropogenic activities and urbanization levels. River sediments from urban, suburban, and rural areas were studied to characterize potentially harmful elements (PHEs) and their ecological risks. Chemical compositions of sediments were analyzed, which revealed pronounced differences in three areas. Al₂O₃, Fe₂O₃, CaO, and MgO were elevated in the urban sediments. Sediments from the rural area showed high organic matter. CaO and TOC of sediments fluctuated significantly in the suburban area. They are associated with the local geological provenance and sediment circumstance. The enrichments of PHEs in sediments of urban rivers were prevalent, among which Cd and As were prominent. Concentrations of PHEs in the suburban area fluctuated significantly. Lead and Cu were obviously enriched in this area. Rural sediments had relatively low concentrations of PHEs, which were also stable in the regional distribution, although As showed a slight enrichment. Based on RI values from Hakanson, the urban sediments showed moderate to considerable ecological risk. And the suburban sediments were in moderate ecological risk, except some high-risk samples. The majority of rural sediments revealed low ecological risk. Of these hazardous elements, Cd, Hg, and Pb contribute the largest proportion of the total ecological risk. It is evident that the urbanization level influences the distributions and contamination grades of PHEs for river sediments of the Changjiang Delta Region.
2

Analysis of correlation between the detection rate of Mycoplasma hyopneumoniae in slaughter pigs and season, climate change, and presence of lung lesions

86%
Li R. C., Hu Y. L., Ge M., Zhao D., Yang T. T., Qing R. K., Yu X. L.
Medycyna Weterynaryjna
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2019
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tom 75
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nr 03
The purpose of this study was to analyze the correlation of the rate of Mycoplasma hyopneumoniae (M. hyo) in slaughter pigs with season, climate change and enzootic pneumonia (EP) lesions. We collected 530 slaughter pig lungs with suspected lesions from two slaughterhouses in different seasons and weather conditions from November 2014 to March 2017 in Changsha Hunan Province, China. The EP lesions of these lungs were quantified, and a PCR analysis was used to detect M. hyo in samples of bronchoalveolar lavage fluid (BALF). Twenty percent, 10%, and 9% of the lung specimens were scored 1-5, 6-10, and ≥ 11, respectively. Additionally, we found that 36% of all BALF samples tested positive for M. hyo. Among the lung specimens collected in winter, 41% scored 1 or more, and 53% tested positive for M. hyo. With respect to seasons, the lung specimens collected in summer showed the least number of EP lesions and the lowest positive testing rate for M. hyo. Of these specimens, 27% scored 1 or more, and 22% tested positive for M. hyo. Additionally, low temperature and fast temperature change (during 10 days before sampling) were associated with a higher rate of M. hyo detection in BALF. There was a positive correlation between the lung EP lesion score and the detection rate of M. hyo in the BALF of slaughter pigs. In conclusion, lung EP lesion scoring in slaughter pigs is of referential value to the evaluation of the dynamics of M. hyo infection in a swine population. It is essential to control the spread of M. hyo by careful management of swine populations, and the prevention and control of M. hyo in fattening pigs is of great significance to the eradication of the disease.
3

Capsular types, LPS genotypes, and virulence-associated genes of Pasteurella multocida strains isolated from pigs

72%
Li R. C., Fang C., Luo W., Ge M., Hu Y. L., Zhao D., Qing R. K., Yu X. L.
Medycyna Weterynaryjna
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2020
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tom 76
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nr 08
Pasteurella multocida (P. multocida), an opportunistic zoonotic pathogen associated with high morbidity and mortality in livestock, shows significant temporal and geographical variation in its serotype distributions and phenotypic characteristics. The aim of this study was To investigate capsular types, lipopolysaccharide (LPS) genotypes, and virulence-associated genes of P. multocida strains isolated from pigs. A total of 801 samples (lungs, tonsils, nasal swabs) were collected from slaughterhouses and various regions of the Hunan province. P. multocida strains were isolated from various samples, classified, and virulence-associated genes were detected by polymerase chain reaction (PCR). 124 P. multocida strains were assigned to six groups based on both capsular type and LPS genotype, namely A: L3 (capsular type A and LPS genotype 3, 64/124); A: L6 (16/124); D: L6 (38/124); F: L3 (4/124); L3 (1/124) and 1 untypable strain. Of the 23 virulence-associated genes investigated in this study, 14 were highly expressed in 98% to 100% of the 124 strains. While tbpA was undetectable in any of the isolated strains, hsf-1, pfhA, tadD, toxA, pmHAS, hgbA, hgbB, and nanB showed differential distribution among the strain groups. Interestingly, pfhA (Mutation or inactivation of pfhA was reported to decrease the virulence of P. multocida) was found in 46% of group A: L3 strains and in 100% of group F: L3 strains, but not found in other groups. Further investigation is needed to determine whether strains in group A: L3show greater virulence than the A: L6 P. multocida strains.
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