RESUMEN
The information on Chlamydia infection in cattle is limited in Shanxi Province, north China. This study aimed to investigate the seroprevalence and risk factors of Chlamydia and Chlamydia abortus infection in cattle in Shanxi Province. In November 2020, a large-scale investigation of Chlamydia seroprevalence was conducted on 981 cattle serum samples collected from 40 cattle farms in 11 cities of Shanxi Province. The seroprevalence of Chlamydia and C. abortus was examined by indirect hemagglutination assay (IHA) and enzyme-linked immunosorbent assay (ELISA), respectively. The seroprevalence of Chlamydia and C. abortus was 52.29% (513/981) and 2.96% (29/981), respectively, in cattle in Shanxi Province. Location was identified as a risk factor for Chlamydia and C. abortus infection (p < 0.05). Under different management patterns, the seroprevalence of Chlamydia and C. abortus in large-scale animal farming companies was higher than that in household animal farms and animal farming cooperatives, and only the seroprevalence of Chlamydia was significantly different in different management patterns (p < 0.01). The results showed that there was higher seroprevalence of Chlamydia in cattle in Shanxi Province, while C. abortus was not the dominant species. This study provided baseline information on Chlamydia infection in cattle in Shanxi Province, which constitutes valuable data for monitoring livestock health and preventing potential zoonoses.
RESUMEN
Neospora caninum is an obligate intracellular parasitic protozoan that can cause abortions in cattle and pose considerable economic losses to the cattle industry. As a major livestock province, little is known of N. caninum infection in cattle in Shanxi Province, north China. In order to investigate the seroprevalence of N. caninum in cattle in Shanxi Province, 978 cattle serum samples were collected from 11 cities in three representative geographical locations in Shanxi Province, and the N. caninum-specific IgG antibodies were examined using an indirect enzyme linked immunosorbent assay (ELISA) kit commercially available. The results showed that 133 of the 978 examined cattle serum samples (13.60%, 95% CI = 11.45-15.75) were positive for N. caninum antibodies, and the seroprevalence in different cities ranged from 0 to 78.89%. The geographical location and management mode were the risk factors associated with N. caninum infection in cattle herds in Shanxi Province. Cattle in Northern and Central Shanxi Province as well as cattle whose management mode is that of large-scale cattle farming companies are more susceptible to N. caninum infection. This was the first large-scale survey of N. caninum seroprevalence and assessment of associated risk factors in cattle in Shanxi Province, which provided baseline information for the prevention and control of N. caninum infection in cattle in Shanxi Province, north China.
RESUMEN
Chlamydia, an obligate intracellular bacterium, can cause chlamydiosis in humans and animals worldwide and also leads to serious economic losses to the sheep industry. However, the information on Chlamydia infection in sheep was limited in Shanxi Province, northern China. In the present study, a total of 984 serum samples of sheep were collected from 11 regions in Shanxi Province, northern China in the autumn of 2020. The antibodies against Chlamydia and Chlamydia abortus were examined by the indirect hemagglutination assay (IHA) and indirect enzyme-linked immunosorbent assay (ELISA), respectively. The result showed that 351 (35.67%, 95% CI 32.68-38.66) of 984 serum samples were positive for Chlamydia, and the seroprevalence ranged from 6.67% to 70.79% among the different regions. In addition, antibodies to C. abortus infection were detected in 78 (7.93%, 95% CI 6.24-9.61) of 984 serum samples, and the seroprevalence ranged from 6.24% to 14.81% among the different regions. This is the first report on the seroprevalence of Chlamydia and C. abortus in sheep in Shanxi province, northern China. The findings provide baseline information for preventing and controlling Chlamydia infection in sheep in Shanxi Province, China.
RESUMEN
Taihang Mountain region is the recharge area for groundwater in the North China Plain (NCP). In recent years, the elevated nitrate concentration in the groundwater in the Taihang Mountain has often been associated with the increased area of farmland and the excessive application of nitrogen. Thus, it is significant to study the soil nitrogen leaching process in typical farmland. In this study, the root zone water quality model (RZWQM) was used to simulate the nitrate nitrogen leaching of winter wheat/summer maize rotation systems in the Hilly Ecosystem Experimental Station in Taihang Mountain. The results showed that during the 2015-2016 winter wheat/summer maize season, the nitrate nitrogen from the soil leaching occurred mainly in the summer maize season (rainy season), with the nitrate nitrogen leaching amount reaching 59.9 kg·hm-2, while the nitrate nitrogen leaching amount during the winter wheat season was only 2.12 kg·hm-2. The soil nitrate nitrogen leaching condition was simulated using the RZWQM model for different nitrogen contents and years with different rainfall. Significant linear correlations were observed between nitrogen use and nitrate leaching in winter wheat/summer maize rotation systems. In summary, the results showed that the nitrate nitrogen leaching values were 10.5, 59.9, and 136.5 kg·hm-2 for nitrogen fertilizer applications of 0, 300, and 450 kg·hm-2, respectively, during extreme precipitation in a wet year (2015). The value of nitrate nitrogen leaching in the maize season of 2013 (dry year), 2015 (normal year), and 2016 (wet year) accounted for 9%, 10%, and 20% for the 300 kg·hm-2 of nitrogen fertilizer applied, respectively. However, the value of nitrate nitrogen leaching in the maize season of 2013 (dry year), 2015 (normal year), and 2016 (wet year) accounted for 11%, 17% and 30% of the 450 kg·hm-2 of nitrogen fertilizer applied. These results show that extreme precipitation events not only greatly recharge the groundwater, but also increase the leaching of accumulated nitrate nitrogen and potential nitrate contamination in the groundwater.
