Detection of Toxoplasma gondii in chicken and soil of chicken farms in Nanjing region, China.

BACKGROUND: Soil is increasingly recognized as an important source in the transmission of Toxoplasma gondii (T. gondii). The aim of this study was to investigate the presence of T. gondii in the soil and to grasp the relationships between the contamination of soil and chicken infections. METHODS: PCR method based on T. gondii-conserved gene internal transcribed spacer 1 (ITS-1) as target gene and ELISA method (sGRA8-ELISA) using the recombinant protein of shortened GRA8 gene of T. gondii as antigen were developed and applied. From April 2013 to March 2014, a total of 700 soil samples were collected at various sites located in thirty farms categorized as free range farm and scale farm in Nanjing, Jiangsu, China, in different seasons. Additionally, a total of 350 sera of chickens were collected from free range farms to determine the presence of antibodies against T. gondii using sGRA8-ELISA. RESULTS: The serological results showed that, antibodies were found in 194 of 250 (67.14%) samples from farms with T. gondii positive in soil and 41 of 100 samples from farms with T. gondii negative in soil (41.00%) (P < 0.01). The PCR detection of soil samples showed that, 7 (2.0%) of 350 samples collected from feeding zone in free range farms were found positive of T. gondii, whereas no sample was positive in scale farms. In the seasonal detections, T. gondii was found in 6 (3.33%) samples collected in autumn and 1 (0.56%) collected in winter. CONCLUSIONS: The results indicated that the contamination of T. gondii in soil in the free range farms was higher than that in the scale farms and seroprevalence of T. gondii in chickens in the farm with soil contamination was higher than that with no soil contamination. The soil contamination might be an effective indicator of T. gondii infection in chickens.

Haemonchus contortus excretory and secretory proteins (HcESPs) suppress functions of goat PBMCs in vitro.

Excretory and secretory products (ESPs) of nematode contain various proteins which are capable of inducing the instigation or depression of the host immune response and are involved in the pathogenesis of the worms. In the present study, Haemonchus contortus excretory and secretory products (HcESPs) were collected from the adult worms. Binding of HcESPs to goat peripheral blood mononuclear cells (PBMCs) was confirmed by immune-fluorescence assay. Effects of the HcESPs on cytokine production, cell proliferation, cell migration and nitric oxide (NO) production of PBMCs were checked by co-incubation of HcESPs with goat PBMCs. The results indicated that the production of IL-4 and IFN-γ were significantly decreased by HcESPs in dose dependent manner. On the contrary, the production of IL-10 and IL-17 were increased. Cell migration was significantly enhanced by HcESPs, whereas, HcESPs treatment significantly suppressed the cell proliferation and NO production. These results indicated that the HcESPs played important suppressive regulatory roles on PBMCs and provided highlights to the understanding of the host-parasite interactions.

Pathogenicity of Five Strains of Toxoplasma gondii from Different Animals to Chickens.

Toxoplasma gondii is a protozoan parasite with a broad range of intermediate hosts. Chickens as important food-producing animals can also serve as intermediate hosts. To date, experimental studies on the pathogenicity of T. gondii in broiler chickens were rarely reported. The objective of the present study was to compare the pathogenicity of 5 different T. gondii strains (RH, CN, JS, CAT2, and CAT3) from various host species origin in 10-day-old chickens. Each group of chickens was infected intraperitoneally with 5×10(8), 1×10(8), 1×10(7), and 1×10(6) tachyzoites of the 5 strains, respectively. The negative control group was mockly inoculated with PBS alone. After infection, clinical symptoms and rectal temperatures of all the chickens were checked daily. Dead chickens during acute phage of the infection were checked for T. gondii tachyzoites by microscope, while living cases were checked for T. gondii infection at day 53 post-inoculation (PI) by PCR method. Histopathological sections were used to observe the pathological changes in the dead chickens and the living animals at day 53 PI. No significant differences were found in survival periods, histopathological findings, and clinical symptoms among the chickens infected with the RH, CN, CAT2, and CAT3 strains. Histopathological findings and clinical symptoms of the JS (chicken origin) group were similar to the others. However, average survival times of infected chickens of the JS group inoculated with 5×10(8) and 1×10(8) tachyzoites were 30.0 and 188.4 hr, respectively, significantly shorter than those of the other 4 mammalian isolates. Chickens exposed to 10(8) of T. gondii tachyzoites and higher showed acute signs of toxoplasmosis, and the lesions were relatively more severe than those exposed to lower doses. The results indicated that the pathogenicity of JS strain was comparatively stronger to the chicken, and the pathogenicity was dose-dependent.

[Assay of three kinds of aluminum fractions (Al(a), Al(b) and Al(c)) in polynuclear aluminum solutions by Al-Ferron timed spectrophotometry and demarcation of their time limits].

Al-Ferron timed spectrophotometry assay is a basic method in the study on the formation of polynuclear hydroxyl aluminum species and their transformation laws in aqueous systems. In actual working process, this methodology has some dogmatism and arbitrariness in the time limits demarcation of the three kinds of aluminum fractions (Al(a), Al(b) and Al(c)) in polynuclear aluminum solutions, which makes this kind of classification rougher, and the experimental results non-reproducible. The reason for this difference is that the specific species within Al(a), Al(b) and Al(c) have different reaction mechanism and dynamics, and that specific species of Al(b) having different OH/Al ratios have different reaction rates with ferron. In this paper, the ExpAssoc distribution was applied to quantitatively fit the Al-Ferron reaction dynamics curve, and the extrapolation method was used to survey the 1 min measured value [Al(a)] of monomeric Al, which is hard to obtain in manual manipulation. The time demarcation between Al(b) and Al(c) should reach the point of the experimental data curve up to horizontal platform. The microwave-radiated technology was used to fast assay the total aluminum concentration [Al(T)]. With these methods, the contents of monomeric Al(a), polynuclear Al(b) and gel Al(c) can be conveniently and quantitatively measured. It offers a novel method for surmounting the arbitrariness in the measurement of the three kinds of aluminum fractions and the repetitive calculation of Al(a) and Al(b).