关键词: 刚地弓形虫, 比格犬, 发病模型

Abstract:

Object To establish a infection dog model with RH strain of Toxoplasma gondii. Method Three specific pathogen-free 76 day-old Beagles were intraperitoneal injected with 1. 5 × 107 tachyzoites of Toxoplasma gondii. The dogs had been growing in positive pressure isolators under barrier environment and fed with artificial milk. The experiment was carried out under negative pressure barrier environment. After inoculation, anal temperatures, oral and anal swabs were collected twice daily to detect B1 gene of T. gondii by PCR. At 8 days post inoculation ( dpi ) all animals were euthanized, and nucleotide copies of Rep529 nt at various tissues were quantified by real-time PCR method. Histopathology and immunohistochemical stains changes were observed. Result The result showed that the three dogs had fever and diarrhea at 4 dpi-5 dpi; much ascites was appeared when the abdomens were opened; B1 gene of T. gondii was detected in oral or anal swabs at 2 dpi - 6 dpi by a routine PCR method, and the PCR result positive rate of the anal swabs was higher than that of the oral swabs totally, there was obvious inflammatory reaction in the liver tissue in histopathological observation with HE stain. Among all the detected tissues sampled on autopsy using the Taqman real-time PCR, the copy number of the Rep529 nt was high in cecum and liver. Conclusion The infectious experiment shows that there merely causes a mild infection model on SPF Beagles when inoculated with RH strain of T. gondii, with transient increase of body temperature and diarrhea, liver degeneration and necrosis.

Key words: Toxoplasma gondii, laboratory beagles, disease model