Abstract:

【Objective】 The main purpose of the current study was to construct a Balb/c mouse model of N. caninum infection in both acute phase and subacute phase, and to study the development process of N. caninum in mouse. 【Method】 In this research, Balb/c mice were divided into two groups, each group was inoculated with 8×106 tachyzotie /mice and 5×105 tachyzotie /mice, respectively. Mice were euthanatized at different time points. Tissues of heart, liver, lung, brain and muscle were used for pathological, immuohistochemical and microbiological examination. 【Result】 Both of the two groups were characteristed with vacuolar degeneration of the hepatocyte, hemorrhage in the lung and other visceras, nonsuppurative inflammation and necrosis in the brain. Cysts could be found in the brain 16 d after inoculation, and no cyst was observed in other tissues. The result of PCR revealed that N. caninum specific gene Nc-5 could be detected in lung and heart 12 h after inoculation, 8 d in brain. Nc-5 gene still could be detected in liver, lung and brain 25 d post infection. A tissue predilection to liver, lung and brain was found according to the results of histopathological examination. And male mouse showed more susceptivity to N. caninum than female did. 【Conclusion】 Acute and subacute N. caninum infection models were successfully built up in BALB/c mice. The spread of tachyzoites among the tissues was traced in the mouse model, and the dynamic process of N. caninum infection in BALB/c mice was discovered.

Key words: neosporosis, Balb/c mice, animal model, development process