Pathological Study Of Coxiella Burnetii Infection In BALB/c Mice

Q fever is a worldwide zoonosis caused by coxiella buraetii.Light microscopy, electron microscopy,immunohistochemical staining, in situ hybridization,and PCR were performed to study the pathological changes of mice inoculated with Coxiella burnetii.ResuIts:1.The mice inoculated with Coxiella burnetii intrana- sally developed interstitial pneumonia,while the primary pathological changes of mice inoculated intraperitoneally are granulomas in spleen and liver.2.The pathological changes became more severe followed the dosage increasing.3.Coxiella burnetii can be detected in spleen and liver at day 2 after inoculation.the lesion became more and more serious from day 2 to day 12.The characteristic changes were observed at day 7,and recovered at day 14. 4.The reticuloendothelial system are main target of Coxiella burnetii.The pathogen was detected in cytoplasm of monocyte -macrophages of spleen, liver, lung, and endothelioid cells of blood vessel. 5. Coxiella burnetii can be found in macrophages lysosomes by electron microscopy. Most of them are round or rod, and polymorphic shape can also be observed in different size. 6.The expression of cytokines including IL-10 TNF IFN- r in spleen increased after infection.Conclusion: l.Coxiella burnetii can induce pathological changes in mice. The lesion resembled to those in Q fever patients. The animal model is suitable for Q fever research. 2.The mice developed interstitial pneumonia and granulomas in spleen and liver separately by inoculating with Coxiella burnetii intranasally or intraperitoneally. 3.The pathological changes correlated with injecting dosage. 4.The typical changes happened at day 7 in intraperitoneally inoculating group. 5.The reticuloendothelial system are main target of Coxiella burnetii. 6.Cytokines including IL-10 TNF IFN-r play an important role in the pathogenesis of Q fever.