No abstract

There has been emerging evidence that immunocompetent hosts can harbor Pneumocystis in their lungs. The purpose of this study was to determine the kinetics of Pneumocystis carinii f. sp. muris infection in adult immunocompetent mice and the host immune response to the organisms. To accomplish this, we exposed adult immunocompetent mice to SCID mice infected with P. carinii f. sp. muris by cohousing. We found that P. carinii f. sp. muris was detectable in the lungs of cohoused immunocompetent mice by PCR by 3 weeks after the beginning of cohousing. At about 4 weeks of cohousing, P. carinii f. sp. muris was readily detectable in the lungs of mice by microscopic techniques. Also at this time, P. carinii f. sp. muris-specific immunoglobulin G was found in the sera of the mice, and CD62low CD4- and CD8-positve T cells accumulated in the lungs. Shortly after this immune response, the P. carinii f. sp. muris organisms were cleared from the lungs. Adult mice cohoused for only 1 week also contained P. carinii f. sp. muris cysts detectable by silver staining at 5 and 6 weeks after the beginning of cohousing. We also found that the P. carinii f. sp. muris organisms grew to greater numbers in the lungs of BALB/c mice than in those of C57BL6 mice. This indicates that immunocompetent hosts develop a mild infection with P. carinii f. sp. muris which resolves in 5 to 6 weeks when there is a detectable immune response to the organism. Once an acquired immune response was initiated, the P. carinii f. sp. muris organisms were quickly eliminated without clinical signs of disease

Coccidioidomycosis is a deep mycotic infection endemic to Americas. Although it has also been reported to occur in non-endemic areas, it has rarely been reported in China. We reviewed the literature on case reports of coccidioidomycosis in China from 1958 to 2015. A total of 30 cases were reported from 11 provinces in China, and 23 (76.7%) cases were men, and 23 (76.7%) were in 30-60 years old. Twenty-seven (90.0%) cases were reported from southern China. Twenty-four (80.0%) cases had no history of exposure in endemic areas. Three cases were immunosuppressed, four cases had chronic disease, and 23 cases (76.7 %) were otherwise healthy. Twenty cases (66.6%) had related lung infection, six had skin infection, three cases were in lymph node, and one in the cornea, one in the bone and joint, and three had systemic disseminated infection. All of the 30 cases were diagnosis upon finding spherules in histological examination. Interestingly, 12 (40.0%) patients underwent surgery and removed the focus of infection because they were misdiagnosed or suspected of tumor or cancer previously. Fifteen cases (50.0%) were treated with amphotericin B, fluconazole, clotrimazole or ketoconazole. Diagnosis of coccidioidomycosis is complex, and misdiagnosis can occur easily in non-epidemic areas such as China.