病毒感染检查概要.ppt

1、病毒感染检查approaches to the diagnosis of viral infection(1) There are two major approaches to the diagnosis of viral infection: virologic and serologic. The virologic approach includes (1) isolation of infectious virus in cell culture or in laboratory animals, (2) detection of viral antigen by immunolog

2、ic methods such as immunofluorescence assay (IFA) or enzyme immunoassay (EIA), (3) identification of viral particles by electron microscopy (EM), and (4) detection of viral nucleic acid. approaches to the diagnosis of viral infection(2) The serologic approach includes (1)demonstration of a fourfold

3、or greater rise in antiviral antibody using acute and convalescent sera and a variety of methods that measure predominantly immunoglobulin (Ig) antibody and (2)demonstration of virus-specific IgM antibody in a single late acute or recovery phase serum.标本处理 必须经滤过除菌，标本需迅速冷藏、运送。 Optimal Temperature For

4、 Storage And Transport Of Specimenfor viral culture and antigen detection is 4 (refrigerator or wet ice temperature). Freezing at -20 (ordinary freezer temperature) destroys or significantly reduces infectivity of virtually all viruses. If specimens must be stored for longer than 3 to 4 days, an ult

5、ra-low temperature freezer(-70 )should be used, and specimen transported to the virology laboratory on ice.细胞系选择 与 细胞病变特征 1.Several Different Types Of Cells： Because not all culturable viruses will grow in a single cell line, several different types of cells are required. 2.病毒分离培养后，根据细胞病变特征确定病毒的种， C

6、ytopathic Effect (CPE) ： Many viruses will demonstrate a cytopathic effect (CPE) within a few days, whereas some may take as long as a week or two . Some viruses will do not cause typical CPE and are identified by the adsorption of red blood cells to the surface of virus-infected cells in the cultur

7、e. Confirmation Of a Specific Virus : 对已分离的病毒用已知参考血清作中和试验、补体结合试验、血凝抑制试验鉴定 Confirmation of a specific virus serotype or of a virus (e.g.HSV-2, influenza A H3N2, echovirus11)requires use of immunologic methods with antibody of known specificity. In recent years, fluorescence or peroxidase-conjugated m

8、onoclonal antibodies(MABs)have become available commercially to detect viral antigen in cell. 早期诊断技术 核酸杂交技术、 1、 Solid phase 2、 Liquid-phase 3、 In Situ HybridizationIn PCR技术Diagnosis of viral infections The primary diagnostic technique for most viral infections is the isolation of the virus in cell c

9、ulture. Serologic techniques may also be useful, especially if the virus was isolated from a nonsterile site. In some instances, serologic diagnoses is the only practical approach in a clinical laboratory. Direct detection of antigen in body fluids or tissues has also been effective for some viruses

10、. The list of agents for which direct detection of antigen is useful will undoubtedly continue to expand. The compare of the advantages and disadvantages of each of these approaches: Culture:Time:Days to weeksAdvantages:Specificity and sensitivity maximum;isolate available for characterizationDisadv

11、antages:Cell culture facilities needed;time for diagnosis may be long Direct detection:Time:Hours to 1 dayAdvantages:Speed of diagnosis;used for viruses difficult to cultureDisadvantages:False-positives and negatives;hard to batch tests Serology:Time:WeeksAdvantages:Assessment of immunity or response to virus isolated from nonsterile site; used for viruses difficult to cultureDisadvantages:Potential cross-reaction;need for acute and convalescent specimens