Agar Gel Immunodiffusion Assay to Detect Antibodies to Type A Influenza Virus.

The agar gel immunodiffusion (AGID) test is used to detect antibodies to Type A influenza group-specific antigens, i.e., the nucleoprotein (NP) and matrix (M) proteins. Therefore, this test will detect antibodies to all influenza A virus subtypes. AGID is commonly used to screen poultry flocks for avian influenza virus infection. The AGID is a simple and economical serological test. All serological testing has its advantages and disadvantages, which should be considered before choosing the optimal test for the laboratory needs. Each laboratory must evaluate the laboratory's resources, the volume of testing, the goal of testing, how the test results are used, and what types of samples are being tested in order to select the optimal test.

Agar gel immunodiffusion assay to detect antibodies to Type A influenza virus.

The agar gel immunodiffusion (AGID) test is used to detect antibodies to Type A influenza group-specific antigens, i.e., the ribonucleoprotein (RNP) and matrix (M) proteins. Therefore, this test will detect antibodies to all influenza A virus subtypes. AGID is commonly used to screen poultry flocks for avian influenza virus infection. The AGID is a simple and economical serological test. All serological testing has its advantages and disadvantages which should be considered before choosing the optimal test for the laboratory needs. Each laboratory must evaluate the laboratory's resources, the volume of testing, the goal of testing, how the test results are used and what types of samples are being tested in order to select the optimal test.

Identification of mosquito bloodmeal source by terminal restriction fragment length polymorphism profile analysis of the cytochrome B gene.

Previous studies have shown that polymerase chain reaction (PCR) heteroduplex analysis (HDA) of the cytochrome B (cytb) gene is useful in identifying mosquito bloodmeals derived from avian hosts. However, interpretation of PCR-HDA gels is performed visually, which can make it difficult to analyze large numbers of specimens and to compare results between laboratories. We investigated the utility of a terminal restriction fragment length polymorphism (T-RFLP) assay to analyze cytb PCR products. PCR was performed on 123 blood or tissue samples from 55 avian, 13 mammalian, and one amphibian species by using end-labeled primers to amplify a 358-bp segment of cytb. Each PCR product was sequenced to determine predicted terminal restriction fragment (TRF) profiles. Additionally, experimental TRFs were determined by sizing fragments from restriction endonuclease digests with capillary electrophoresis. A Web-based searchable database was created to compare unknown mosquito bloodmeal TRF profiles against sequence-predicted and experimentally derived terminal fragment lengths of known vertebrates. The predictive value of experimental profiles was found to be accurate to the species level for 67 of 69 species (97%). Fifty-nine field-collected mosquitoes were tested to determine the bloodmeal source using the T-RFLP method. The bloodmeal source from 50 of these mosquitoes was identified by comparing the TRF profile of the unknown source against the cytochrome B database. The bloodmeal source from the remaining nine mosquitoes was not identified as no known profile matched the experimentally derived profile. T-RFLP analysis is a highly reproducible technique and the searchable TRF database is continually being expanded to include additional species from diverse geographic areas.