BACKGROUND We designed a seroprevalence study using multiple testing assays and population sources to estimate the community seroprevalence of pH1N1/09 and risk factors for infection before the outbreak was recognized and throughout the pandemic to the end of 2009/10 influenza season. METHODS Residual serum specimens from five time points (between 01/2009 and 05/2010) and samples from two tim...

Three serological procedures, the agar-gel precipitin inhibition, the complement fixation, and the indirect hemagglutination tests, were used to detect and measure antibody to Yersinia pestis in the sera from 383 individuals. Although all three tests were useful in detecting plague antibody, the most reliable and sensitive test procedure was indirect hemagglutination.

Goose erythrocytes preserved with glutaraldehyde were compared with fresh cells in hemagglutination and hemagglutination-inhibition tests for arbovirus antigens and antibodies. The glutaraldehyde-fixed cells were as sensitive and specific as theresh erythrocytes and were stable at 4 degrees C for 6 months.

Five erythrocyte species (horse, goose, chicken, guinea pig, and human) were used to agglutinate avian influenza H5N1 viruses by hemagglutination assay and to detect specific antibody by hemagglutination inhibition test. We found that goose erythrocytes confer a greater advantage over other erythrocyte species in both assays.

3. Pushpa V, Sheila M. Dengue hemorrhagic fever in Madras, 1989. (Unpub lished data). 4. darker DH, Casal J. Technique for hemagglutination and hemagglutination inhibition with nrthropod borne viruses. Am J Trop Med Hyg 1958, 7: 561-567. 5. Manchni G, Carbonara AO, Hereonara JF. Immunochemical quantitation of antigens by single radial immune diffusion. Int J Immunochemical 1965, 2: 235-254.

A new diluent (ADGP) for the rubella virus hemagglutination (HA) and hemagglutination-inhibition (HI) tests is described. It was found that the HA and HI titers and the erythrocyte agglutination pattern were improved in ADGP compared to previously described diluents. The influence of the components of ADGP and of various test conditions on optimal HA and HI results were examined.

Like enteroviruses, hepatitis A virus (HAV) hemagglutinated various species of erythrocytes under similar conditions. HAV-specific antibodies in both acute- and convalescent-phase sera were found to inhibit hemagglutination. The HAV hemagglutination inhibition test can be used for diagnosis, epidemiological surveillance, and vaccine assessment.

Visna virus particles inhibit influenza virus hemagglutination in an assay for neuraminic acid-containing viruses. Pretreatment of visna virus with neuraminidase abolished hemagglutination inhibition activity but did not significantly affect attachment, infectivity, or virus-induced cell fusion in sheep choroid plexus cell monolayers.

BACKGROUND The 2009 H1N1 influenza pandemic initially affected Mexico from April 2009 to July 2010. By August 2010, a fourth of the population had received the monovalent vaccine against the pandemic virus (A(H1N1)pdm09). To assess the proportion of the Mexican population who remained potentially susceptible to infection throughout the summer of 2010, we estimated the population seroprevalence ...