Dispersion of particulate matter around poultry farms, based on field measurements of endotoxin concentrations in air samples and OPS-ST particulate matter modeling.

<p>A) Maps illustrating the air sampling locations together with the atmospheric dispersion of particulate matter (relative to the source) that was modeled using meteorological data corresponding with the day and timeframe (10:00AM—16:00PM) of air sampling. B) Scatterplot of modeled dispersion and measured endotoxin concentration. Qualitative results of influenza virus RNA and turkey cell DNA detection are depicted as well.</p

Combined dataset depicting the farms, air-sample type, and location relative to the barn, and corresponding laboratory results including influenza virus RT-PCR detection, turkey COI RT-PCR detection, endotoxin quantification, and modeled relative particulate matter concentrations of all GSP and MD8-AirPort filters assayed.

<p>nd) not determined</p><p>*) Below detection limit</p><p>#) outside plume</p><p>Combined dataset depicting the farms, air-sample type, and location relative to the barn, and corresponding laboratory results including influenza virus RT-PCR detection, turkey COI RT-PCR detection, endotoxin quantification, and modeled relative particulate matter concentrations of all GSP and MD8-AirPort filters assayed.</p

Correlations of antibody responses to group 1 influenza viruses.

<p>Results are given for age groups 5-44 years (above the diagonal) and 45+ years (below the diagonal). Black dots: pre-pandemic survey; red dots: post-pandemic survey. In each panel, Kendall’s tau is given for the pre- and post-pandemics surveys (black and red). Notice the strong positive correlation between H2N2 and H9N2 antibody titers in persons up to 45 years, i.e. persons who are unlikely to have experienced a natural H2N2 infection. Positive antibody titers to H2N2 and H9N2 are found almost exclusively in persons with positive A/2009 (H1N1) response, suggesting that A/2009 (H1N1) infection yields a response that is cross-reactive with both H2N2 and H9N2.</p

Antigens included in the microarray.

<p>Antigens included in the microarray.</p

Endotoxin concentrations in air samples outside poultry barns are depicted in relation to the distance from the poultry barn, illustrating a reduction of airborne endotoxin with increasing distance from the source.

<p>Endotoxin concentrations in air samples outside poultry barns are depicted in relation to the distance from the poultry barn, illustrating a reduction of airborne endotoxin with increasing distance from the source.</p

Age-specific antibody titers to group 2 influenza A viruses.

<p>Red dots indicate an H7N7 titer ≥40. Seroprevalence to H3N2 viruses reaches 100% in most age strata. Solid and dotted lines show the mean weighted antibody concentrations and associated 95% confidence ranges, estimated with a generalized additive model. For H7N7, solid and dotted lines show interval population-weighted seroprevalence estimates and associated 95% confidence bounds (right axis). Antigens (HA1) included are from viruses A/Aichi/2/1968 (H3N2), A/Wyoming/2003 (H3N2), A/Brisbane/10/2007 (H3N2), and A/Ck/Netherlands/2003 (H7N7).</p

Age-specific antibody titers to group 1 influenza A viruses.

<p>Pre- and post-pandemic samples are represented by triangles and circles, respectively. Red dots indicate that H9N2 titer was ≥40. Solid and dotted lines show weighted seroprevalence estimates and associated 95% confidence ranges, estimated with a logistic generalized additive model (right axis). Seroprevalence estimates are weighted by their contribution to the population census [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181093#pone.0181093.ref008" target="_blank">8</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181093#pone.0181093.ref043" target="_blank">43</a>]. For clarity, only pooled pre- and post-pandemic prevalence estimates are presented. Antigens (HA1) included are from viruses A/South Carolina/1/1918 (H1N1), A/Canada/720/2005 (H2N2) (1957-like H2N2), A/Brisbane/59/2007 (H1N1), A/California/6/2009 (H1N1), A/Guinea fowl/Hong Kong/WF/10/1999 (H9N2).</p

Correlations of antibody responses to avian influenza A viruses.

<p>Results are given for age groups 5-44 years (above the diagonal) and 45+ years (below the diagonal). Black dots: pre-pandemic survey; red dots: post-pandemic survey. In each panel, Kendall’s tau is given for the pre- and post-pandemics surveys (black and red). Notice that all persons with positive H7N7 response also have a positive H9N2 response. Antigens included are from viruses A/Vietnam/1194/2004 (H5N1), A/Chicken/Netherlands/1/2003 (H7N7), and A/Guinea fowl/Hong Kong/WF10/1999 (H9N2).</p

Discrimination of Influenza Infection (A/2009 H1N1) from Prior Exposure by Antibody Protein Microarray Analysis

<div><p>Reliable discrimination of recent influenza A infection from previous exposure using hemagglutination inhibition (HI) or virus neutralization tests is currently not feasible. This is due to low sensitivity of the tests and the interference of antibody responses generated by previous infections. Here we investigate the diagnostic characteristics of a newly developed antibody (HA1) protein microarray using data from cross-sectional serological studies carried out before and after the pandemic of 2009. The data are analysed by mixture models, providing a probabilistic classification of sera (susceptible, prior-exposed, recently infected). Estimated sensitivity and specificity for identifying A/2009 infections are low using HI (66% and 51%), and high when using A/2009 microarray data alone or together with A/1918 microarray data (96% and 95%). As a heuristic, a high A/2009 to A/1918 antibody ratio (>1.05) is indicative of recent infection, while a low ratio is indicative of a pre-existing response, even if the A/2009 titer is high. We conclude that highly sensitive and specific classification of individual sera is possible using the protein microarray, thereby enabling precise estimation of age-specific infection attack rates in the population even if sample sizes are small.</p></div

Standardised hemagglutination inhibition titers as a function of A/2009 microarray titers.

<p>Data are stratified by study and age group (5–9, 10–19, 20–44, and 45–65 years). The bottom left corner in each panel shows the number of samples that tested negative in both assays. The top right corner shows Kendall's tau, a nonparametric correlation coefficient.</p