T.: H5N1 virus attachment to lower respiratory tract

Highly pathogenic avian influenza virus of the subtype H5N1 may cause infection of the lower respiratory tract (LRT) and severe pneumonia in humans (1). However, the cell types in the LRT to which the virus attaches are unknown for both humans and experimental animals. Although attachment is not the only factor required for virus replication, this information is important both to better understand the pathogenesis of H5N1 influenza and to assess the suitability of animal models. Therefore, we compared the pattern of H5N1 virus attachment to the LRT of humans and four animal species. Influenza viruses attach to host cells b

Proinflammatory Cytokine Responses in Extra-Respiratory Tissues During Severe Influenza

Severe influenza is often associated with disease manifestations outside the respiratory tract. While proinflammatory cytokines can be detected in the lungs and blood of infected patients, the role of extra-respiratory organs in the production of proinflammatory cytokines is unknown. Here, we show that both 2009 pandemic H1N1 influenza A (H1N1) virus and highly pathogenic avian influenza A (H5N1) virus induce expression of tumor necrosis factor α, interleukin-6, and interleukin-8 in the respiratory tract and central nervous system. In addition, H5N1 virus induced cytokines in the heart, pancreas, spleen, liver, and jejunum. Together, these data suggest that extra-respiratory tissues contribute to systemic cytokine responses, which may increase the severity of influenza

Detection of WNV in brains of mice infected with WNV-NY99.

<p>(A) The amount of WNV positive-sense RNA copies present in the brains of mice between days 3 and 6 post-infection with WNV-NY99. Mice were euthanized on day 3, 4, 5 and 6 post-infection and brains were collected and homogenized in DMEM for RNA isolation. (B) The amount of positive-sense RNA copies present in the brains of control mice and mice inoculated on days 3 and 5 post-infection. Brains were collected in RNA-later for RNA isolation using Trizol. Histopathology of the brains of 9-day old C57BL/6 mice infected with WNV-NY99. (C) Infected neurons in the brain of a mouse euthanized on day 3 p.i. (objective 20x). (D) Infected neurons in the cortex of a mouse euthanized on day 5 p.i. (objective 20x). Pictures are representative of the number of infected cells found in the brain for the majority of mice.</p