Dutch researchers have identified cell groups within the respiratory tract according to susceptibility to human viruses and avian viruses, states the October issue of the American Journal of Pathology.

Differences in cellular expression of target molecules correspond to host specificity of influenza viruses. They also define which organs or tissues are infected within the host. For example, highly pathogenic H5N1 avian influenza virus targets cells deep within the lower respiratory tract. Human influenza virus, however, is believed to target upper respiratory tract cells, including the trachea.

Using a technique called virus histochemistry, a team led by Thijs Kuiken, PhD, Erasmus MC, Rotterdam, Netherlands, found that human viruses attached strongly to both the trachea and bronchi, but virus binding to the bronchioles and alveoli, which are deeper within the lung, was less common in comparison. Conversely, avian viral attachment was uncommon in the trachea and more frequent in the bronchioles and alveoli.

The findings are consistent with the differences in human disease presentation, with human influenza causing tracheobronchitis and highly pathogenic avian influenza causing severe pneumonia.

To read the abstract, click here.