Location, Location, Location: Five Facts about Tissue Tropism and Pathogenesis

[...]seasonal influenza viruses mainly infect the upper respiratory tract, while pandemic influenza as well as some highly pathogenic avian influenza viruses (e.g., H5N1) have increased ability to infect the lower respiratory tract [6]. [...]the increasing ease of genetic manipulation, including CRISPR/Cas9 technology, facilitates the necessary validation of the factors identified in these large-scale studies. [...]fine-scale differences in host tissue chemistry, metabolism, waste production, and local immune responses are still being identified. [...]while we usually know the ultimate tissue niche of a specific pathogen, we often do not understand the paths used to reach that location, as evidenced by the controversy surrounding the timing of brain penetration in T. brucei infection [4].