Electron Micrograph of Avian Influenza A

Electron Micrograph of Avian Influenza A

Electron Micrograph of Avian Influenza A

Colorized transmission electron micrograph of Avian influenza A H5N1 viruses (seen in gold) grown in MDCK cells (seen in green).

Avian influenza A viruses do not usually infect humans; however, several instances of human infections and outbreaks have been reported since 1997. When such infections occur, public health authorities monitor these situations closely.