The influenza of type A, here H1N1. The Mexican flu, also called pig flu, has been spreading. It is a viral infection of the human being of a new variant of influenza viruses. The virus particles are about 100 nm in size and contains RNA inside a viral envelope and belongs to the family Orthomyxoviridae. They cause symtoms in several body systems (fever, lethargy, cough, rhinits, vomiting, diarrhea).
The transmission of the A/H1N1-virus from pig to human to human happens via droplet infection. New virus-mutations may form.