West Nile virus other emerging threats to public health

West Nile virus is an icosahedral, spherical (50 nm in diameter) arbovirus of the Flaviviridae family. Its genome contains single-stranded RNA with positive polarity (ssRNA+). Virions are build of three structural proteins: envelope glycoprotein E, core protein C and membrane protein prM. Apart from them, the virus genome codes for seven non-structural proteins: NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5. Transmission vectors of WNV are mosquitoes of the Culex pipiens species and other blood-eating insects. Its main reservoir are migrating birds, whereas humans and other mammals are its occasional host. West Nile Virus shows high neurotropism and is the cause of morbidity and mortality in different animals and humans. During the last ten years, it has been identified in Asia, Africa, Europe and both Americas. WNV was found in Poland too. This paper considers also the new haemorragic fever and SARS.