West Nile Virus
This virus is transmitted by various species of mosquitoes and can infect both human and animals. The virus was first found in a woman in the West Nile sub-region of the East African nation of Uganda in 1937. There was an outbreak of the virus in Romania in 1996 that saw a high number of cases with neuroinvasive disease and caused the deaths of 40 people. The virus became well-known when it spread to the United States in 1999.