The mosquito may seem like a fairly harmless insect; however, it can be extremely deadly when it is a carrier of the West Nile Virus (WNV). The West Nile Virus is a deadly microscopic organism that has recently spread throughout the world. This virus is unique in that it can infect multiple species. The West Nile virus is not only able to infect humans, but animals like birds and horses. It is transmitted throughout the different species through mosquito bites. Mosquitoes that are infected with the disease bite organisms, which then transmit the disease to them. The West Nile virus can have major negative impacts on the biodiversity of ecosystems and on the well being of society. The West Nile virus was first discovered in the African country of Uganda in 1937. Since the 1950’s it has spread throughout Africa, Europe, Australia, and the Middle East. In 1999 scientists discovered the virus for the first time in the Western hemisphere when it killed hundreds of birds in the northeast United States. The disease has since spread to horses and humans. The Culex tarsalis mosquito is the most common carrier of the disease. It causes flu-like symptoms, especially fever and headaches. These symptoms usually appear within 3 to 15 days of contracting the disease. Since 1999, 23,000 Americans have contracted the disease and 962 have died; 3 to 15 percent of people who contract the virus die from it. The West Nile virus primarily affects birds, especially blue jays and crows. The decline in population of these birds has had severe effects on the biodiversity of ecosystems. Almost all crows that contract the disease die because of it. The crow population has decreased by 45% since 1999. In the case of the blue jay its foremost role in ecosystems is to alert different bird species when a predator such as a hawk or an eagle is approaching. This helps other bird species such as sparrows and warblers escape predators. With the decline of blue jays