About West Nile Virus

California faces greatest threat this year

Until 1999, the West Nile Virus was a tropical plague that North Americans only read about in newspapers.

The very first case of WNV is thought to have originated in 1937 in the West Nile region of Uganda, it later spread to other parts of Africa, Eastern Europe, West Asia, Middle Eastern countries. Five years ago, the first case was reported in New York. Since then, the WNV has since killed more than 560 Canadians and Americans.

The West Nile Virus affects North Americans mainly during summer and fall. WNV is carried by blood-feeding insects such as infected female mosquitoes (male mosquitoes don't suck blood) after she has fed on an infected bird. It is then passed from the infected mosquito to humans, birds and animals. A few cases of WNV have been transferred during pregnancy, breastfeeding, through blood transfusions and organ transplants.

Other facts:

• The risk of contracting WNV is very low - only 1% of mosquitoes are infected in areas where the West Nile Virus has been determined.
• Last year Colorado was had the most reported human cases of West Nile Virus, with 3,000 cases.
• California has been determined as the hotspot for WNV this season because of its numerous sites of standing, polluted water.
• West Nile Virus has proved lethal to horses, however there have been no cases found in dogs, cats, bats, squirrels, domestic rabbits or birds.
• A WNV vaccine is now available for horses, although there is none available to humans.