West Nile Virus in the US

Photo by Thomas Kent

Crop-dusting planes are spraying the city of Dallas with insecticide in an effort to kill mosquitoes. It's been a bumper year for mosquitoes, there and elsewhere in the US, and reports of West Nile virus have risen accordingly. 

West Nile aerial attack creates controversy in virus-stricken Dallas | The Lookout - Yahoo! News
"43 states have reported West Nile virus infections in people, birds or mosquitoes this year. Twenty-six people have died and nearly 700 have gotten sick.

"The 693 cases reported thus far in 2012 is the highest number of West Nile virus disease cases reported to CDC through the second week in August since West Nile virus was first detected in the United States in 1999," the CDC said in a statement."

The virus produces two illnesses. The first is a mild form with flu-like symptoms called West Nile fever. The second, West Nile encephalitis, occurs when the virus invades the central nervous system. Encephalitis means inflammation of the brain. It can cause such symptoms as headache, fever, stiff neck, tremors, stupor, disorientation, and paralysis. It is sometimes fatal. 

In the terror-obsessed US of the 21st century, the virus has become notorious out of all proportion to its actual danger. The fever afflicts only about 20 percent of those who contract the virus; of that 20 percent, two-thirds of one percent develop encephalitis. Most of those recover. Deaths occur mostly in the elderly. The reservoir for the virus is birds. In the US, robins and crows are among the most commonly infected birds. The virus is transmitted to people by mosquitoes of the genus Culex, especially Culex pipiens.

Photo: A member of the genus Culex, probably C. pipiens. Note that the mosquito is itself infested with parasites. Virtually any animal can host its own brand of mites, maggots, or wasp larvae. Photographer Thomas Kent's Flickr page features many startling and beautiful macro-discoveries. 


  1. When my father was in the Army (1950's) there was an encephalitis outbreak at Fort Dix, so the men were instructed to report any mosquito bites to the medical staff. Dad got bitten and duly checked in; after a cursory exam the doctor informed him that he couldn't really do much in the absence of symptoms, and in any case, only the females carried encephalitis. Dad--at the time--didn't know that only the females bite and was a bit confused as to how in hell he was to know male from female, and the doctor didn't know either! After he told me that story, I was less than surprised to read about many doctors not knowing what to do for snakebite, etc.

  2. Doctors have to know way more than a human being possibly can. The example I most I frequently hear about is spider-bite diagnoses that show the doctor really doesn't know spiders.

    It's interesting that this doc didn't know which mosquitoes bite. That's common knowledge now, but it must not have been back then.

  3. You're not alone- we're being "invaded" by hungry swarms of mosquitos too. I have become a very skilled mosquito hunter out of necessity. My window screens, insect repellants and "pet spiders" have been unable to control them.
    Speaking of Culex, I had to correct the local newspaper which had supossedly quoted a doctor as calling the problem mosquitos "Pulesck". The journalist had obviously not bothered to ask how the word was spelled and wrote what he thought he heard. Sometimes I just feel ashamed of working for that newspaper...

  4. "Pulesck" sounds like a good name for a mosquito. Or a James Bond villain.


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